Estimating the Association Between Outdoor Temperature and Acute Kidney Injury Using Alternative Case Definitions.

Abstract

This study aimed to improve estimates of the association between acute kidney injury (AKI) and ambient heat exposure through better case ascertainment and by isolating community-acquired AKI. We conducted a case-crossover study using data on AKI-related emergency department (ED) visits in Atlanta. Daymet meteorology was used to assess exposure. We compared effect estimates for seven approaches (definitions) for identifying AKI. There were between 5868 and 64,269 AKI cases depending on the definition. Higher temperatures were associated with AKI for all case definitions. Associations were strongest for cases with an ICD-coded AKI as a primary diagnosis (OR, 1.15; 95% CI, 1.01-1.31). We also observed significant ( P < 0.05) heat associations among cases identified using laboratory results but without an ICD-coded AKI diagnosis. Many AKI cases are not diagnosed; these cases are associated with heat.