Probable Chronic Kidney Disease and Its Association with Extreme-Heat Exposure in Selected Local Government Areas of Yobe State, Northeastern Nigeria: A Community-Based Cross-Sectional Study with Hospital-Record Analysis

Background: Chronic kidney disease (CKD) of unknown cause has been reported in northern Yobe State, Nigeria, where extreme heat is common, but its relationship with climate has not been tested. Repeated heat stress and dehydration have been proposed as contributing mechanisms, and community-based data from sub-Saharan Africa remain scarce. Methods: We conducted a community-based cross-sectional study involving 1,200 adults recruited through cluster sampling from 24 communities across four local government areas (LGAs) in Yobe State: Bade, Nguru, Jakusko and Damaturu. Kidney abnormalities were assessed using estimated glomerular filtration rate (eGFR), calculated with the 2021 CKD-EPI equation, and urinary albumin-to-creatinine ratio (ACR). Participants were classified as having CKD-range abnormalities if eGFR was below 60 mL/min/1.73 m² and/or ACR was ≥30 mg/g on a single measurement. However, chronicity of at least three months was not established. Associations between individual outcomes and community-level extreme-heat exposure were assessed using generalized estimating equations (GEE), while annual LGA-level hospital presentations from 2014 to 2023 were examined using Poisson regression. Results: Overall, 166 of the 1,200 participants (13.8%; 95% CI: 12.0–15.9) had kidney abnormalities meeting the study's CKD criteria based on a single measurement, without confirmation of chronicity. The prevalence was highest in Bade (18.3%) and lowest in Damaturu (8.3%). Each additional 10 extreme-heat days per year was associated with 33% higher odds of CKD-range abnormalities (adjusted OR: 1.33; 95% CI: 1.14–1.55). Conclusion: Greater exposure to extreme-heat days was associated with higher odds of kidney abnormalities meeting the study's CKD criteria in the selected LGAs of Yobe State. However, the cross-sectional design and absence of repeat kidney-function measurements limit the interpretation of these findings. Longitudinal studies incorporating repeated kidney-function assessments and individual-level heat-exposure measurements are required to establish temporality and investigate potential causal relationships.