JMIR Publications

ABSTRACT

Background:

Poor glycaemic control in primary care increases the risk of microvascular and macrovascular complications among people with type 2 diabetes mellitus (T2DM). Evidence suggests that continuous glucose monitoring (CGM) improves glycated haemoglobin (HbA1c), increases time in range (TIR), reduces glycaemic variability and lowers hypoglycaemic events but data on feasibility in Indian public primary care, especially combined with low-carbohydrate dietary advice (<130g/day), remains limited.

Objective:

To assess the feasibility of implementing CGM in urban primary health centres (UPHCs) and to evaluate the effectiveness of a low-carbohydrate dietary intervention among people with T2DM by using CGM-derived metrics and adverse events.

Methods:

This was a facility based two arm parallel cluster-randomised trial conducted between April and June 2025 in UPHCs of the Greater Chennai Corporation, Chennai, India. Approximately 10% of the main trial participants (N=320) were selected for CGM yielding 37 participants in this sub-study (20 intervention, 17 control). This sub-study design isolates and evaluates the incremental clinical efficacy of the structured low-carbohydrate diet (LCD) counsel against standard national nutritional care. The intervention arm received CGM plus structured low carbohydrate diet advice, while the control arm received CGM plus standard care as per the National Programme for Prevention and Control of Non Communicable Diseases guidelines. Participants in both arms shared images of all meals via WhatsApp during 14 days of CGM use. Baseline sociodemographic, behavioural, and clinical data were collected using a semi structured questionnaire. After 14 days, CGM metrics, adverse events, self reported self management changes, and feedback were recorded. Continuous variables were summarised as mean (standard deviation (SD)) and categorical variables as frequencies and proportions; group differences were assessed using chi square or fisher exact tests and independent sample t tests.

Results:

Participants had a mean age of 55.2 (SD 9.8) years; 55.5% (n=22) were male and most reported physical inactivity (97.2%, n=35) and poor dietary adherence (88.9%, n=32) at baseline. Nearly all participants (97.1%, n=33) reported that CGM positively impacted diabetes self management. Adverse events occurred in 24.3% (n=9), including local skin reactions (10.8%), systemic symptoms (5.4%), and psychological or behavioural concerns (8.1%). Overall, 59.5% (n=22; 95% CI: 42.6-74.3) maintained glucose within TIR 70–180 mg/dL; this proportion was higher in the intervention than control arm (75.0% [n=15; 95% CI: 51.3-89.5] vs 41.2% [n=7; 95% CI: 20.5-65.5]; p=0.04). A total of 78.4% (n=29; 95% CI: 61.7-89.1) had less than 1% of readings below 54 mg/dL, with higher proportions in the intervention than control arm (90.0% [n=18; 95% CI: 66.5-97.6] vs 64.7% [n=11; 95% CI: 39.6-83.7]; p=0.11). All intervention participants and 86.7% (n=15; 95% CI: 61.9-97.2) in the control arm achieved coefficient of variation ≤36%, indicating stable glucose levels (p=0.21).

Conclusions:

Embedding CGM with low carbohydrate dietary counselling in Indian public primary care was feasible from a patient acceptability standpoint and improved TIR compared with CGM plus standard care in this small CGM subset of a cluster randomised trial. Policy measures to subsidise CGM for high risk T2DM patients in UPHCs and larger trials, including cost effectiveness evaluations, are warranted Clinical Trial: The trial was registered in Clinical Trials Registry-India (CTRI/2024/02/062202).