Correlation of Peripartum Acute Kidney Injury Severity With Obstetric Comorbidity Index Scores and Maternal Morbidity [ID 2683636

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INTRODUCTION: Risk stratification systems are increasingly used to predict obstetric complications. The Obstetric Comorbidity Index (OB-CMI) is one validated prediction tool, applying weighted scores to maternal and obstetric conditions. Although acute kidney injury (AKI) is a severe maternal morbidity, there is limited information on predicting AKI severity. We aimed to investigate the utility of OB-CMI scores and its specific comorbidities in predicting obstetric AKI severity, and the relationship of AKI severity and other maternal morbidity outcomes. METHODS: This was an IRB-exempt, retrospective cohort study of AKI cases (ICD-10 code N17.0-17.9) between January 2018 and December 2022 at a single academic institution with ∼6,000 births annually. Information was extracted via chart review. Cases were stratified by those meeting American College of Obstetricians and Gynecologists (ACOG)/Society for Maternal-Fetal Medicine (SMFM) criteria for severe renal injury. Those with unknown baseline Cr were assigned 0.7 (the 95th percentile Cr value at 39–40 weeks). Groups were compared based on admission OB-CMI scores and comorbidities, and maternal morbidity events using independent t-tests, χ2, and Fisher's exact as appropriate. RESULTS: Two hundred thirty cases were reviewed: 8.3% (19 cases) met ACOG/SMFM AKI criteria. There was no significant difference in mean OB-CMI scores (mean 3.8 versus 4.1; P=.782) or incidence of individual comorbidities between groups. Regarding other maternal morbidity events, ACOG/SMFM criteria AKI was significantly associated with other severe morbidity events (47.4% versus 12.3%; P<.001), including transfusion, disseminated intravascular coagulation, intubation, and intensive care unit admission. CONCLUSION: The OB-CMI score was poorly predictive of AKI severity; however, the occurrence of severe AKI by ACOG/SMFM criteria was associated with a 4-fold increased rate of co-occurring maternal morbidity events and a 2.5-fold increased rate of blood transfusion.