Objective: To evaluate the associations between the number of chronic conditions and maternal race and ethnicity (race) with the risk of severe maternal morbidity.
Methods: Using the National Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, years 2016-2017, we examined risk of severe maternal morbidity among 1,480,925 delivery hospitalizations among women of different races and with different numbers of comorbid conditions using multivariable logistic regression.
Results: The rate of severe maternal morbidity was 139.7 per 10,000 deliveries. Compared with women with no comorbidities (rate 48.5/10,000), there was increased risk of severe maternal morbidity among women with one comorbidity (rate 238.6; odds ratio [OR] 5.0, 95% CI 4.8-5.2), two comorbidities (rate 379.9; OR 8.1, 95% CI 7.8-8.5), or three or more comorbidities (rate 560; OR 12.1, 95% CI 11.5-12.7). In multivariable regressions, similar associations were noted for women with one (adjusted odds ratio [aOR] 4.4, 95% CI 4.2-4.6), two (aOR 6.6, 95% CI 6.3-6.9), or three or more comorbidities (aOR 9.1, 95% CI 8.7-9.6). Black women had higher rates of comorbid conditions than all other racial and ethnic groups, with 55% (95% CI 54-56%) of Black women having no comorbidities, compared with 67% (95% CI 67-68%) of White women, 68% (95% CI 67-69%) of Hispanic women, and 72% (95% CI 71-73%) of Asian women.
Conclusion: We found a dose-response relationship between number of comorbidities and risk of severe maternal morbidity, with the highest rates of severe maternal morbidity among women with three or more comorbidities. Focusing on the prevention and treatment of chronic conditions among women of childbearing age may have the potential to improve maternal outcomes across races and ethnicities.