Seasonal variations in acute kidney injury incidence and outcomes: a multicenter prospective observational study highlighting socioeconomic disparities

Kuwait experiences cool winters and hot summers. We evaluated the impact of ambient temperature in these two seasons on acute kidney injury (AKI) incidence and outcomes, and assessed difference between Kuwaitis and non-Kuwaitis. Clinical and 30-day outcome data from AKI patients who were admitted to seven public hospitals during winter and summer of 2021 were prospectively collected. Total number of AKI cases during both seasons was 1,493. Incidence was same in both seasons (50.0% each). Kuwaitis accounted for 56.7% of cases. Most AKI cases for Kuwaitis occurred in winter (52.4%), while most for non-Kuwaitis occurred in summer (53.2%). AKI patients in winter were significantly older (64.8 vs. 62.0 years, <i>p</i> = 0.001), had lower baseline eGFR (57.7 vs. 69.4 mL/min/1.73 m², <i>p</i> &lt; 0.001), and had more cardiovascular (60.1% vs. 50.6%, <i>p</i> &lt; 0.001), and chronic kidney diseases (59.3% vs. 43.6%, <i>p</i> &lt; 0.001). Fluid utilization was higher in summer (83.1% vs. 75.3%, <i>p</i> &lt; 0.001). No difference in mechanical ventilation and dialysis reported. Dialysis utilized slightly more frequently in summer (24.8% vs. 27.3%, <i>p</i> = 0.6), with significantly higher dialysis utilization for non-Kuwaitis in summer (30.6% vs. 23.0% for Kuwaitis, <i>p</i> &lt; 0.001). Mortality rate was 26.1%, and complete kidney recovery occurred in 56.1% of cases with no difference between groups. No seasonal variations in AKI incidence, dialysis need, or mortality rate. In winter, AKI occurred more in older with more comorbidities among Kuwaitis but better socioeconomically, while in summer, AKI occurred more in younger, healthier non-Kuwaitis but socioeconomically disadvantaged. This study attempts to describe the variation in the incidence rates and the outcomes of acute kidney injury in Kuwait, which has a very hot summer and a cool winter. We found no difference in the incidence or outcome of acute kidney injury between the hot summer months and the cool winter months; however, we found acute kidney injury to affect the younger and healthier non-Kuwaitis more frequently in the summer and the older Kuwaitis who have more comorbidities more frequently in the winter. We also found that dialysis was more frequently needed in the summer, especially for non-Kuwaitis.