Risk of Severe Maternal Morbidity Associated with Maternal Comorbidity Burden and Social Vulnerability

Abstract

Objective We evaluated the associations of the obstetric comorbidity index (OB-CMI) and social vulnerability index (SVI) with severe maternal morbidity (SMM).

Study Design Multicenter retrospective cohort study of all patients who delivered (gestational age > 20 weeks) within a university health system from January 1, 2019, to December 31, 2021. OB-CMI scores were assigned to patients using clinical documentation and diagnosis codes. SVI scores, released by the Centers for Disease Control and Prevention (CDC), were assigned to patients based on census tracts. The primary outcome was SMM, based on the 21 CDC indicators. Mixed-effects logistic regression was used to model the odds of SMM as a function of OB-CMI and SVI while adjusting for maternal race and ethnicity, insurance type, preferred language, and parity.

Results In total, 73,518 deliveries were analyzed. The prevalence of SMM was 4% (n = 2,923). An association between OB-CMI and SMM was observed (p < 0.001), where OB-CMI score categories of 1, 2, 3, and ≥4 were associated with higher odds of SMM compared with an OB-CMI score category of 0. In the adjusted model, there was evidence of an interaction between OB-CMI and maternal race and ethnicity (p = 0.01). After adjusting for potential confounders, including SVI, non-Hispanic Black patients had the highest odds of SMM among patients with an OB-CMI score category of 1 and ≥4 compared with non-Hispanic White patients with an OB-CMI score of 0 (adjusted odds ratio [aOR] = 2.76, 95% confidence interval [CI]: 2.08–3.66 and aOR = 10.07, 95% CI: 8.42–12.03, respectively). The association between SVI and SMM was not significant on adjusted analysis.

Conclusion OB-CMI was significantly associated with SMM, with higher score categories associated with higher odds of SMM. A significant interaction between OB-CMI and maternal race and ethnicity was identified, revealing racial disparities in the odds of SMM within each higher OB-CMI score category. SVI was not associated with SMM after adjusting for confounders.

Key Points

• OB-CMI was significantly associated with SMM.

• Racial disparities were seen within each OB-CMI score group.

• SVI was not associated with SMM on adjusted analysis.

Keywords

obstetrics - comorbidities - comorbidity index - sociodemographic factors - community - screening

Publication History

Received: 06 September 2023

Accepted: 04 December 2023

Accepted Manuscript online:
06 December 2023

Article published online:
22 January 2024

• References

• 1 Kilpatrick SK, Ecker JL. American College of Obstetricians and Gynecologists and the Society for Maternal–Fetal Medicine. Severe maternal morbidity: screening and review. Am J Obstet Gynecol 2016; 215 (03) B17-B22
• 2 Centers for Disease Control and Prevention. Severe maternal morbidity in the United States. Updated February 2, 2021 . Accessed May 11, 2023 at: https://www.cdc.gov/reproductivehealth/maternalinfanthealth/severematernalmorbidity.html
• 3 Bateman BT, Mhyre JM, Hernandez-Diaz S. et al. Development of a comorbidity index for use in obstetric patients. Obstet Gynecol 2013; 122 (05) 957-965
• 4 Easter SR, Bateman BT, Sweeney VH. et al. A comorbidity-based screening tool to predict severe maternal morbidity at the time of delivery. Am J Obstet Gynecol 2019; 221 (03) 271.e1-271.e10
• 5 5. CDC/ATSDR Social Vulnerability Index. Agency for Toxic Substances and Disease Registry. Updated November 16, 2022 . Accessed May 11, 2023 at: https://www.atsdr.cdc.gov/placeandhealth/svi/index.html
• 6 Givens M, Teal EN, Patel V, Manuck TA. Preterm birth among pregnant women living in areas with high social vulnerability. Am J Obstet Gynecol MFM 2021; 3 (05) 100414
• 7 Centers for Disease Control and Prevention. How does CDC identify severe maternal morbidity?. 2019 . Accessed November 11, 2022 at: https://www.cdc.gov/reproductivehealth/maternalinfanthealth/smm/severe-morbidity-ICD.htm
• 8 Sklar A, Sheeder J, Davis AR, Wilson C, Teal SB. Maternal morbidity after preterm premature rupture of membranes at <24 weeks' gestation. Am J Obstet Gynecol 2022; 226 (04) 558.e1-558.e11
• 9 Budden A, Wilkinson L, Buksh MJ, McCowan L. Pregnancy outcome in women presenting with pre-eclampsia at less than 25 weeks gestation. Aust N Z J Obstet Gynaecol 2006; 46 (05) 407-412
• 10 Grobman WA, Bailit JL, Rice MM. et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network. Frequency of and factors associated with severe maternal morbidity. Obstet Gynecol 2014; 123 (04) 804-810
• 11 Grobman WA, Bailit JL, Rice MM. et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network. Racial and ethnic disparities in maternal morbidity and obstetric care. Obstet Gynecol 2015; 125 (06) 1460-1467
• 12 Howland RE, Angley M, Won SH. et al. Determinants of severe maternal morbidity and its racial/ethnic disparities in New York City, 2008–2012. Matern Child Health J 2019; 23 (03) 346-355
• 13 Meeker JR, Canelón SP, Bai R, Levine LD, Boland MR. Individual-level and neighborhood-level risk factors for severe maternal morbidity. Obstet Gynecol 2021; 137 (05) 847-854
• 14 Howell EA. Reducing disparities in severe maternal morbidity. Clin Obstet Gynecol 2018; 61 (02) 387-399
• 15 Creanga AA, Bateman BT, Kuklina EV, Callaghan WM. Racial and ethnic disparities in severe maternal morbidity: a multistate analysis, 2008-2010. Am J Obstet Gynecol 2014; 210 (05) 435.e1-435.e8
• 16 Geller SE, Rosenberg D, Cox SM. et al. The continuum of maternal morbidity and mortality: factors associated with severity. Am J Obstet Gynecol 2004; 191 (03) 939-944
• 17 Greenberg MB, Gandhi M, Davidson C, Carter EB. Society for Maternal-Fetal Medicine;, Publications Committee. Society for Maternal-Fetal Medicine Consult Series #62: Best practices in equitable care delivery-Addressing systemic racism and other social determinants of health as causesl of obstetric disparities. Am J Obstet Gynecol 2022; 227: B44-B59
• 18 Headen IE, Elovitz MA, Battarbee AN, Lo JO, Debbink MP. Racism and perinatal health inequities research: where we have been and where we should go. Am J Obstet Gynecol 2022; 227 (04) 560-570
• 19 Royce CS, Morgan HK, Baecher-Lind L. et al. The time is now: addressing implicit bias in obstetrics and gynecology education. Am J Obstet Gynecol 2023; 228 (04) 369-381