Sex-Related Differences in Incidence and Prevalence and Outcomes of AKI

Background: Acute kidney injury (AKI) is a common condition affecting hospitalized patients. While male sex has been correlated as a risk factor for AKI, our aim was to evaluate if age-related sex disparities exist in AKI development and post-AKI outcomes. Methods: Using the Stony Brook University (SBU) and US Collaborative TriNetX Networks, inpatient encounters for both male and female sex between January 2014 and December 2023 were queried for individuals 0-89 years of age. Outcomes of AKI were assessed using ICD-10 billing codes. Short- and long-term outcomes were defined as having AKI within 90 days and 1 year of inpatient encounter, respectively. Mortality was assessed for within 1 year of reaching the short-term or long-term outcome. Propensity score matching was utilized to match SBU cohorts based on race, ethnicity, and comorbidities (HTN, DM, CVD, Obesity). Hormone replacement therapy (HRT) was defined as use of estrogens, progestins, gonadotropins, or ICD-10 code for HRT. Absolute risk difference (RD), risk ratio (RR), and hazard ratio (HR) comparing risk of AKI/mortality were measured. Results: The overall risk of developing AKI was greater in males vs females in both SBU (short term RD: 2.063%, p < 0.0001; long term RD: 2.332% p < 0.0001) and US (short term RD: 1.538% p < 0.0001; long term RD: 1.749% p < 0.0001) cohorts. In age-related analyses, the RR of AKI was highest in the 30-39 decade of age in the SBU cohort for both short-term (RR: 3.316) and long-term (RR: 2.778) outcomes, while US cohort showed highest risk ratio at 20-29 in short term (RR: 2.518) and 30-39 in long-term (RR: 2.498). AKI risk increased per decade of year in both males and females. In the SBU cohort, females exhibited higher risk of death within 1 year of AKI diagnosis, regardless of short-term (HR: 0.890, p = 0.006) or long-term (HR: 0.886, p = 0.001) AKI outcome. Females not on HRT also showed lower risk of developing AKI as compared to females on HRT both short-term (HR= 0.613, p <0.0001) and long-term (HR = 0.571, p <0.0001). Conclusion: Incidence and prevalence of AKI diagnosis is higher in males as compared to females across all age groups, with a peak in risk ratio noted at 30-39. However, females with AKI had higher risk of death as compared to males with AKI. The use of HRT did not mitigate the risk of AKI in females.