OBJECTIVE: Chronic hyperglycemia may shift physiological and perceptual thresholds upward, such that guideline-defined glucose targets feel aversive. We compared time in range (TIR) (70-180 mg/dL) with time in personal range (TIPR) (mean glucose ± 50 mg/dL) to determine whether daily symptoms, functioning, and diabetes-specific outcomes align more closely with guideline-based versus personal glucose ranges. RESEARCH DESIGN AND METHODS: Adults with type 1 diabetes completed 14 days of blinded continuous glucose monitoring (CGM), with ecological momentary assessments (EMAs) and mobile cognitive testing six times daily. For each 3-h interval preceding an EMA prompt, we calculated the percentage of time in guideline-defined and personal ranges. We estimated within-person correlations and regression models evaluating the incremental predictive effects of TIPR over TIR. Analyses were repeated stratified by personal (unblinded) CGM use. RESULTS: Analyses included 161 participants (mean ± SD 41.1 ± 14.8 years old; 55% female; 41% Hispanic, 30% non-Hispanic White, 14% non-Hispanic Black). Compared with TIR, TIPR was more consistently associated with improved pain, fatigue, activity demands, and perceptual speed, whereas TIR was more strongly associated with better diabetes-specific self-evaluations (diabetes distress and self-care). Glucose metrics showed minimal associations with stress and negative affect, and TIPR showed modest associations with positive affect. In models including both predictors, TIPR explained unique variance beyond TIR for several outcomes. Associations between glucose metrics and diabetes-specific outcomes were stronger among CGM users than nonusers. CONCLUSIONS: Personal glucose ranges capture aspects of lived experience not fully reflected by guideline targets, supporting TIPR as a complementary metric for psychosocially informed, person-centered care.
Pyatak et al. (2026) studied this question.