Long-Term Accuracy and Safety of Next-Generation Implantable Continuous Glucose Monitoring System

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Investigators report the results of the PROMISE study, which evaluated the accuracy and safety of the next-generation Eversense continuous glucose monitoring system for patients with diabetes requiring insulin.

The next-generation Eversense continuous glucose monitoring (CGM) system was found to have sustained accuracy and safety up to 180 days, according to the results of a study published in Diabetes Technology & Therapeutics.

The PROMISE study (ClinicalTrials.gov Identifier: NCT03808376) was a prospective, multicenter study conducted at 8 centers in the United States between 2018 and 2020. Patients with type 1 (n=126) and type 2 (n=55) diabetes requiring insulin received the next-generation implantable Eversense CGM system. A subset of patients (n=96) received a second sensor in their other arm, and the secondary device was either identical (n=53) or a modified sacrificial boronic acid (SBA) sensor (n=43). Device detection rates, stability, survival, and safety were evaluated through 180 days.

The study cohort consisted of 53.0% women. Study participants had a mean age of 48.6 (standard deviation [SD], 14.9) years, 90.1% were White, mean glycated hemoglobin (HbA1c) was 7.6% (SD, 1.3%), mean body mass index (BMI) was 31.4 (SD, 7.2) kg/m2, the mean duration since a diagnosis of diabetes was 22.0 (SD, 13.3) years, and 50.8% used a continuous insulin infusion pump at baseline.

Compared with readings from the Yellow Springs Instrument (YSI) bedside glucose analyzer, accuracy of the Eversense CGM (mean percent 15%/15% of reference) on the basis of glucose ranges was 85.6% overall. Stratified by YSI glucose ranges, accuracy was lowest (82.7%) in the 81 to 180 mg/dL range and highest (90.6%) in the 301 to 350 mg/dL range. Accuracy between paired readings on the basis of time ranged from 80.0% on day 1 to 90.5% on day 60.

The confirmed detection rate for a hypoglycemic or hyperglycemic event was 90% for 60 mg/dL, 94% for 70 mg/dL, 99% for 180 mg/dL, and 98% for 240 mg/dL.

Sensor survival was 96% through day 120, 94% at day 150, and 90% at day 180.

For the secondary SBA sensor, overall accuracy on the basis of glucose range was 87.3% with the lowest accuracy (84.6%) in the range 81 to 180 mg/dL and highest (94.1%) in the 351 to 400 mg/dL range. The study period accuracy ranged from 78.6% on day 1 to 93.1% on days 90 and 180.

For the primary sensor, 20.4% of patients reported an adverse event, most of which were dermatologic (11.6%) followed by hematologic (7.7%) or neurologic (3.9%). For SBA sensors, 23.3% of patients reported an adverse event. Among all sensors, 1.1% were associated with an infection at the incision location.

This study was limited by its lack of diversity among study participants.

This study found that the next-generation long-term implantable Eversense CGM system had sustained accuracy and was safe up to 180 days.

Disclosure: Multiple authors declared affiliations with the biotech or pharmaceutical industries. Please refer to the original article for a full list of disclosures.


Garg SK, Liljenquist D, Bode B, et al. Evaluation of accuracy and safety of the next-generation up to 180-day long-term implantable Eversense continuous glucose monitoring system: the PROMISE study. Diabetes Technol Ther. 2022;24(2):84-92. doi:10.1089/dia.2021.0182