Hypertensive (HTN) disorders during pregnancy have been shown to increase risk for severe maternal morbidity (SMM) in a tertiary care center. The objective was to evaluate the association between HTN disorders and SMM in a large, population-based cohort without referral bias. We hypothesized that there would be a dose- response relationship between HTN and SMM and that this association would be modified by race/ethnicity. We performed a retrospective cohort study, analyzing de-identified patient-level rates of SMM diagnoses and procedures for women who delivered at all non-military hospitals in Washington state from 10/2015- 9/2016. Data were obtained from the Washington State Comprehensive Hospital Abstract Reporting System (CHARS) which includes inpatient diagnosis, procedure, and discharge information derived from hospital billing systems. SMM and HTN disorders were determined from pre-specified International Classification of Disease diagnosis and procedure codes. Clinical and demographic information was compared by SMM. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to evaluate the association of HTN disorders and SMM. Of 76,965 deliveries in 61 hospitals, 983 patients (1.3%) had SMM diagnoses or procedures. 533 patients (0.7%) had transfusion only. Women with any HTN disorder differed compared to those without by age, race/ethnicity, multiple gestation, preterm delivery, diabetes, and mode of delivery. Women with any HTN disorder had a significantly higher risk of experiencing SMM compared to women without (3.5 vs. 1.0%, OR 3.7, 95% CI 3.2-4.2, p<0.01). After adjusting for age, race/ethnicity, and diabetes, when compared to normotensive women, women with gestational HTN, chronic HTN, preeclampsia without severe features (SF), and preeclampsia with SF all were more likely to experience SMM (Table). The association between any HTN disorder and SMM is modified by maternal race/ethnicity, with Hispanic women with a HTN disorder having the highest overall odds of experiencing SMM (Figure). In Washington State, HTN disorders of pregnancy are associated with SMM in a dose-dependent fashion. The effect of HTN disorders on SMM is increased among Black and Hispanic women compared to other races and ethnicities. Recognition and management of HTN, especially in minority populations, may help to decrease the rates of SMM and address racial disparities in maternal reproductive health outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)
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