Comparative Performance Analysis of Manual and Updated Optional Calibration Algorithms for the CareSens Air CGM System.

Background: The CE-marked CareSens Air continuous glucose monitoring (CGM) system (CSAir) features a 15-day sensor lifetime, a 2-hour warm-up period and mandatory manual calibrations. During subsequent product development, the algorithm was updated to reduce the warm-up period to 30 minutes and make user-entered calibrations optional. This study compared the CSAir's performance between the manual and updated algorithms.

Methods: Thirty adults with diabetes wore three CSAir sensors on their upper arms for 15 days. The study included three in-clinic sessions with capillary comparator measurements at 15-minute intervals over seven hours and glucose manipulation in the hypo- or hyperglycemic range. Point accuracy was assessed via mean absolute relative difference (MARD), 20/20 agreement rates (AR) stratified by BG range, and sensor wear time. Further evaluations included clinical point accuracy, alert reliability, technical reliability, safety and user satisfaction.

Results: The CSAir's updated algorithm exhibited improved accuracy compared with the manual calibration algorithm, with a total 20/20 AR of 93.9% (vs 90.1%) and an MARD of 8.7% (vs 9.9%). Accuracy remained stable across measurement ranges and sensor lifetime. Diabetes Technology Society Error Grid analysis revealed high clinical accuracy, with 88.0% and 92.4% of data pairs in zone A for the manual and updated algorithms, respectively. The estimated survival probability was 88.8%. Participants reported positive user satisfaction. No safety concerns were identified.

Conclusions: Both algorithms of CSAir demonstrated robust performance and reliability with improved accuracy with the updated version. The study results of the CSAir suggest its suitability for nonadjunctive use.