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

<b><i>Background:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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). <b><i>Conclusion:</i></b> 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.

**背景**：妊娠相关性急性肾损伤（Acute kidney injury, AKI）是一项公共卫生问题，与孕产妇及胎儿的发病率和死亡率密切相关。目前针对妊娠相关性AKI的临床结局与医疗服务利用情况，尤其是合并糖尿病的女性群体，尚缺乏充分研究。
**方法**：本研究利用2006年至2015年全国住院患者样本（Nationwide Inpatient Sample）的数据，纳入15~49岁女性的42,190,790例妊娠相关住院病例。我们分析了妊娠相关住院期间与AKI相关的影响因素（包括种族/族裔），以及AKI与住院死亡率、AKI与心血管（Cardiovascular, CV）事件之间的关联，并核算了妊娠相关性AKI住院病例的医疗费用支出。
**结果**：总体而言，妊娠相关住院病例中AKI的发生率为0.08%。校正回归分析显示，与2006年相比，2015年妊娠相关住院患者发生AKI的风险更高（比值比[Odds Ratio, OR]=2.20；95%置信区间[95% Confidence Interval, 95%CI]：1.89~2.55）；与20~25岁女性相比，36~40岁（OR=1.49；95%CI：1.36~1.64）及41~49岁女性（OR=2.12；95%CI：1.84~2.45）的AKI发生风险更高；与白人女性相比，黑人（OR=1.52；95%CI：1.40~1.65）及美洲原住民（OR=1.45；95%CI：1.10~1.91）的AKI发生风险更高；合并糖尿病的女性（OR=4.43；95%CI：4.04~4.86）的AKI发生风险显著高于无糖尿病女性。与未合并AKI的妊娠相关住院病例相比，合并AKI的病例住院死亡率（OR=13.50；95%CI：10.47~17.42）及CV事件发生风险（OR=9.74；95%CI：9.08~10.46）均显著升高。合并AKI的分娩住院病例的中位医疗费用显著高于未合并AKI者（分别为18072美元与4447美元）。
**结论**：近十年来，妊娠相关性AKI住院病例的发生率呈上升趋势。妊娠期间AKI发生风险升高的相关因素包括高龄、黑人及美洲原住民种族/族裔，以及合并糖尿病。与未合并AKI的妊娠相关住院病例相比，合并AKI者的住院死亡率与CV事件发生风险更高，且医疗服务利用程度也更高。