(637) Evaluating Acute Renal Failure as an Indicator of Severe Maternal Morbidity

Acute renal failure (ARF) is among the most common indicators of the CDC severe maternal morbidity (SMM) composite. There is a wide range of clinical circumstances that may trigger a diagnosis code for ARF, including transient acute kidney injury (AKI) which typically has minimal implications for a patient’s clinical care and does not represent a severely morbid outcome. The purpose of this study was to characterize the etiologies and severity of ARF experienced by patients with this SMM indicator during the delivery admission. 

Study Design:

This cross-sectional study conducted in a single tertiary hospital included all patients delivered 1/1/2022-6/30/2024 > 22 weeks with ARF as defined by the CDC SMM composite. Patient demographics, clinical histories, obstetric outcomes, and the details of their acute renal condition were derived from the electronic health record via detailed chart review and evaluated descriptively. They were also compared in bivariable analysis among patients with and without concurrent hypertensive disorders of pregnancy (HDP). 

Results:

88 total patients were included (out of 13,685 total deliveries during the study period; 0.64%). Of these, only 40 (45%) had a clear suspected etiology of ARF described in the chart  (Figure 1). The leading suspected etiology was acute blood loss, followed by obstructive uropathy. The majority of patients had HDP (76%) though there were no differences in the examined characteristics among those with and without HDP other than gestational age at delivery (Table 1). Median highest serum creatinine was 1.2 mg/dL in both groups (IQR 1.1-1.4) and 18 patients (20.5%) had a creatinine above 1.5 mg/dL at any point during the hospitalization. A minority of patients required higher level care for ARF including nephrology consult or dialysis or had additional SMM indicators.

Conclusion:

These data highlight that the majority of patients with ARF according to the CDC SMM criteria have minor AKI without other renal morbidity. Including ARF  as an indicator for SMM may distort this composite outcome.