Effect of Exercise Versus Metformin among Nigerians with Prediabetes: A Randomised Controlled Trial

Prediabetes is an important risk factor for the development of type 2 diabetes and is common in Nigeria. Prediabetes often progresses to type 2 diabetes but effective intervention can reverse the carbohydrate intolerance associated with the condition. No studies have been reported among Nigerians on the natural outcome or effect of intervention in prediabetes.

To determine and compare the effect of moderate exercise and metformin on glucose tolerance among the participants with prediabetes.

Using a randomized placebo-controlled design, 54 Nigerians with prediabetes were selected using simple random sampling. They were offered treatment with metformin, moderate exercise, or placebo and followed up for 12 weeks. Plasma glucose levels were assessed before and after the interventions and the outcome was compared.

Forty-nine participants with prediabetes completed the study. Compared to placebo the exercise group had a significant decrease in glycaemic level from the baseline, FPG=5.1mmol/L (6.4% reduction) and 2HPGL=7.6mm/L (20.5% reduction) p-value<0.05. The metformin group also had a significant decrease in glycaemic level from the baseline, FPG=5.1mmol/L (13.3% reduction) and 2HPGL=7.9mmol/L (12.4% reduction) p-value<0.05. Diabetes risk reduction for exercise and metformin interventions were 50% and 40%respectively.

Among Nigerians with prediabetes, moderate exercise, and metformin interventions have significantly higher efficacy than placebo in improving glucose tolerance. However, moderate exercise and metformin have comparable efficacy in improving glucose tolerance and diabetes risk reduction. Participants in this study need to be followed up for a longer period to assess the long-term effects of these interventions.