Study Details Trends and Outcomes of Stroke in Hypertensive Disorders of Pregnancy

A new analysis using data from the United States National Inpatient Sample is providing an updated overview of trends, predictors, and outcomes associated with stroke in women with hypertensive disorders of pregnancy.

Results of the study indicate the prevalence of stroke events in these women has declined over time and suggest conditions such as sickle cell disease and dyslipidemia were linked to increased risk of stroke.

“Our analysis of over 4.2 million hypertensive disorders of pregnancy delivery hospitalizations show that while the prevalence of HDP has increased over time, incident stroke rates have declined but remain important predictors of delivery complications, including mortality and cesarean section. Women with stroke are increasingly multimorbid with distinctive risk profiles for ischemic and hemorrhagic complications,” wrote investigators.

While many previous studies have described the risk of stroke associated with hypertensive disorders of pregnancy, much of this data fails to provide clinicians with current information related to trends, predictors, and outcomes of stroke in these women. With this in mind, a team from the UK and Emory University designed the current study to fill this apparent gap in knowledge.

Using a timeframe lasting from 2004-2011, investigators sought to identify all women with a delivery hospitalization within the National Inpatient Sample. From their search, investigators identified a cohort of 4,240,284 patients with hypertensive disorders of pregnancy with necessary covariate information. For the purpose of the study, patients were required to have information available related to year of admission, age, weekday/weekend admission, race/ethnicity, median zip code income quartile, hospital region, smoking, congenital heart disease, dyslipidemia, ischemic heart disease, peripartum cardiomyopathy, arrhythmias, previous stroke, sickle cell disease, obstetric factors associated with gestational hypertension or coagulopathy, and selected Agency for Healthcare Research and Quality Elixhauser comorbidity measures.

Among the 4.2 million patients with a hypertensive disorder of pregnancy at time of delivery, 3391 experienced a stroke between 2004 and 2014. The analysis indicated prevalence of hypertensive disorders of pregnancy episodes at delivery increased from 8.4% in 2004 to 10.9% of total hospitalizations in 2014. Conversely, the proportion of stroke diagnoses among these patients decreased from 10 per 10,000 hypertensive disorders of pregnancy delivery hospitalization in 2004 to 6 per 10,000 in 2008 and remained stable through 2014. Over the 11-year study period, investigators found little change in the median age and the composition of race groups in both the overall population and those who suffered a stroke.

Results of the multivariable-adjusted analysis revealed preexisting neurological disorders (aOR, 17.35; 95% CI, 13.42-22.43), peripheral vascular disease (aOR, 10.03; 95% CI, 3.98-25.25), congenital heart disease (aOR, 7.38; 95% CI, 3.85-14.16), fluid and electrolyte disorder (aOR, 5.90; 95% CI, 4.65-7.49), and previous stroke (aOR, 4.77; 95% CI, 2.09-10.87) were associated with increased risk of stroke in the study population. Additional analysis suggested most risk factors associated with stroke were the same for ischemic and hemorrhagic strokes, but also noted congenital heart disease, peripheral vascular disease, dyslipidemia, and sickle cell disease were more strongly associated with ischemic stroke.

Investigators also examined associations of stroke with delivery complications. These analyses indicated stroke was associated with a 100-fold increase in the risk of maternal mortality (OR, 99.78; 95% CI, 59.15-168.31). Investigators pointed out this risk was even more apparent in the case of hemorrhagic stroke (OR, 260.80; 95% CI, 138.10-492.51) compared to ischemic stroke (OR, 30.34; 95% CI, 12.32-74.73). Furthermore, stroke was also associated with an increase in odds of cesarean section (OR, 1.58; 95% CI, 1.33-1.86) and postpartum hemorrhage (OR, 1.91; 95% CI, 1.54-2.37). Of note, no change in the association between stroke and delivery complications was observed during the study period.

Investigators also observed increased length of hospital stay (median,6 vs 3 days), higher hospital charges (median, $14,655 vs $4762), and a higher proportion of nonroutine discharge locations (38% vs 4%) among women with stroke.

This study, “Temporal Trends in Pregnancy‐Associated Stroke and Its Outcomes Among Women With Hypertensive Disorders of Pregnancy,” was published in the Journal of the American Heart Association.