Prevalence, trends, and outcomes of chronic hypertension: a nationwide sample of delivery admissions

OBJECTIVE: We sought to define the prevalence, trends, and outcomes of primary and secondary chronic hypertension in a population-based sample of deliveries. STUDY DESIGN: An estimated 56,494,634 deliveries were identified from the 1995 through 2008 Nationwide Inpatient Sample. The association of primary and secondary chronic hypertension with adverse fetal and maternal outcomes was evaluated using regression modeling and adjusted population-attributable fractions were calculated. RESULTS: During the study period, the prevalence of primary and secondary hypertension increased from 0.90% in 1995 through 1996 to 1.52% in 2007 through 2008 (P for trend <.001) and from 0.07% to 0.24% (P for trend <.001), respectively. The population-attributable fraction for chronic hypertension was considerable for many maternal adverse outcomes, including acute renal failure (21%), pulmonary edema (14%), preeclampsia (11%), and in-hospital mortality (10%). CONCLUSION: Primary and secondary chronic hypertension were both strongly associated with adverse pregnancy outcomes and accounted for a substantial fraction of maternal morbidity. Prioritizing research efforts in this area is needed.