Prevalence of and Risk Factors for Chronic Kidney Disease of Unknown Aetiology in India

Abstract

Background: Studies in central America and Sri Lanka have reported a high burden of chronic kidney disease of unknown aetiology (CKDu). It is unknown whether CKDu occurs in other regions of the world and what the risk factors are. Methods: We estimated the glomerular filtration rate (eGFR) and the prevalence of eGFR below 60ml/min per 1.73m2 (eGFR<60) (a proxy definitions of CKDu) in 12,500 people without known risk factors for chronic kidney disease (diabetes or hypertension) or heavy proteinuria. Participants were enrolled in three population-based studies in urban and rural areas of Northern and Southern India between 2010-2014. Results: The mean eGFR was 105.0±17.8 ml/min per 1.73m2. The prevalence of eGFR<60 was 1.6% (95%CI=1.4-1.7), but this figure varied markedly between areas, being highest in rural areas of Southern Indian [4.8% (3.8-5.8)]. In Northern India, older age was the only risk factor associated with lower mean eGFR and eGFR<60 [regression coefficient (95%CI)=-0.94 (0.97 – 0.91); OR (95%CI)=1.10 (1.08-1.11)]. In Southern India, risk factors for lower mean eGFR and eGFR<60 were residence in a rural area [-7.78 (-8.69 - -6.86); 4.95 (2.61-9.39)], older age [-0.90 (-0.93 - -0.86); 1.06 (1.04-1.08)] and less education [-0.94 (-1.32 - -0.56); 0.67 (0.50-0.90) for each five years at school].Conclusions: Reduced eGFR that is not associated with traditional risk factors for CKD is common in rural settings of Southern India. This is the first population-based evidence, using standardised methods, which indicates that CKDu is present in India and is not confined to central America and Sri Lanka.