Influenza-Associated Outcomes and Healthcare Utilization by Race and Ethnicity in the USA: a Retrospective Cohort Study Using the National Inpatient Sample Database

Background: The influenza virus continues to be a public health concern every season. We aimed to evaluate influenza-associated outcomes and healthcare utilization by race and ethnicity.

Methods: We conducted a retrospective cohort study using the National Inpatient Sample across 2019 and 2020. Influenza pneumonia was selected as the principal diagnosis. Outcomes included mortality, use of respiratory support ventilation, length of stay, and total hospitalization charge. Regression models were adjusted for age, gender, Charlson Comorbidity Index, hospitals' region, bed size, teaching status, insurance status, and median income.

Results: We identified 73,098 individuals hospitalized with influenza pneumonia; 39,807 and 33,291 were admitted in 2019 and 2020, respectively. The sample included 49,829 (68%) White, 11,356 (15.5%) Black, 7526 (10%) Hispanic, 1860 (2.5%) Asian/Pacific, and 617 (0.84%) Native American patients. In-hospital mortality rates and respiratory support (non-invasive ventilation and invasive mechanical ventilation) in 2019 and 2020 were not significantly different across all the races. In 2019 and 2020, the adjusted odds ratios of in-patient mortality were not significantly different. Asians had higher odds of receiving NIV in 2019 but not in 2020 compared to White patients (adjusted odds ratio (aOR) 1.67, p value 0.04). The adjusted odds ratios for receiving IMV were not significantly different between the races in 2019 and 2020.

Conclusions: This study contributes valuable insight into influenza-associated outcomes and healthcare utilization patterns among diverse racial and ethnic groups. Disparities in healthcare utilization were observed among younger (< 65 years) individuals of Black and Hispanic ethnicity.