Disparities in Failure to Rescue Rates Drives Racial Differences in Maternal Mortality

Guohua Li, MD, DrPH

New research suggests failure to rescue from severe maternal morbidity is responsible for more than half of the increased risk for maternal mortality seen between Black and White women.

The study found rates of several maternal morbidities, which included events such as preeclampsia and sepsis, were approximately twice as high among Black women compared to White women and the adjusted rate of mortality among these women was 1.79-fold greater among Black women.

"Our study confirms that excess maternal mortality continues to be a serious public health problem and improving the quality of obstetric care, especially for Black and other minority women, could help substantially decrease maternal mortality and reduce racial and ethnic disparities in maternal mortality in the United States,” said Guohua Li, MD, DrPH, senior investigator of the study and professor of Anesthesiology and Epidemiology at Columbia Mailman School of Public Health, in a statement.

With an interest in evaluating trends and disparities related to failure to rescue in women with severe maternal morbidity, Li and colleagues sought to perform a retrospective cohort study using administrative data from the National Inpatient Sample from 1999-2017. Using ICD codes, investigators assessed risk for 21 specific severe maternal morbidities, including 16 maternal conditions and 5 procedures.

Included among these 16 conditions were eclampsia, acute heart failure, sepsis, amniotic fluid embolism, and severe anesthesia complications, among others. The 5 procedures included hysterectomy, need for ventilation, and temporary tracheostomy.

The primary outcome of interest for the study was failure to rescue from severe maternal morbidity. Investigators obtained information related to patient and hospital characteristics from the National Inpatient Sample and planned to use this information in adjusted analyses to assess disparities in different racial and ethnic groups through the failure to rescue rate ratio. For the purpose of analysis, these groups were defined as non-Hispanic Black, Hispanic, non-Hispanic White, other, and missing, with non-Hispanic White serving as the reference cohort.

From 1999-2017, investigators identified 73,934,559 delivery hospitalizations, including 993,864 with severe maternal morbidity (13.4 per 1000; 95% CI, 13.3-13.5). The severe maternal morbidity rates were greater among both non-Hispanic Black (22.4 per 1000; 95% CI, 22.2-22.6) and Hispanic (15.0 per 1000; 95% CI, 14.9-15.1) women compared to White (11.2 per 1000; 5% CI, 11.1-11.3) women. Among the 993,864 women with severe maternal morbidity, 4328 died (4.3 per 1000; 95% CI, 4.2-4.5).

In adjusted analyses, results indicated all groups had greater failure-to-rescue rate ratios than the control group of White women. The greatest failure-to-rescue rate ratio was seen among non-Hispanic Black women (1.79; 95% CI, 1.77-1.81), followed by women with missing race and ethnicity (1.43; 95% CI, 1.42-1.45), women of other race and ethnicity (1.39; 95% CI, 1.37-1.41), and Hispanic women (1.08; 95% CI, 1.06-1.09).

When assessing factors associated with mortality, investigators found women with severe maternal morbidity who died were more likely to be older, have non-private insurance, have a lower household income, and have a higher obstetric comorbidity index. These patients were also more likely to be transferred from another acute care hospital, be admitted during a weekend, have a cesarean birth, or deliver in a large-bed size or urban teaching hospital.

Investigators also pointed out the severe maternal morbidity rate increased significantly in each of the groups examined during the study, but began to decline beginning in 2012. Additionally, further analysis indicated the failure-to-rescue rate decreased significantly throughout the study period.

"Despite the continuing decrease in failure to rescue over the entire study period, racial and ethnic disparities in failure to rescue persisted, underscoring the need to identify factors accounting for these disparities and to identify interventions to avoid potentially preventable deaths in racial and ethnic minority women," said Jean Guglielminotti, MD, PhD, lead investigator of the study and in the Department of Anesthesiology, Columbia Medical Center, in the aforementioned statement.

This study, “Racial and Ethnic Disparities in Death Associated With Severe Maternal Morbidity in the United States,” was published in Obstetrics & Gynecology.