Real-world accuracy, extended-wear performance, and user satisfaction with a novel 21-day continuous glucose monitoring system in pediatric type 1 diabetes

Introduction

Extended-wear continuous glucose monitoring (CGM) may reduce device burden in pediatric type 1 diabetes (T1D), but accuracy must be maintained throughout the labeled sensor lifetime. This study was designed to evaluate device performance under routine clinical conditions rather than under controlled laboratory conditions. We evaluated the real-world accuracy, 21-day wear-period performance, glycemic profile, and user satisfaction of the Instara-1 21-day CGM system. Research design and methods: CGM readings were paired with the temporally nearest capillary reference glucose value within the predefined matching window. Sensor accuracy was assessed by calculating the mean absolute relative difference (MARD) using paired capillary fingerstick blood glucose measurements as the reference. The primary accuracy analysis used the ±10-minute matching window after exclusion of values flagged as >50% outliers. Accuracy was assessed using MARD, ±20/20 agreement, Bland-Altman analysis in both absolute and relative percentage terms, daily MARD across 21 days, and glucose-range stratification. CGM-derived glycemic metrics were summarized in 52 participants, and user satisfaction was evaluated with a Turkish questionnaire validated for children and adolescents.