506: A population-based definition for severe proteinuria and its association with adverse outcomes in preeclampsia

Abstract

In preeclampsia (PE), the association between the degree of proteinuria and adverse outcomes remains unclear. The historical definition of severe proteinuria (>5g protein in a 24-hr urine collection) was likely too restrictive as few women exceed that mark. We sought to define severe proteinuria in our study population and to determine if its presence associates with adverse outcomes in PE. Retrospective cohort study of subjects delivered ≥23 weeks’ gestation at a single institution (Oct ‘13 – Apr ‘18) with a hypertensive disorder of pregnancy [chronic hypertension, gestational hypertension, PE, or preeclampsia with severe features (PE-SF)]. Subjects were identified by ICD-9/ICD-10 discharge codes, followed by individual chart review. From study subjects, the 90th percentile for protein in a 24-hr urine collection or protein/creatinine (P/C) ratio from a random (spot) specimen was determined. These values were used as the cut- point to define severe proteinuria in our analytic sample. We then compared adverse neonatal and maternal outcomes between those with and without severe proteinuria. Data were analyzed by Fisher’s exact, t-test, and logistic regression, with α=0.05. From 10,833 deliveries, 1,487 (13.7%) were classified with a hypertensive disorder of pregnancy. The 90th percentile for urine protein on a 24-hr specimen was 1,580 mg, and for urine P/C ratio on a random specimen was 1.75. Among 396 women with PE-SF, 78 (19.7%) had severe proteinuria >90th percentile. Subjects with severe proteinuria were younger, had a lower BMI, more likely to be nulliparous and covered by public insurance compared to PE-SF subjects without severe proteinuria (Table 1). Severe proteinuria was associated with more severe systolic and diastolic blood pressures (p<0.001 and p=0.047, respectively) as well as any severe feature of PE (p=0.016). They also had worse composite neonatal outcomes (p=<0.001) which remained significant after multivariable adjustment (aOR: 2.92, p<0.001) (Table 2). Most notably, the odds of preterm birth <34 weeks was increased 4.8 times in women with PE-SF and severe proteinuria compared to those with PE-SF but without severe proteinuria (p<0.001). We demonstrate that severe proteinuria, as defined by population-based data, shows a strong association with adverse neonatal outcomes and preterm birth in women with preeclampsia.View Large Image Figure ViewerDownload Hi-res image Download (PPT)