Clinical UM Guideline

This document addresses automated insulin delivery systems for the management of diabetes mellitus. Automated insulin delivery systems combine insulin pumps and continuous interstitial glucose monitors (CGMs). These devices allow management of blood glucose with little to no input by the user. Such devices come in several configurations, including open-loop, hybrid closed-loop, and fully closed-loop systems.

Note: This document does not address supplies related to the use of automated insulin delivery devices.

Note: For additional information regarding diabetes care, please see:

• CG-DME-42 Continuous Glucose Monitoring Devices
• CG-DME-51 External Insulin Pumps
• CG-SURG-79 Implantable Infusion Pumps

Medically Necessary:

Use of an open-loop or hybrid closed-loop automated insulin delivery system is considered medically necessary for individuals who meet the following criteria:

1. Type 1 diabetes mellitus; and
2. Age used in accordance with FDA approval or authorization (for example, age 2 years or older); and
3. Meets the following criteria below for personal long-term use of continuous interstitial glucose monitoring devices:
   1. Insulin injections are required multiple times daily or an insulin pump is used for maintenance of blood sugar control; and
   2. Both of the following (a and b):
      1. The individual or caregiver(s) demonstrates the following:
         1. An understanding of the technology, including use of the device to recognize alerts and alarms; and
         2. Motivation to use the device correctly and consistently; and
         3. Continued participation in a comprehensive diabetes treatment plan;
            and
      2. Any of the following are present, despite ongoing management using self-monitoring and insulin administration regimens to optimize care:
         1. Inadequate glycemic control, demonstrated by HbA1c measurements above target; or
         2. Persistent fasting hyperglycemia; or
         3. Recurring episodes of hypoglycemia (blood glucose <54 mg/dL); or
         4. Hypoglycemia unawareness that puts the individual or others at risk; or
         5. In children and adolescents with type 1 diabetes who have achieved HbA1c levels below 7.0%, when treatment is intended to maintain target HbA1c levels and limit the risk of hypoglycemia.

Use of a fully closed-loop device automated insulin delivery system is considered medically necessary for individuals who meet the following criteria:

1. Type 1 diabetes mellitus; and
2. Age used in accordance with FDA approval or authorization (for example, age 6 years or older); and
3. Presence of diabetes for at least 12 months; and
4. Diabetes managed using the same regimen (either pump or multiple daily injections, with or without continuous glucose monitoring) for 3 months or longer; and
5. Meets the following criteria below for personal long-term use of continuous interstitial glucose monitoring devices:
   1. Insulin injections are required multiple times daily or an insulin pump is used for maintenance of blood sugar control; and
   2. Both of the following (a and b):
      1. The individual or caregiver(s) demonstrates the following:
         1. An understanding of the technology, including use of the device to recognize alerts and alarms; and
         2. Motivation to use the device correctly and consistently; and
         3. Continued participation in a comprehensive diabetes treatment plan;
            and
      2. Any of the following are present, despite ongoing management using self-monitoring and insulin administration regimens to optimize care:
         1. Inadequate glycemic control, demonstrated by HbA1c measurements above target; or
         2. Persistent fasting hyperglycemia; or
         3. Recurring episodes of hypoglycemia (blood glucose <54 mg/dL); or
         4. Hypoglycemia unawareness that puts the individual or others at risk; or
         5. In children and adolescents with type 1 diabetes who have achieved HbA1c levels below 7.0%, when treatment is intended to maintain target HbA1c levels and limit the risk of hypoglycemia.

Continued use of an open-loop, hybrid closed-loop, or fully closed-loop automated insulin delivery system is considered medically necessary when there is documentation that the device has resulted in clinical benefit (for example, improved or stabilized HbA1c control or fewer episodes of symptomatic hypoglycemia or hyperglycemia).

Replacement of a previously approved open-loop, hybrid closed-loop, or fully closed-loop automated insulin delivery system is considered medically necessary when the medically necessary criteria above have previously been met and all of the criteria below have been met:

1. The device is out of warranty; and
2. The device is malfunctioning; and
3. The device cannot be refurbished.

Not Medically Necessary:

Use of an open-loop, hybrid closed-loop, or fully closed-loop automated insulin delivery system is considered not medically necessary when the criteria above have not been met.

Continued use of an open-loop, hybrid closed-loop, or fully-closed loop automated insulin delivery system is considered not medically necessary when continued use criteria above have not been met.

Replacement of currently functional and warrantied open-loop, hybrid closed-loop, or fully closed-loop automated insulin delivery system is considered not medically necessary when the replacement criteria above have not been met.

Use of a non-FDA-approved open-loop, hybrid closed-loop, or fully closed-loop automated insulin delivery system is considered not medically necessary under all circumstances.

The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:
For the following codes, or when the code(s) describes an automated insulin delivery system:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for all other diagnoses not listed; or when the code describes a procedure, device or situation designated in the Clinical Indications section as not medically necessary.

Diabetes and Diabetes Management

Approximately 37 million Americans have been diagnosed with diabetes and another 8.5 million are believed to have undiagnosed disease. (American Diabetes Association (ADA, 2024). Diabetes mellitus, the fourth leading cause of death in the U.S., is a chronic condition, marked by impaired metabolism of carbohydrate, protein and fat from resistance to or absence of insulin. Management of diabetes mellitus involves normalization of blood sugar.

The most common forms of diabetes are referred to as Type 1 and Type 2. Type 1 can occur at any age, but is most commonly diagnosed from infancy to late 30s. In type 1 the pancreas produces little to no insulin, and the body’s immune system destroys the insulin-producing cells in the pancreas. Type 2 typically develops after age 40, but has recently begun to appear with more frequency in children. In type 2, the pancreas produces insulin, but the body does not produce enough or is not able to use it effectively.

Adequate glycemic control is critical for directing therapy in individuals with diabetes. Ideal blood sugar concentration range is between 70 mg/dL to 180 mg/dL. Hyperglycemia, defined as blood glucose concentrations above 200 mg/dL 1 to 2 hours following a meal is associated with headaches, thirst, fatigue, blurred vision, hunger, difficulty concentrating, and coma. Long-term exposure to hyperglycemia has been associated with organ damage (including loss of function of the kidney, liver, heart, and eyes), peripheral nerve damage, and high blood pressure. Hypoglycemia is defined as an episodes of an abnormally low plasma glucose concentration (with or without symptoms) that expose the individual to harm. A blood glucose concentration between 54 mg/dL and 69 mg/dL, considered mild hypoglycemia, may include hunger or nausea, elevated heart rate, fatigue, difficulty concentrating, and tingling of the oral area. Serious hypoglycemia, defined as a blood glucose concentration < 54 mg/dL, has been associated with confusion, loss of coordination, blurry vision, loss of consciousness and seizures. As noted by the Endocrine Society (2023), blood glucose concentrations < 54 mg/dL is associated with increased risk for cognitive dysfunction and mortality. Individuals with persistent fasting hyperglycemia, hypoglycemia unawareness that puts the individual or others at risk, or recurrent episodes of serious hypoglycemia (< 54 mg/dL) may benefit from use of continuous interstitial glucose monitoring devices and automated insulin delivery devices if ongoing management using self-monitoring and insulin administration regimens to optimize care has not resulted in adequate glycemic control.

A common clinical indicator of adequate blood sugar control is glycosylated hemoglobin, also known as hemoglobin A1c, or HbA1c. The ADA has stated that an appropriate target for HbA1c concentrations in most non-pregnant adults with diabetes is 7% or lower (though appropriate targets vary and are individualized).

When the use of multiple daily insulin injection therapy does not provide adequate control of blood sugar levels, an insulin pump may be recommended. These devices are worn externally with insulin infused subcutaneously through a catheter placed under the skin of the abdomen. The pumps can administer insulin at a set (basal) rate and provide injections (bolus) as needed. The pump typically has a syringe reservoir that has a 2- to 3-day insulin capacity. The purpose of the insulin pump is to provide an accurate, continuous, controlled delivery of insulin which can be regulated by the user to achieve intensive glucose control.

Whether an individual with diabetes uses injection therapy or an insulin pump, the individual needs to check blood glucose concentrations multiple times a day to make sure they are staying within normal blood glucose range. As with injection therapy, self-monitoring blood glucose management may be insufficient. In such circumstances, the use of a CGM may be warranted. These devices measure glucose concentrations in the fluid in between the body’s cells, also known as interstitial fluid. They are designed to provide real-time glucose measurements, which have been found to accurately reflect blood glucose levels.

Automated Insulin Delivery Devices

Automated insulin delivery systems combine an insulin pump and CGM, either as separate devices or as a device that incorporates both functions. These devices may be called “open-loop,” “hybrid closed-loop,” or “closed-loop.” These terms refer to how the devices interact with each other, as well as how the individual interacts with them.

Open-loop Devices

Open-loop devices require the intervention of the individual being treated to manage the insulin administration by setting a basal rate and initiating prandial bolus dosing. Most open-loop devices require self-monitoring of blood glucose concentrations as well. Open-loop devices may include a low glucose suspend feature that temporarily stops insulin delivery for a set period of time when the CGM device detects that glucose concentrations have reached a pre-set lower threshold. Some open-loop devices may go a step further and involve a “predictive” low glucose suspend feature, also known as a “threshold suspend” feature. This feature uses a predictive algorithm to determine when glucose concentrations are headed towards a pre-set lower threshold and then decreases or suspends insulin delivery before the threshold is reached.

Multiple well-designed and conducted studies addressing the use of open-loop threshold suspend-type devices have been published and demonstrated a significant benefit to individuals who utilized threshold suspend-type devices, with significant reduction in severe hypoglycemic events (Agrawal, 2015; Bergenstal, 2013; Forlenza, 2019; Gómez, 2017; Ly, 2013.

Hybrid Closed-Loop Devices

Hybrid closed-loop devices eliminate the requirement of routine manual adjustment of pump administration rates, with the insulin pump and CGM devices working together to predict and calculate insulin dose requirements. However, these types of devices still require manual calculation and administration of pre-meal insulin bolus doses, hence the “hybrid” moniker. Self-monitoring of blood glucose concentrations is not typically requires with these types of devices.

Hybrid closed-loop systems can increase, decrease, or stop insulin delivery automatically beyond pre-set infusion rates in response glucose concentration measurements from a paired CGM device. Most available devices have two modes, Manual and Automatic. In Manual mode, the device operates in a similar fashion to a low glucose suspend threshold device, stopping insulin delivery in response to low glucose measurements by the CGM. In Automatic mode, the device can automatically adjust basal insulin infusion rates to increase, decrease, or suspend delivery based on CGM data. In either mode, the user must manually deliver prandial insulin. The critical difference between threshold suspend-type devices and the hybrid closed-loop system is the ability to automatically vary basal insulin infusion rates based on CGM data.

Similar to open-loop devices, there have been multiple high quality studies demonstrating significant clinical outcomes benefit from the use of hybrid closed-loop devices (Bergenstal, 2016; Breton, 2020 and 2021; Brown, 2019 and 2021; Collyns, 2021 ; Ekhlaspour, 2019; Forlenza, 2018; Garg, 2017; Isganaitis, 2021; Kanapka, 2021; McAuley, 2020; Messer, 2018 and 2021; Nimri, 2017; Sherr, 2020; van Beers, 2017). These studies demonstrate a significant incremental benefit of automated hybrid closed-loop control of insulin administration compared to other treatment methods. Additionally, expert clinical opinion supports the use of these devices in light of the potential significant benefits available to the most at-risk individuals with type 1 diabetes.

Closed-Loop Devices

Finally, “closed-loop” systems are available that require no intervention by the treated individual when under normal operating conditions. On May 23, 2023, the FDA granted the first 510K clearance to a fully closed-loop device, the Beta Bionics iLet ACE Pump and Dosing Decision Software for people 6 years of age and older with type 1 diabetes. The Bionic Pancreas Research Group published a series of articles in 2022 from the Clinical Trial Registry NCT04200313 reporting on the clinical outcomes of the iLet system in both pediatric and adult populations with type 1 diabetes. The study populations reported in these publications may have overlap.

Their first publication (Russell, 2022) described the results of a randomized controlled trial (RCT) enrolling subjects with type 1 diabetes aged 6 to 79 years and using insulin for at least 1 year. Subjects who were 18 years of age or older were randomly assigned in a 2:2:1 fashion to use the iLet system with insulin aspart or insulin lispro (bionic-pancreas group), the iLet system with fast-acting insulin aspart, or standard-care insulin delivery plus use of the unblinded Dexcom G6 CGM (standard care group). Subjects 6 to 17 years of age were randomly assigned in a 2:1 fashion to the bionic-pancreas group or the standard-care group. Overall, 219 subjects were included in the bionic-pancreas group and 107 in the standard care group. Baseline HbA1c levels ranged from 5.5 to 13.1%. The trial period was 13 weeks. The primary outcome measure, mean HbA1c at 13 weeks, was reported to have decreased from 7.9% at baseline to 7.3% in the bionic-pancreas group at 13 weeks. No change was reported in the standard-care group (7.7% at both time points, p<0.001 between groups). The percentage of time glucose levels were below 54 mg/dL was found to be noninferior in the bionic-pancreas group vs. the standard-care group. The between-group difference in the percentage of time spent in target range  was 11 percentage points better in the bionic-pancreas group (p<0.001). Percentage of time spent below 70 mg/dL did not differ significantly between the two groups (p=0.51). Mean adjusted difference in HbA1c levels at 13 weeks was similar in the adult and pediatric cohorts. A total of 244 adverse events were reported in 126 subjects in the bionic-pancreas group and 10 in 8 subjects in the standard-care group. These included 214 episodes of hyperglycemia with or without ketosis in the bionic-pancreas group and 2 episodes in the standard-care group. Nearly all the events in the bionic-pancreas group were attributed to infusion-set failure. Two children in the bionic-pancreas group received insulin glargine due to prolonged periods of hyperglycemia despite the bionic pancreas administering the maximum amount of insulin allowed by its algorithms. The authors reported that the use of the bionic pancreas was associated with a greater reduction in HbA1c vs. standard care in this study cohort.

Lynch (2022) reported the results of an extension study involving 90 of the 107 standard care group subjects from the Russell study who used the iLet system for 13 weeks following the end of the previous trial. There were 42 subjects in the adult cohort and 48 in the pediatric cohort. Ninety-three percent of subjects completed the study. HbA1c was reported to have decreased from 7.7% to 7.1% (p<0.001) and similar in the adult and pediatric cohorts. Improvement in HbA1c of > 0.5% was achieved by 46% of participants. The percentage achieving an HbA1c level < 7.0% increased from 26% to 39% (p=0.02) and < 7.5 from 38% to 72% (p<0.001). Mean time in range increased from 53% to 65% (p<0.001). Two severe hypoglycemia events were reported in 1 adult subject who also experienced two such events during the RCT while using multiple daily injection therapy. Neither event was related to a device malfunction. A single pediatric participant developed diabetic ketoacidosis associated with infusion set failure. This study demonstrated significant improvement in diabetes-related outcomes in this cohort with the use of the iLet system.

Messer (2022) reported the results of an RCT involving 165 subjects with type 1 diabetes aged 6-17 years and using insulin for at least 1 year who were randomly assigned in a 2:1 fashion to using the iLet system  (n=112) or their standard treatment regimen plus a CGM device, if not already used (n=53). Mean HbA1c decreased from 8.1 to 7.5% at 13 weeks in the iLet group and was unchanged at 7.8% in the standard care group (p<0.001). Fifty-one percent of the iLet group vs. 8% of the standard care group had improved HbA1c by > 0.5% (p<0.001). In the subgroup of subjects with baseline HbA1c > 9%, the treatment effect more significant, with mean measures in the iLet group decreasing from 9.7% at baseline to 7.9% at 13 weeks vs. 9.7% to 9.8% in the standard care group. Over 13 weeks, mean time in range was increased by 10% and mean CGM-measured glucose concentrations were reduced by 15 mg/dL on average in the iLet group vs. the standard care group (p<0.001). Statistically significant differences favoring the iLet group also were reported with regard to time > 180 mg/dL, time > 250 mg/dL, and mean glucose SD (p<0.001 for all). No between-group differences were reported with regard to the incidence of hypoglycemia (p=0.24). However, baseline rates of hypoglycemia were low (0.2% in the iLet group and 0.22% in the standard group). Mean total daily insulin dose was not significantly different between groups. Three severe hypoglycemia events were reported in the iLet group (2.7% of 112 participants) and one in the standard care group (1.9% of 53 participants). No cases of diabetic ketoacidosis were reported. Most adverse events were related to hyperglycemia with or without ketosis and were attributable to infusion set failure.

Kruger (2022) reported the results of an RCT involving 161 adult subjects with type 1 diabetes and using insulin for at least 1 year randomized in a 2:1 fashion to use the iLet system with insulin aspart or insulin lispro (n=107) or their standard care (n=54) and followed for 13 weeks. The study was completed by 104 (97%) iLet-group subjects and all of the standard-care group subjects. Mean HbA1c decreased from 7.6% to 7.1% in the iLet group and from 7.6% to 7.5% in the standard care group (p<0.001 between groups). HbA1c improved by > 0.5% in 43% of the iLet-group subjects vs. 17% of the standard-care group subjects (p<0.001) and by > 1.0% in 23% vs. 4% of subjects, respectively (p=0.009). For subjects with baseline HbA1c > 8.0% (n=55), mean HbA1c decreased from 8.9% to 7.4% at 13 weeks in the iLet group vs. from 8.8% to 8.3% in the standard-care group (p<0.001). Mean time in range was increased by 11% and mean CGM-assessed glucose was reduced by 16 mg/dL in the iLet group vs. the standard-care group (p<0.001). Mean time > 180 mg/dL and > 250 ng/dL were all significantly better in the iLet group vs. standard-care group (p<0.001 for both). No significant differences between groups were reported for time < 70 mg/dL or < 54 Mg/dL (p=0.51 and p=0.33, respectively). A total of 7 severe hypoglycemia events occurred in 7 iLet group subjects (6.5%) and 2 events in 1 subject in the standard-care group (1.9%). The rates of severe hypoglycemia were 25.5 and 14.2 per 100 person-years, respectively (p=0.40).

Beck (2022) reported on an RCT involving 275 adults with type 1 diabetes and using insulin for at least 1 year who were randomized on a 2:2:1 basis to treatment with the iLet system with fast acting insulin aspart (n=114), the iLet system with standard insulin (n=107), or standard care (n=54). Mean HbA1c decreased from 7.8% to 7.1% at 13 weeks in the fast-insulin group vs. 7.6% to 7.5% in the standard-care group (p<0.001). Mean time in range, time > 180 mg/dL, and time > 250 mg/dL were significantly in favor of the fast-insulin group (p<0.001 for all). No difference was noted with regard to time < 70 mg/dL. No significant differences were noted between the fast and standard glucose groups with regard to mean glucose concentration or time < 70 mg/dL. However, time in range was significantly better in the fast-insulin group (p=0.0005). There were three severe hypoglycemia events in 3 fast-insulin group subjects (2.6%), two events in 1 participant in the standard-care group (1.9%), and seven events in 7 standard-insulin group subjects (6.5%), with no significant differences noted between groups (p=0.83 fast insulin vs. standard of care and fast insulin vs. standard insulin p=0.20). Two fast-insulin subjects experienced one diabetic ketoacidosis event caused by an infusion set failure. There were no such events in the standard insulin or standard care groups.

The body of evidence to-date for the iLet closed-loop automated insulin dosing system demonstrates significant improvements in HbA1c measures, as well as time in range and time below < 180 mg/dL when compared to other methods of glucose control, including multiple daily injections, sensor-augmented pump therapy and use of hybrid closed-loop devices.

Other closed-loop systems are under investigation, but have not yet received FDA approval or clearance.

Forlenza (2016) published the results of a small RCT involving 14 subjects randomized to treatment with either closed-loop treatment with the Medtronic ePID (external physiological insulin delivery) 2.0 controller vs. MDI therapy with blinded CGM (n=7 in each group) for a 72-hour period. The results indicated that mean serum glucose values were significantly lower in the closed-loop group vs. the controls (111 mg/dL vs. 130 mg/dL, p=0.003). This was achieved without increased risk of hypoglycemia, as demonstrated by the percentage of time < 70 mg/dL being lower in the closed-loop group vs. controls (1.9% vs. 4.8%, p=0.46). While the authors concluded that their results suggest that closed-loop therapy is superior to conventional therapy in maintaining euglycemia without increased hypoglycemia, additional investigation is warranted in larger studies.

Thabit (2017) reported on an RCT involving 40 adult subjects with type 2 diabetes assigned to a 72-hour treatment period with the closed-loop Florence D2W-T2 automated system or standard of care with subcutaneous insulin therapy. The Florence D2W-T2 is composed of a tablet computer-based control algorithm linked to an Abbott Freestyle Navigator II CGM and a Sooil DANA R Diabecare insulin pump. In this study, the proportion of time spent in target range was significantly higher in the closed-loop group vs. the control group (59.8% vs. 38.1%, p=0.004). The proportion of time spent with glucose concentrations > 10.0 mmol/L was significantly lower in the closed-loop group vs. controls (30.1 vs. 49.1, p=0.011). No significant differences between groups were reported for mean glucose concentrations or time spent with glucose concentrations below target range. Glucose variability was significantly reduced in the Florence group vs. controls (coefficient of variation [CV], 27.9 vs. 33.4, p=0.042), and nocturnal time spent within range was significantly greater in the Florence group as well (68.9% vs. 48.8%, p=0.007). No episodes of severe hypo- or hyperglycemia with ketonemia occurred in either group. As with the previously described study, these results are promising, but additional investigation involving larger studies is needed.

Brown (2017) reported on the results of a randomized crossover study involving 40 subjects with type 1 diabetes comparing the use of a hybrid closed-loop device (Roche Accu-Chek Spirit Combo connected to either a DexCom G4 Platinum or AP Share CGM) vs. a closed-loop system (Diabetes Assistant [DiAs] portable artificial pancreas platform, which connected the pumps and CGM devices wirelessly to a smartphone running the DiAs algorithm) to evaluate performance in controlling overnight glycemic control. Subjects were evaluated in 5 consecutive day periods wearing either device. The closed-loop evaluations were conducted at either a hotel or study center and the control trials were done at the subjects’ usual environment. The primary endpoint of time in the target range improved in closed-loop trials vs. the pump trials (mean=78.3% vs. 71.4%; p=0.003) when measured for 24 hours during the study period. The time in the target range was also improved in the overnight hours (23:00 to 07:00) in closed-loop trials vs. the pump trials (85.7% vs. 67.6%; p<0.001). Mean overnight glucose concentrations were significantly lower during the closed-loop trials vs. the pump trials (137.2 vs 154.9 mg/dL; p<0.001). Mean glucose concentrations upon awakening were closer to the algorithm target of 120 mg/dL in the closed-loop trials vs. pump trials (123.7 vs. 145.3 mg/dL; p<0.001). The time spent in range during both overnight and during the 24-hour observation periods was significantly better in the closed-loop trials vs. the pump trials (p=0.002 and p<0.001, respectively), likewise, the time spent in the hyperglycemic range (< 180 mg/dL) was significantly less in the closed-loop trials (p<0.001). No instances of ketoacidosis or hypoglycemia requiring outside intervention were reported. The DiAs system is not currently approved or cleared by the FDA and not commercially available in the U.S., and No rigorously designed and conducted studies of the DiAs system outside the investigational setting have been published.

An RCT involving 136 hospitalized subjects with type 2 diabetes aged 18 years and older in noncritical care was described by Bally in 2018. Subjects were assigned to either standard care with manual blood glucose monitoring and conventional subcutaneous insulin therapy (n=66) or treatment with an experimental closed-loop system (n=70). The system used a Dana Diabecare insulin pump, Abbott Freestyle Navigator II CGM, and a proprietary control algorithm run on a tablet computer. The mean percentage of time that the sensor glucose measurement was in the target range of 100-180 mg/dL was reported to be 65.8% in the closed-loop group vs. 41.5% in the control group (p<0.001). Values above the target range were reported in 23.6% and 49.5% of subjects, respectively (p<0.001). The mean glucose level was 154 mg/dL in the closed-loop group vs. 188 mg/dL (p<0.001). No significant between-group differences were reported with regard to the duration of hypoglycemia or daily insulin usage. Finally, no episode of severe hypoglycemia or clinically significant hyperglycemia with ketonemia occurred in either group. As with the DiAs system, this system is not currently approved or cleared by the FDA and not commercially available in the U.S. and no rigorously designed and conducted studies outside the investigational setting have been published.

The results of the studies addressing the non-iLet devices demonstrate significant benefits. However, the utility of other closed-loop devices remain unclear. Until these devices have received FDA approval or clearance and are available on the market in the U.S. their use is limited to the research setting.

FDA Authorized/Approved Devices*

* This may not be an all-inclusive list. Additional CGM devices may be FDA approved and available in the US.

Other Information

There are other automated insulin delivery devices under development which attempt to more fully mimic the action of the pancreas through the administration of both insulin and glucagon. Such devices have been be referred to as a bionic pancreases or dual-hormone artificial pancreases. To date, no devices of this type have received FDA approval or clearance, and they are not addressed in this document.

Specialty Medical Society Recommendations

The ADA Standards of Medical Care in Diabetes-2024 has recommendations regarding the use of continuous glucose monitoring. These recommendations state:

6.5a An A1C goal for many nonpregnant adults of <7% (<53 mmol/mol) without significant hypoglycemia is appropriate. A
6.6 On the basis of health care professional judgment and the preference of the person with diabetes, achievement of lower A1C levels than the goal of 7% (53 mmol/mol) may be acceptable and even beneficial if it can be achieved safely without significant hypoglycemia or other adverse effects of treatment. B
7.4 The type(s) and selection of devices should be individualized based on a person’s specific needs, preferences, and skill level. In the setting of an individual whose diabetes is partially or wholly managed by someone else (e.g., a young child or a person with cognitive impairment or dexterity, psychosocial, and/or physical limitations), the caregiver’s skills and preferences are integral to the decision-making process. E
7.5 When prescribing a device, ensure that people with diabetes and caregivers receive initial and ongoing education and training, either in person or remotely, and ongoing evaluation of technique, results, and the ability to utilize data, including uploading/sharing data (if applicable), to monitor and adjust therapy. C
7.6 People with diabetes who have been using CGM, continuous subcutaneous insulin infusion (CSII), and/or automated insulin delivery (AID) for diabetes management should have continued access across third-party payers, regardless of age or A1C levels. E
7.8 Initiation of CSII and/or AID early, even at diagnosis, in the treatment of diabetes can be beneficial depending on a person’s or caregiver’s needs and preferences. C
7.27 AID systems should be offered for diabetes management to youth and adults with type 1 diabetes A and other types of insulin-deficient diabetes E who are capable of using the device safely (either by themselves or with a caregiver). The choice of device should be made based on the individual’s circumstances, preferences, and needs. A
14.7 Frequent glucose monitoring before, during, and after exercise, via blood glucose meter or continuous glucose monitoring (CGM), is important to prevent, detect, and treat hypoglycemia and hyperglycemia associated with exercise. C
14.19 Automated insulin delivery (AID) systems should be offered for diabetes management to youth with type 1 diabetes who are capable of using the device safely (either by themselves or with caregivers). The choice of device should be made based on the individual’s and family’s circumstances, desires, and needs. A
14.22 A1C goals must be individualized and reassessed over time. An A1C of <7% (<53 mmol/mol) is appropriate for many children and adolescents. B
14.23 Less stringent A1C goals (such as <7.5% [<58 mmol/mol]) may be appropriate for youth who cannot articulate symptoms of hypoglycemia; have hypoglycemia unawareness; lack access to analog insulins, advanced insulin delivery technology, and/or CGM; cannot check blood glucose regularly; or have nonglycemic factors that increase A1C (e.g., high glycators). B
14.24 Even less stringent A1C goals (such as <8% [<64 mmol/mol]) may be appropriate for individuals with a history of severe hypoglycemia, limited life expectancy, or where the harms of treatment are greater than the benefits. B
14.25 Health care professionals may reasonably suggest more stringent A1C goals (such as <6.5% [<48 mmol/mol]) for selected individuals if they can be achieved without significant hypoglycemia, negative impacts on well-being, or undue burden of care or in those who have nonglycemic factors that decrease A1C (e.g., lower erythrocyte life span). Lower goals may also be appropriate during the honeymoon phase. B

In 2022 the American Association of Clinical Endocrinology (AACE) published clinical practice guidelines addressing the use of advanced technology in the management of persons with diabetes mellitus (Grunberger, 2021). Their recommendations in that document include the following:

R2.2.1 The AGP may be utilized to assess glycemic status in persons with diabetes. Grade B; Low Strength of Evidence; BEL 1
R2.2.2 When using the AGP, a systematic approach to interpret CGM data is recommended:

1. Review overall glycemic status (eg, GMI, average glucose)
2. Check TBR, TIR, and TAR statistics, focusing on hypoglycemia (TBR) first. If the TBR statistics are above the cut-point for the clinical scenario (ie, for most with
3. T1D >4% <70 mg/dL; >1% <54 mg/dL), the visit should focus on this issue. Otherwise, move on to the TIR and TAR statistics.
4. Review the 24-hour glucose profile to identify the time(s) and magnitude(s) of the problem identified.
5. Review treatment regimen and adjust as needed.
   Grade B; Low Strength of Evidence; BEL 1

R2.9.2 AID systems are strongly recommended for all persons with T1D, since their use has been shown to increase TIR, especially in the overnight period, without causing an increased risk of hypoglycemia. Given the improvement in TIR and the reduction in hyperglycemia with AID, this method of insulin delivery is preferred above other modalities. For persons with diabetes with suboptimal glycemia, significant glycemic variability, impaired hypoglycemia awareness, or who allow for permissive hyperglycemia due to the fear of hypoglycemia, such AID systems should be considered. Grade A; High Strength of Evidence; BEL 1

Automated insulin delivery systems: A device that combines the functions of an external insulin pump and a CGM device to create a device that attempts to mimic normal physiological functioning, but requires some intervention by the user. Such devices control the majority of insulin administration tasks, such as measuring blood glucose concentrations and calculation and management of insulin administration. As noted above, there are several categories of this type of device: open-loop systems and hybrid closed-loop systems.

Automated insulin dosing system: Devices similar to automated insulin delivery systems, but do not require daily intervention by the user. See closed-loop systems below.

Closed-loop systems: A type of automated insulin delivery device consisting of an external insulin infusion pump device, a CGM device, and possibly a third device that acts as a controller for the system. This type of system is able to increase, decrease or stop insulin delivery automatically beyond pre-set infusion rates in response to glucose concentration measurements taken by the CGM. Individuals using this type of device do not need to calculate and adjust infusion rates to compensate for prandial boluses, and little to no input is needed by the individual during normal functioning.

Continuous interstitial glucose monitoring (CGM) device: A device applied to the skin that contains a sensor implanted into the skin to measure glucose concentrations in the interstitial fluid. Such devices may be used to create a record of glucose concentrations over time to allow analysis by a medical professional. They may also measure and provide real-time glucose concentration data to allow an individual or automated insulin delivery system to adjust insulin delivery rates to provide better control of blood glucose concentrations.

External insulin infusion pumps: A device that is worn externally and attached to a temporary subcutaneous insulin catheter. An integrated computer controls a pump mechanism that administers insulin at a set rate or provide bolus injections as needed.

Flash CGM: A type of CGM device that requires the use of a device access glucose data from a sensor on a per-need basis. Glucose concentration data is not continuously visible with this type of device.

Glycemic: Having to do with blood sugar (glucose) levels.

Glycemic control: The ability of an individual’s body to control blood glucose concentrations within a specific physiologic range, either on its own or with the assistance of medical therapy.

Glycosylated hemoglobin (HbA1c) test: A laboratory test that provides the percentage of a specific type of modified hemoglobin in the blood. This test ascertains the level of diabetic blood glucose control over the past three to four months.

Hybrid closed-loop systems: A type of automated insulin delivery device consisting of an external insulin infusion pump device and a CGM device. This type of system is able to increase, decrease or stop insulin delivery automatically beyond pre-set infusion rates in response glucose concentration measurements taken by the CGM. Individuals using this type of device need to calculate and adjust infusion rates for prandial boluses.

Hyperglycemia: A condition characterized by excessively high blood glucose concentrations, generally considered greater than 200 mg/dL one to two hours following a meal in individuals with diabetes.

Hypoglycemia: In patients with diabetes, defined as an episode of an abnormally low plasma glucose concentration (with or without symptoms) that expose the individual to harm. Serious hypoglycemia is generally considered a blood glucose level less than 54 mg/dL.

Interstitial glucose: Glucose present in the fluid present in spaces between the tissue cells of the body.

Low glucose suspend feature: A function of an automated insulin delivery system that uses the data from a CGM to detect when blood glucose concentrations pass below a pre-set threshold. When that occurs, the pump function temporarily stops insulin delivery with the goal of avoiding or shortening hypoglycemic events.

Open-loop system: A type of automated insulin delivery system that integrates an external insulin pump and CGM device. This type of device requires manual adjustment of insulin administration rates based on CGM data, as well as manual calculation and administration of pre-meal insulin bolus doses. These types of devices require self-adjustment of the basal insulin infusion rate and most require a blood glucose measurement to confirm CGM data.

Predictive low glucose management (PLGM): A feature of some CGM systems that uses a computer algorithm to monitor blood glucose concentration trend data to predict when concentrations will be approaching the preset low threshold and decrease or stop insulin administration to avoid hypoglycemic events.

Real time CGM: A type of CGM device that provides real-time, continuously visible glucose concentration data to the user.

Type 1 diabetes: A condition characterized by the impaired or inability of the pancreas to produce insulin. Sometimes known as ‘juvenile diabetes.’

Type 2 diabetes: A condition characterized by a person’s body losing the ability to use insulin properly, a problem referred to as insulin resistance.

Peer Reviewed Publications:

1. Agrawal P, Zhong A, Welsh JB, et al. Retrospective analysis of the real-world use of the threshold suspend feature of sensor-augmented insulin pumps. Diabetes Technol Ther. 2015; 17(5):316-319.
2. Bally L, Thabit H, Hartnell S, et al. Closed-loop insulin delivery for glycemic control in noncritical care. N Engl J Med. 2018; 379(6):547-556
3. Beck RW, Russell SJ, Damiano ER, et al. A multicenter randomized trial evaluating fast-acting insulin aspart in the bionic pancreas in adults with Type 1 diabetes. Diabetes Technol Ther. 2022; 24(10):681-696.
4. Bergenstal RM, Garg S, Weinzimer SA, et al. Safety of a hybrid closed-loop insulin delivery system in patients with Type 1 diabetes. JAMA. 2016; 316(13):1407-1408.
5. Bergenstal RM, Klonoff DC, Garg SK, et al.; ASPIRE In-Home Study Group. Threshold-based insulin-pump interruption for reduction of hypoglycemia. N Engl J Med. 2013; 369(3):224-232.
6. Bionic Pancreas Research Group; Russell SJ, Beck RW, Damiano ER, et al. Multicenter, randomized trial of a bionic pancreas in Type 1 diabetes. N Engl J Med. 2022; 387(13):1161-1172.
7. Breton MD, Kanapka LG, Beck RW, et al. A randomized trial of closed-loop control in children with type 1 diabetes. N Engl J Med. 2020; 383(9):836-845.
8. Breton MD, Kovatchev BP. One year real-world use of the Control-IQ advanced hybrid closed-loop technology. Diabetes Technol Ther. 2021; 23(9):601-608.
9. Brown SA, Beck RW, Raghinaru D, et al.; iDCL Trial Research Group. Glycemic outcomes of use of CLC versus PLGS in type 1 diabetes: a randomized controlled trial. Diabetes Care. 2020; 43(8):1822-1828.
10. Brown SA, Breton MD, Anderson SM, et al. Overnight closed-loop control improves glycemic control in a multicenter study of adults with type 1 diabetes. J Clin Endocrinol Metab. 2017; 102(10):3674-3682.
11. Brown SA, Kovatchev BP, Raghinaru D, et al.; iDCL Trial Research Group. Six-month randomized, multicenter trial of closed-loop control in type 1 diabetes. N Engl J Med. 2019; 381(18):1707-1717.
12. Buckingham BA, Bailey TS, Christiansen M, et al. Evaluation of a predictive low-glucose management system in-clinic. Diabetes Technol Ther. 2017; 19(5):288-292.
13. Collyns OJ, Meier RA, Betts ZL, et al. Improved glycemic outcomes with Medtronic MiniMed Advanced hybrid closed-loop delivery: results from a randomized crossover trial comparing automated insulin delivery with predictive low glucose suspend in people with type 1 diabetes. Diabetes Care. 2021; 44(4):969-975.
14. Ekhlaspour L, Forlenza GP, Chernavvsky D, et al. Closed loop control in adolescents and children during winter sports: use of the Tandem Control-IQ AP system. Pediatr Diabetes. 2019; 20(6):759-768.
15. Forlenza GP, Li Z, Buckingham BA, et al. Predictive low-glucose suspend reduces hypoglycemia in adults, adolescents, and children with type 1 diabetes in an at-home randomized crossover study: results of the PROLOG trial. Diabetes Care. 2018; 41(10):2155-2161.
16. Forlenza GP, Nathan BM, Moran AM, et al. Successful application of closed-loop artificial pancreas therapy after islet autotransplantation. Am J Transplant. 2016; 16(2):527-534.
17. Forlenza GP, Pinhas-Hamiel O, Liljenquist DR, et al. Safety evaluation of the MiniMed 670G System in children 7-13 years of age with type 1 diabetes. Diabetes Technol Ther. 2019; 21(1):11-19.
18. Garg SK, Weinzimer SA, Tamborlane WV, et al. Glucose outcomes with the in-home use of a hybrid closed-loop insulin delivery system in adolescents and adults with type 1 diabetes. Diabetes Technol Ther. 2017; 19(3):155-163.
19. Gill M, Chhabra H, Shah M, et al. C-peptide and beta-cell autoantibody testing prior to initiating continuous subcutaneous insulin infusion pump therapy did not improve utilization or medical costs among older adults with diabetes mellitus. Endocr Pract. 2018; 24(7):634-645.
20. Gómez AM, Marín Carrillo LF, Muñoz Velandia OM, et al. Long-term efficacy and safety of sensor augmented insulin pump therapy with low-glucose suspend feature in patients with Type 1 diabetes. Diabetes Technol Ther. 2017; 19(2):109-114.
21. Isganaitis E, Raghinaru D, Ambler-Osborn L, et al.; iDCL Trial Research Group. Closed-loop insulin therapy improves glycemic control in adolescents and young adults: outcomes from the international diabetes closed-loop trial. Diabetes Technol Ther. 2021; 23(5):342-349.
22. Kanapka LG, Wadwa RP, Breton MD, et al.; iDCL Trial Research Group. Extended use of the Control-IQ closed-loop control system in children with type 1 diabetes. Diabetes Care. 2021; 44(2):473-478.
23. Kropff J, Del Favero S, Place J, et al.; AP@home Consortium. 2 month evening and night closed-loop glucose control in patients with type 1 diabetes under free-living conditions: a randomised crossover trial. Lancet Diabetes Endocrinol. 2015; 3(12):939-947.
24. Kruger D, Kass A, Lonier J, et al. A multicenter randomized trial evaluating the insulin-only configuration of the bionic pancreas in adults with Type 1 diabetes. Diabetes Technol Ther. 2022; 24(10):697-711.
25. Leelarathna L, Dellweg S, Mader JK, et al.; AP@home Consortium. Day and night home closed-loop insulin delivery in adults with type 1 diabetes: three-center randomized crossover study. Diabetes Care. 2014; 37(7):1931-1937.
26. Ly TT, Nicholas JA, Retterath A, et al. Effect of sensor-augmented insulin pump therapy and automated insulin suspension vs standard insulin pump therapy on hypoglycemia in patients with type 1 diabetes: a randomized clinical trial. JAMA. 2013; 310(12):1240-1247.
27. Lynch J, Kanapka LG, Russell SJ, et al. The insulin-only bionic pancreas pivotal trial extension study: a multi-center single-arm evaluation of the insulin-only configuration of the bionic pancreas in adults and youth with Type 1 diabetes. Diabetes Technol Ther. 2022; 24(10):726-736.
28. McAuley SA, Lee MH, Paldus B, et al.; Australian JDRF Closed-Loop Research Group. Six months of hybrid closed-loop versus manual insulin delivery with fingerprick blood glucose monitoring in adults with type 1 diabetes: a randomized, controlled trial. Diabetes Care. 2020; 43(12):3024-3033.
29. Messer LH, Berget C, Pyle L, et al. Real-world use of a new hybrid closed loop improves glycemic control in youth with type 1 diabetes. Diabetes Technol Ther. 2021; 23(12):837-843.
30. Messer LH, Buckingham BA, Cogen F, et al. Positive impact of the bionic pancreas on diabetes control in youth 6-17 years old with Type 1 diabetes: a multicenter randomized trial. Diabetes Technol Ther. 2022; 24(10):712-725.
31. Messer LH, Forlenza GP, Sherr JL, et al. optimizing hybrid closed-loop therapy in adolescents and emerging adults using the MiniMed 670G system. Diabetes Care. 2018; 41(4):789-796.
32. Nimri R, Bratina N, Kordonouri O, et al. MD-Logic overnight type 1 diabetes control in home settings: a multicentre, multinational, single blind randomized trial. Diabetes Obes Metab. 2017; 19(4):553-561.
33. Pulkkinen MA, Varimo TJ, Hakonen ET, et al. 780G™ in 2- to 6-year-old children: safety and clinical outcomes after the first 12 weeks. Diabetes Technol Ther. 2023; 25(2):100-107.
34. Renard E, Farret A, Kropff J, et al.; AP@home Consortium. Day-and-night closed-loop glucose control in patients with type 1 diabetes under free-living conditions: results of a single-arm 1-month experience compared with a previously reported feasibility study of evening and night at home. Diabetes Care. 2016; 39(7):1151-1160.
35. Sherr JL, Buckingham BA, Forlenza GP, et al. Safety and performance of the Omnipod hybrid closed-loop system in adults, adolescents, and children with type 1 diabetes over 5 days under free-living conditions. Diabetes Technol Ther. 2020; 22(3):174-184.
36. Tauschmann M, Allen JM, Wilinska ME, et al. Sensor life and overnight closed-loop: a randomized clinical trial. J Diabetes Sci Technol. 2017; 11(3):513-521.
37. Thabit H, Hartnell S, Allen JM, et al. Closed-loop insulin delivery in inpatients with type 2 diabetes: a randomised, parallel-group trial. Lancet Diabetes Endocrinol. 2017; 5(2):117-124.
38. van Beers CA, DeVries JH, Kleijer SJ, et al. Continuous glucose monitoring for patients with type 1 diabetes and impaired awareness of hypoglycaemia (IN CONTROL): a randomised, open-label, crossover trial. Lancet Diabetes Endocrinol. 2016; 4(11):893-902.
39. Vigersky RA, Huang S, Cordero TL, et al. OpT2mise Study Group. Improved HbA1c, total daily insulin dose, and treatment satisfaction with insulin pump therapy compared to multiple daily insulin injections in patients with type 2 diabetes irrespective of baseline c-peptide levels. Endocr Pract. 2018; 24(5):446-452.
40. Weisman A, Bai JW, Cardinez M, et al. Effect of artificial pancreas systems on glycaemic control in patients with type 1 diabetes: a systematic review and meta-analysis of outpatient randomised controlled trials. Lancet Diabetes Endocrinol. 2017; 5(7):501-512.
41. Zisser H, Renard E, Kovatchev B, et al.; Control to Range Study Group. Multicenter closed-loop insulin delivery study points to challenges for keeping blood glucose in a safe range by a control algorithm in adults and adolescents with type 1 diabetes from various sites. Diabetes Technol Ther. 2014; 16(10):613-622.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American Diabetes Association. Common Terms. Available at: https://diabetes.org/about-diabetes/common-terms?gclid=EAIaIQobChMIs8K9r4HYgwMVHFhHAR3g9Q5zEAAYASAAEgL61PD_BwE. Accessed on January 12, 2024.
2. American Diabetes Association. Standards of Care in Diabetes-2024. Diabetes Care. 2024; 47(Suppl 1):S1-S321.
3. Grunberger G, Handelsman Y, Bloomgarden ZT, Fonseca VA, Garber AJ, Haas RA, Roberts VL, Umpierrez GE. American Association of Clinical Endocrinologists and American College of Endocrinology 2018 position statement on integration of insulin pumps and continuous glucose monitoring in patients with diabetes mellitus. Endocr Pract. 2018; 24(3):302-308.
4. Grunberger G, Sherr J, Allende M, et al. American Association of Clinical Endocrinology clinical practice guideline: the use of advanced technology in the management of persons with diabetes mellitus. Endocr Pract. 2021; 27(6):505-537.
5. McCall AL, Lieb DC, Gianchandani R, et al. Management of individuals with diabetes at high risk for hypoglycemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2023; 108(3):529-562.
6. U.S Food and Drug Administration. Summary of safety and effectiveness data for the MiniMed 670G system. September 28, 2016. Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf16/P160017b.pdf. Accessed on January 4, 2024.
7. U.S Food and Drug Administration. Summary of safety and effectiveness data for the MiniMed 780G system. April 21, 2023. Available at: https://www.accessdata.fda.gov/cdrh_docs/pdf16/P160017S091B.pdf . Accessed on January 4, 2024.
8. U.S Food and Drug Administration. Types of Artificial Pancreas Device Systems. Updated December 17, 2017. Available at: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/HomeHealthandConsumer/ConsumerProducts/ArtificialPancreas/ucm259555.htm. Accessed on January 4, 2024.

1. American Diabetes Association. 2020 Consumer guides. Available at: https://consumerguide.diabetes.org/. Accessed on January 4, 2024.
2. American Diabetes Association. Type 1 diabetes. Available at: http://www.diabetes.org/diabetes-basics/type-1/. Accessed on January 4, 2024.
3. American Diabetes Association. Type 2 diabetes. Available at: http://www.diabetes.org/diabetes-basics/type-2/?loc=db-slabnav/. Accessed on January 4, 2024.

Dexcom G7
FreeStyle Insulin Infusion Systems
iLet ACE Pump
iLet Dosing Decision Software
MiniMed 670G
MiniMed 770G
MiniMed 780G
Tandem t:slim X2 with Basal-IQ
Tandem t:slim X2 with Control-IQ

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.