Background
This systematic review seeks to employ a meta-analysis to evaluate the differential impacts of exercise interventions with high adherence versus those with low or uncertain adherence, following the American College of Sports Medicine (ACSM) guidelines, on factors such as glucose regulation and insulin sensitivity in prediabetic patients.
Methods
A thorough search was executed across databases such as PubMed, Embase, Web of Science, and the Cochrane Library from inception to September 1, 2025. We carried out a meta-analysis concentrating on exercise interventions among prediabetic patients. Only randomized controlled trials were included in our study. The meta-analyses determined WMDs for parameters such as fasting blood glucose (FBG), 2-hour plasma glucose (2hPG), glycated haemoglobin A1c (HbA1c), and homoeostasis model assessment of insulin resistance (HOMA-IR).
Results
There were 24 studies with a total of 1,480 participants. Compliance with the ACSM recommendations was categorised as 'high' in 9 studies and 'low or uncertain' in 15 studies. In the subgroup analysis comparing high compliance with ACSM recommendations to low or uncertain compliance, the results were as follows: FBG: -0.55 (95% CI: -1.01, -0.09) vs -0.42 (95% CI: -0.62, -0.21), 2hPG: -0.97 (95% CI: -1.48, -0.45) vs -0.70 (95% CI: -1.15, -0.25), HOMA-IR: -0.47 (95% CI: -0.81, -0.14) vs -0.50 (95% CI: -1.09, 0.08), HbA1c:-0.20 (95% CI: -0.50, 0.10) vs -0.29 (95% CI: -0.46, -0.12).
Conclusion
Subgroup analyses were conducted to evaluate whether intervention adherence modifies the metabolic benefits of exercise. Mean reductions in FBG, 2hPG, and HOMA-IR were numerically larger in participants with high, compared with low or uncertain, adherence, suggesting a possible dose-response relationship between adherence and glycaemic improvement. Conversely, HbA1c displayed a marginally greater reduction in the low-adherence stratum - an observation that contrasts with the pattern seen for the other glucose/insulin indices. This discrepancy may reflect greater analytical variability of HbA1c, differences in intervention duration, baseline imbalance, or heterogeneity in programme content and individual responsivity across adherence categories. Large-scale, long-term trials that standardise the measurement of adherence and the delivery of exercise interventions are needed to definitively clarify the association between adherence and metabolic outcome.