Supplementary Material for: Pregnancy-Related Acute Kidney Injury in the United States: Clinical Outcomes and Health Care Utilization

Background: Acute kidney injury (AKI) during pregnancy is a public health problem and is associated with maternal and fetal morbidity and mortality. Clinical outcomes and health care utilization in pregnancy-related AKI, especially in women with diabetes, are not well studied. Methods: Using data from the 2006 to 2015 Nationwide Inpatient Sample, we identified 42,190,790 pregnancy-related hospitalizations in women aged 15–49 years. We determined factors associated with AKI, including race/ethnicity, and associations between AKI and inpatient mortality, and between AKI and cardiovascular (CV) events, during pregnancy-related hospitalizations. We calculated health care expenditures from pregnancy-related AKI hospitalizations. Results: Overall, the rate of AKI during pregnancy-related hospitalizations was 0.08%. In the adjusted regression analysis, a higher likelihood of AKI during pregnancy-related hospitalizations was seen in 2015 (OR 2.20; 95% CI 1.89–2.55) than in 2006; in older women aged 36–40 years (OR 1.49; 95% CI 1.36–1.64) and 41–49 years (OR 2.12; 95% CI 1.84–2.45) than in women aged 20–25 years; in blacks (OR 1.52; 95% CI 1.40–1.65) and Native Americans (OR 1.45; 95% CI 1.10–1.91) than in whites, and in diabetic women (OR 4.43; 95% CI 4.04–4.86) than in those without diabetes. Pregnancy-related hospitalizations with AKI were associated with a higher likelihood of inpatient mortality (OR 13.50; 95% CI 10.47–17.42) and CV events (OR 9.74; 95% CI 9.08–10.46) than were hospitalizations with no AKI. The median cost was higher for a delivery hospitalization with AKI than without AKI (USD 18,072 vs. 4,447). Conclusion: The rates of pregnancy-related AKI hospitalizations have increased during the last decade. Factors associated with a higher likelihood of AKI during pregnancy included older age, black and Native American race/ethnicity, and diabetes. Hospitalizations with pregnancy-related AKI have an increased risk of inpatient mortality and CV events, and a higher health care utilization than do those without AKI.