Ethnic disparities in COVID-19 mortality rates among hospitalized patients in California

By Vijay Kumar MalesuReviewed by Lily Ramsey, LLMDec 6 2023

In a recent study published in Scientific Reports, a group of researchers investigated the association between race and outcomes (mortality and intensive care unit (ICU) admission) in Coronavirus Disease-2019 (COVID-19) hospitalizations in California.

Study: Racial difference in mortality among COVID-19 hospitalizations in California. Image Credit: Gorodenkoff/Shutterstock.com

Background 

The United States (US) leads globally in COVID-19 cases and deaths, with over 84 million cases and 1 million fatalities. Racial disparities in COVID-19 morbidity and mortality have been evident since the pandemic's onset.

For example, the death rates are also greater in Midwestern counties that are dominated by Latino deaths among the Spanish-speaking population and disproportionate admission and deaths of blacks in Louisiana.

Therefore, resolving these disparity elements that involve comorbidities, healthcare access, behavior, and societal interaction are major public health challenges. These disparities are crucial for the management of COVID-19’s spread, as well as ensuring that the health sector is fair. Further research is needed to develop targeted interventions addressing these disparities.

About the study 

The present study conducted a retrospective analysis of the California State Inpatient Database (SID) for the year 2020, as developed by the Agency for Healthcare Research and Quality (AHRQ).

The study focused only on hospitalized cases among adult patients aged at least 18 diagnosed with COVID-19. The hospitalizations were separately categorized based on race such as Blacks, Hispanics, Asians, Whites, etc.

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were employed to identify hospitalizations and procedures, particularly using the ICD-10-CM diagnosis code U07.1 for COVID-19.

The study's primary outcome was in-hospital mortality, and the secondary outcome was ICU admission. Comorbidities under consideration included hypertension, diabetes mellitus, hyperlipidemia, obesity, and atrial fibrillation, among others.

Elixhauser's comorbidity index constitutes another indicator that includes all comorbidities. Race was used to distribute and describe the demography and clinical characteristics of COVID-19 hospitalizations.

For statistical analysis, survival analysis was performed using the Kaplan–Meier estimator, comparing COVID-19-related mortality across different racial groups. Cox proportional hazard regression analyses were used to compare mortality across races, adjusting for various covariates.

Binary logistic regression was conducted to examine differences in ICU admission among racial groups, also adjusting for covariates. The interaction of race with factors like age, sex, diabetes, obesity, and hypertension was analyzed. All statistical analyses were conducted using SAS version 9.4, with a significance level set at P < 0.05, and all tests were two-sided.

The study's findings indicated significant racial disparities in COVID-19 hospitalization outcomes in California, with particular emphasis on the differences in mortality and ICU admission rates among different racial groups.

Study results 

In this study of COVID-19 hospitalizations in California, 87,934 cases were analyzed, with the majority being Hispanics (56.5%), followed by Whites (27.3%), Asian Pacific Islanders and Blacks (6.3%), and Native Americans (9.9%).

The age distribution revealed most patients were between 45 and 85 years, with a greater proportion of male hospitalizations across all racial groups. Insurance coverage varied significantly among races, with most Hispanics having Medicaid, while other races primarily had Medicare.

Common comorbidities included chronic renal failure, hypertension, hyperlipidemia, obesity, and chronic pulmonary disease. Notably, the rates of specific comorbidities varied by race.

The overall in-hospital mortality was 11.5%, ICU admission stood at 9.8%, and among ICU admissions, 64.2% resulted in death. Hispanics experienced the highest mortality rates (63.6%) in ICU admissions, followed by Whites (21.1%), Asian Pacific Islander Native Americans (9.5%), and Blacks (5.6%). The highest mortality for those with no ICU admissions during hospitalizations was in Whites at 42.1%, then Hispanics at 40.6%.

Survival analysis stratified by race indicated that Hispanics had the lowest survival rates, followed by Asian Pacific Islander Native Americans, Whites, and Blacks.The Cox proportional regression analysis revealed a higher mortality risk among Hispanics compared to other races, with significant hazard ratios indicating increased risk.

Comorbidities like diabetes mellitus, coagulation disorder, liver disease, obesity, atrial fibrillation, chronic renal failure, congestive heart failure, and metastatic cancer were associated with a greater risk of mortality.

ICU admission rates were highest among Hispanics, followed by Asian Pacific Islander Native Americans, Blacks, and Whites. Logistic regression analysis confirmed that the odds of ICU admission were significantly higher for Hispanics compared to other races.

This pattern did not show significant interactions when analyzed with factors like age, diabetes, obesity, sex, and hypertension.

These findings underscore significant racial disparities in COVID-19 hospitalization outcomes in California, highlighting the critical need for targeted healthcare strategies to address these inequities.

The higher mortality and ICU admission rates among Hispanics point to underlying issues related to healthcare access, comorbidities, and social determinants of health that disproportionately affect this group.

The study's results call for further investigation into the specific factors contributing to these disparities to inform public health interventions and policy decisions aimed at reducing inequity and improving health outcomes for all racial and ethnic groups affected by COVID-19.