Trends in comorbidity, acuity, and maternal risk associated with preeclampsia across obstetric volume settings

OBJECTIVE: The objective of this study was to characterize morbidity, acuity, and maternal risks associated with preeclampsia across hospitals with varying obstetric volumes. METHODS: This retrospective cohort analysis used a large administrative data source, the Perspective database, to characterize the risk for preeclampsia from 2006 to 2015. Hospitals were classified as having either low (≤1000), moderate (1001-2000), or high (≥2000) delivery volume. The primary outcomes included preeclampsia, antihypertensive administration, comorbidity, and related severe maternal morbidity. Severe maternal morbidity was estimated using criteria from the Centers for Disease Control and Prevention. Comorbidity was estimated using an obstetric comorbidity index. Univariable comparisons were made with Chi-squared test. Adjusted log linear regression models were fit to assess factors associated with severe morbidity with risk ratios with 95% confidence intervals as the measures of effect. Population weights were applied to create national estimates. RESULTS: Of 36,985,729 deliveries included, 1,414,484 (3.8%) had a diagnosis of preeclampsia. Of these, 779,511 (2.1%) had mild, 171,109 (0.5%) superimposed, and 463,864 (1.3%) severe preeclampsia. The prevalence of mild, superimposed, and severe preeclampsia each increased over the study period with severe and superimposed preeclampsia as opposed to mild preeclampsia increasing the most proportionately (53.2 and 102.5 versus 10.8%, respectively). The use of antihypertensives used to treat severe range hypertension increased with use of intravenous labetalol increasing 31.5%, 43.2%, and 36.1% at low-, medium-, and high-volume hospitals. Comorbid risk also increased across hospital volume settings as did risk for severe maternal morbidity. CONCLUSIONS: Preeclampsia is increasing across obstetric care settings with preeclamptic patients demonstrating increasing comorbid risk, increased risk for severe morbidity, and more frequent need for treatment of acute hypertension.