Risk of progression to type 2 diabetes or regression to normoglycaemia among Ghanaians with prediabetes living in Ghana and the Netherlands: The RODAM prospective study

Introduction: Evidence shows that ethnicity affects the risk of progression of prediabetes to type 2 diabetes(T2D) or regression to normoglycaemia However, little is known about progression rates among sub-Saharan African populations or whether geographical context affects risk variations. We compared the risk of progression to T2D or regression to normoglycemia in West Africans with prediabetes living in Africa and their migrant compatriots living in Europe. Methods: We analysed data from 615 Ghanaians with prediabetes at baseline (245 in Ghana/370 in Amsterdam) in the prospective RODAM cohort with an average follow-up of 6.7 years. Prediabetes was defined according to the WHO criteria. Incidence risk ratios for progression to T2D and regression to normoglycaemia were calculated with adjustment for age, sex, follow-up duration, socioeconomic status and baseline BMI and fasting plasma glucose. Results: Overall, the cumulative incidences of T2D and normoglycaemia from prediabetes were 12.6% and 28.9%, respectively. While the proportions of individuals who progressed to T2D did not differ between non-migrants and migrants (16.0% vs. 10.9%, p-value = 0.108), the proportion who regressed to normoglycaemia was higher in non-migrants (51.5% vs. 17.1%, p < 0.001) with an incident risk ratio of 3.48 (95% CI 2.39–5.05, p < 0.001) in the fully adjusted model. However, the risk of progression of prediabetes to T2D remained similar in the two groups after full adjustment [1.20 (0.71–2.05), 0.498]. Conclusions: Among Ghanaians with prediabetes, regression to normoglycaemia was more frequent than progression to T2D, and more likely in non-migrants than in migrants. Future studies could identify factors underlying the higher rates of regression to normoglycaemia in non-migrants to improve outcomes in individuals with prediabetes.