Heat Stress Nephropathy in CKD of Uncertain Etiology Hotspots of Bargarh District Odisha, India.

Introduction: Repeated heat exposure, physical exertion, and inadequate hydration can cause acute kidney injury (AKI), potentially progressing to chronic kidney disease (CKD). However, cohort-level research on heat stress as a contributing factor remains limited. This study investigates occupational heat exposure among farming communities in hotspot villages of Bargarh district, Odisha, India. Methods: A cross-sectional study of 1136 participants was conducted in Bargarh district to assess heat stress nephropathy among agricultural workers. Based on Sri Lankan criteria, heat stress nephropathy was defined by albumin-creatinine ratio ≥ 30 mg/g, no known CKD causes, urine specific gravity ≥ 1.03, and signs of tubulointerstitial nephritis. Heat stress index, serological tests, and urine analyses were performed using standard protocols. Serum and urine levels of heat shock protein (HSP)27 and HSP70 were measured via enzyme-linked immunosorbent assay. Renal biopsies were conducted on 8 selected patients for histopathological evaluation. Results: Out of the total screened population, 157 potential cases of heat stress nephropathy were identified, with 63.3% of affected individuals being farmers. The Attabira block recorded the highest heat stress index and the most CKD of uncertain etiology (CKDu) cases among farmers. Markers of dehydration, including the simplified wet bulb globe temperature (sWBGT) index, urine specific gravity (64.09%), albumin-to-creatinine ratio (5.88%), blood urea nitrogen (BUN, 63.2%), and HSP, were significantly elevated in the farming population compared with the control group. Renal histopathological analysis revealed tubulointerstitial nephritis with signs of fibrosis. Conclusion: Heat stress nephropathy was commonly observed among individuals involved in farming activities. Renal histopathological analysis, along with elevated levels of HSP70 and HSP27 confirmed the diagnosis.