Racial disparities in pregnancy-related acute kidney injury

Introduction: Pregnancy-related acute kidney injury (PR-AKI) is increasing in the United States. PR-AKI is associated with adverse maternal outcomes. Disparities in racial/ethnic differences in PR-AKI by race have not been studied. Methods: This was a retrospective cohort study utilizing the National Inpatient Sample (NIS) from 2005-2015. We identified patients who were admitted for a pregnancy-related diagnosis using the Neomat variable provided by the NIS database that indicates the presence of a maternal or neonatal diagnosis code or procedure code. PR-AKI was identified utilizing ICD codes. Survey logistic regression was used for multivariable analysis adjusting for age, medical comorbidities, socioeconomic factors, and hospital/admission factors. Results: From 48,316,430 maternal hospitalizations, 34,001 (0.07%) were complicated by PR-AKI. Hospitalizations for PR-AKI increased from 3.5/10,000 hospitalizations in 2005 to 11.8/10,000 hospitalizations in 2015 with the largest increase seen in patients aged ≥ 35 and black patients. PR-AKI was associated with higher odds of miscarriage (adjusted odds ratio (aOR) 1.64, 95% CI 1.34-2.07) and mortality (aOR 1.53, 95% CI 1.25-1.88). After adjustment for age, medical comorbidities, and socioeconomic factors, blacks were more likely than whites to develop PR-AKI (aOR 1.17, 95% CI 1.04-1.33). On subgroup analyses in hospitalizations of patients with PR-AKI, blacks and Hispanics were more likely to have preeclampsia/eclampsia compared to whites (aOR 1.29, 95% CI 1.01 - 1.65 and aOR 1.69, 95% CI 1.23-2.31 respectively). Increased odds of mortality in PR-AKI compared to whites were only seen in black patients (aOR 1.61, 95% CI 1.02-2.55). Conclusion: The incidence of PR-AKI has increased and the largest increase was seen in older patients and black patients. PR-AKI is associated with miscarriages, adverse discharge from hospital, and mortality. Black and Hispanic patients with PR-AKI were more likely to have adverse outcomes than white patients. Further research is needed to identify factors contributing to these discrepancies.