Chronic kidney disease of unknown aetiology: A comprehensive review of a global public health problem

The term chronic kidney disease of unknown aetiology (CKDu) refers to chronic kidney disease (CKD) in the absence of diabetes, long-standing hypertension, glomerulonephritis, obstructive uropathy or other apparent causes. An increasing number of CKDu cases have been reported from Latin America, Sri Lanka, India and others over the last two decades. These regional nephropathies share the following common attributes: (a) they affect low-to-middle income countries with tropical climates, (b) involve predominantly rural agricultural communities, (c) male predilection, (d) absence of significant proteinuria and hypertension, and (e) chronic tubulointerstitial nephritis on kidney biopsy. The current body of literature suggests that CKDu may be caused by heat stress, agrochemicals, contaminated drinking water or heavy metals; however, considerable regional disparities in CKDu research make it difficult to establish a common causal link. In the absence of a definite aetiology, specific preventive and therapeutic interventions are lacking. Improvement of working conditions of farmers and labourers, provision of safe drinking water and changes in agricultural practices are some of the measures that have been implemented; however, there is lack of data to assess their impact on the incidence and progression of CKDu. There is a need for a concerted global effort to address the current knowledge gaps, and to develop effective and sustainable strategies to tackle this devastating disease.