Austin—Patients who experience acute kidney injury (AKI) are at increased risk for short- and long-term mortality. Results of previous studies have revealed a higher risk of mortality among males with AKI; female sex has been shown to be protective in both the development of AKI and the AKI-related mortality risk. The majority of those studies utilize univariate analyses, without consideration of the effects of confounding factors. In animal models of ischemic AKI, female sex has also been shown to be protective.
Robert Adrah, MD, and Ladan Golestaneh, MD, conducted an analysis to test the hypothesis that female sex is protective against mortality related to AKI. They reported results of the analysis during a poster session at the NKF Spring Clinical Meetings in a poster titled Female Sex Protects against Mortality after an Episode of Acute Kidney Injury (AKI).
The researchers utilized Montefiore’s clinical database, Looking Glass™, to define a cohort of all hospitalized patients from January 2009 to November 2011, and selected patients without chronic kidney disease with a >10% difference in estimated glomerular filtration rate (eGFR) measured within the previous 6 months and upon admission.
Community-acquired AKI was defined using the two eGFR measurements according to criteria from the Acute Kidney Injury Network (AKIN). Bivariate analysis and log-rank testing were used to examine the associations between gender, community-acquired AKI, and 2-year mortality. The researchers examined the robustness of the association of gender and AKI-related mortality with Cox regression (stepwise forward selection).
The total cohort included 19,571 patients. Of those, 33% had AKIN stage 1 AKI, 6.5% had AKIN stage 2 AKI, and 2.5% had AKIN stage 3 AKI. Compared with the men in the cohort, women in the cohort were older, more commonly black, had lower socioeconomic status, lower Charlson scores, and had lower length of stay during the index hospitalization. Women also tended to have less severe illness during hospitalization.
Log-rank testing showed the association between female sex and mortality to be significant. The hazard ratio for mortality was 0.89 (95% confidence interval, 0.80-1.00) for women compared with men. The strength of the protective effect of female sex on mortality was attenuated by the Charlson score and the severity of illness.
In conclusion, the researchers said, “In patients with community-acquired AKI, female gender was protective against mortality after an episode of AKI. Cox modeling showed that females have less severe disease with their diagnosis of community-acquired AKI, which explains some, but not all, of this protective effect,” the researchers said.
Source: Adrah R, Golestaneh L. Female sex protects against mortality after an episode of acute kidney injury (AKI). Abstract of a poster presented at the National Kidney Foundation 2018 Spring Clinical Meetings, April 10-14, 2018, Austin, Texas.