Background: Chronic kidney disease (CKD) is a major burden among sub-Saharan African (SSA) populations. However, differences in CKD prevalence between rural and urban settings in Africa, and upon migration to Europe are unknown. We therefore assessed the differences in CKD prevalence among homogenous SSA population (Ghanaians) residing in rural and urban Ghana and in three European cities, and whether conventional risk factors of CKD explained the observed differences. Furthermore, we assessed whether the prevalence of CKD varied among individuals with hypertension and diabetes compared with individuals without these conditions.
Methods: For this analysis, data from Research on Obesity & Diabetes among African Migrants (RODAM), a multi-centre cross-sectional study, were used. The study included a random sample of 5607 adult Ghanaians living in Europe (1465 Amsterdam, 577 Berlin, 1041 London) and Ghana (1445 urban and 1079 rural) aged 25-70 years. CKD status was defined according to severity of kidney disease using the combination of glomerular filtration rate (G1-G5) and albuminuria (A1-A3) levels as defined by the 2012 Kidney Disease: Improving Global Outcomes severity classification. Comparisons among sites were made using logistic regression analysis.
Results: CKD prevalence was lower in Ghanaians living in Europe (10.1%) compared with their compatriots living in Ghana (13.3%) even after adjustment for age, sex and conventional risk factors of CKD [adjusted odds ratio (OR) = 0.70, 95% confidence interval (CI) 0.56-0.88, P = 0.002]. CKD prevalence was markedly lower among Ghanaian migrants with hypertension (adjusted OR = 0.54, 0.44-0.76, P = 0.001) and diabetes (adjusted OR = 0.37, 0.22-0.62, P = 0.001) compared with non-migrant Ghanaians with hypertension and diabetes. No significant differences in CKD prevalence was observed among non-migrant Ghanaians and migrant Ghanaians with no hypertension and diabetes. Among Ghanaian residents in Europe, the odds of CKD were lower in Amsterdam than in Berlin, while among Ghanaian residents in Ghana, the odds of CKD were lower in rural Ghana (adjusted OR = 0.68, 95% CI 0.53-0.88, P = 0.004) than in urban Ghana, but these difference were explained by conventional risk factors.
Conclusion: Our study shows important differences in CKD prevalence among Ghanaians living in Europe compared with those living in Ghana, independent of conventional risk factors, with marked differences among those with hypertension and diabetes. Further research is needed to identify factors that might explain the observed difference across sites to implement interventions to reduce the high burden of CKD, especially in rural and urban Ghana.