Acute-phase reactants as predictors of chronic kidney disease incidence in Africans: the population-based prospective...

Chronic kidney disease (CKD) and chronic inflammation are highly prevalent in African populations, yet their relationship remains understudied. We examined the association between acute-phase reactants (C-reactive protein and ferritin) as markers of acute and chronic inflammation and the incidence of CKD 6 years later in a prospective Ghanaian population-based cohort.

Data from the prospective Research on Obesity and Diabetes among African Migrants (RODAM-Pros) cohort were analysed and included participants living in rural and urban Ghana and Ghanaian migrants in the Netherlands. Acute-phase reactants were assessed between 2012 and 2015, while CKD incidence was assessed between 2019 and 2021 by using the race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation. Robust Poisson regression models adjusted for potential confounders were used to assess associations. We explored interactions with age, sex, education, and geographical location, and stratified C-reactive protein (CRP) analyses by using established clinical cutoffs. The role of ferritin as an iron-storage marker was also evaluated.

Among 1435 participants, the baseline CRP was not associated with CKD incidence at follow-up [adjusted incidence rate ratio (aIRR) 1.02; 95% confidence interval (CI): 0.84-1.15]. Higher ferritin levels were associated with increased CKD risk (aIRR 3.53; 95% CI: 2.42-5.01) and albuminuria (aIRR 4.22; 95% CI: 2.87-6.10), but not with reduced estimated glomerular filtration rate (aIRR 0.99; 95% CI: 0.92-1.05). No effect modification was observed by age, sex, education, or geographical location. We found no evidence that iron overload or deficiency contributed to the ferritin-CKD relationship.

Elevated ferritin levels, but not CRP levels, were associated with future CKD risk in Ghanaians. Multi-population prospective studies with repeated ferritin measurements are needed to better understand the links between ferritin, iron status, and CKD in African populations.