Effects of a device-measured physical activity intervention on visual outcomes, including contrast sensitivity, and glycaemic control in individuals with abnormal glucose tolerance: a pilot randomised trial post-CarMeR study

Abstract Background Abnormal glucose tolerance (AGT), a summary term for prediabetes and diabetes, is a significant public health concern in sub-Saharan Africa, where diabetes-related complications like retinopathy are underdiagnosed. Lifestyle interventions, specifically physical activity, offer a cost-effective approach to improve glycaemic and visual outcomes in resource-limited settings. However, feasibility data on the effectiveness of these interventions in low-resource settings are limited. This pilot randomised controlled trial (RCT) assessed the feasibility of a 12-week device-measured physical activity intervention on glycaemic control and visual functioning among individuals newly diagnosed with AGT in Ghana. Methods Twenty-four participants were randomly assigned to intervention and control groups, with the intervention group receiving a progressive physical activity regimen monitored by smartphone sensors and mobile apps, while the control group received general health education. The primary outcomes were feasibility measures, including recruitment, retention, adherence, and adverse events. Secondary outcomes included clinical measures of visual function (visual acuity, contrast sensitivity, central visual field, and visual disability index) and glycaemic control [glycated haemoglobin (HbA1c), fasting blood sugar (FBS), fasting plasma glucose (FPG), 2-h plasma glucose level (2hPG)]. Results The trial demonstrated good feasibility with 93.3% target sample attainment, 85.7% retention, and no adverse events. Participants in the intervention group achieved an average of 77 min of objectively measured physical activity daily. Regarding secondary clinical outcomes, participants in the intervention group demonstrated a 1.18% reduction in HbA1c (95% CI, −1.65, −0.71) and improvements in contrast sensitivity in the right (Δ = 0.029; 95% CI, −0.11, 0.17) and left (Δ = 0.046; 95% CI, −0.09, 0.19) eyes. Conclusion This pilot study offers promising evidence for the feasibility of a technology-monitored physical activity intervention in improving glycaemic control and contrast sensitivity among community-dwelling individuals with AGT. Insights from this study will inform future practical and scalable physical activity interventions in resource-limited settings. Trial registration Pan African Clinical Trials Registry PACTR202409492459905. Registered on 16th September 2024.