Racial disparities in the mortality and health-care resource utilization of heart failure patients with chronic obstructive pulmonary disease

Abstract

Increased mortality rates in chronic obstructive pulmonary disease (COPD) patients with heart failure (HF) are believed to be driven by various factors, including disparities in access to healthcare services and shifting dynamics of the population characteristics. In this study, we examined the racial and ethnic disparities in the clinical outcomes of HF in COPD patients in the United States, analyzing data from the Nationwide Inpatient Sample database. The database was searched retrospectively from 2016 to 2022 to identify COPD and HF patients by International Classification of Diseases-10 codes. A total of 2445545 individuals were included of which 76% were Whites, 16% were Blacks, 5% Hispanics and 3% others. Whites were significantly older than other populations (P < 0.001), and a significantly higher proportion of Blacks were females compared to other racial groups. Regarding clinical outcomes, Black COPD patients with HF had the lowest mortality rates while it was similar between Whites and Hispanics (P < 0.001). Compared to Whites, the adjusted odds ratio was significantly lower for Blacks, 0.797 [95% confidence interval (CI): 0.783-0.812; P < 0.001] and Hispanics, 0.956 (95%CI: 0.932-0.981; P = 0.001). Other racial groups had significantly higher mortality compared to Whites, with an adjusted odds ratio of 1.131 (95%CI: 1.099-1.164; P < 0.001). Individuals from other racial groups had significantly longer hospital stay, and hospitalization cost adjusted for inflation. Cardiac arrest was the strongest predictor (P < 0.001) for in-hospital mortality in all racial groups.

Key Words: Atrial fibrillation; Chronic obstructive pulmonary diseases; Mortality; Epidemiology; Outcomes

Core Tip: This study analyzed data from the Nationwide Inpatient Sample database to assess the racial disparities in the clinical outcomes of heart failure in chronic obstructive pulmonary disease patients in the United States from 2016 to 2022. The study underscored persistent racial disparities in clinical management and outcomes of chronic obstructive pulmonary disease patients with heart failure, highlighting areas for targeted interventions to promote equitable healthcare delivery.

TO THE EDITOR

Chronic obstructive pulmonary disease (COPD) is characterized by the progressive chronic obstruction of the airways, mainly associated with tobacco smoking[1]. While COPD is a preventable and treatable disorder, advancements in the medical field have failed to reduce its morbidity and mortality[2]. The estimated global prevalence of COPD was 10.6% in 2020, and was projected to increase by 23.3% or 592 million cases by 2050[3]. Individuals diagnosed with COPD often succumb to other comorbid conditions, which worsen quality of life, treatment outcomes, and mortality rates[4]. Notably, higher incidence and prevalence of cardiovascular disorders are reported in COPD patients, with the most common cardiovascular disorders being heart failure (HF), ischemic heart disease, and arrhythmias[5]. Up to half of the COPD patients are found to have higher serum levels of natriuretic peptide, a diagnostic marker of cardiac dysfunction in HF[6].

Increased mortality rates in COPD patients with HF are believed to be driven by various factors, including disparities in access to healthcare services and shifting dynamics of the population characteristics. The mortality trends may also differ across different racial groups, highlighting disparities in healthcare access for marginalized populations[7]. In this study, we examined the racial and ethnic disparities in the clinical outcomes of HF in COPD patients in the United States, analyzing data from the Nationwide Inpatient Sample database. The study was approved by the institutional review board and conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. The database was searched retrospectively from 2016 to 2022 to identify COPD patients [International Classification of Diseases-10 (ICD-10) codes in Supplementary Table 1], followed by HF (ICD-10 codes). Patients without HF and those with missing data were excluded from the analysis (Supplementary Figure 1).

A national estimate of the inpatient burden of COPD and HF was established using weighted hospital discharge data. The race/ethnicity was categorized into four groups namely White, Black, Hispanic and others. Baseline social and demographic characteristics, as well as institutional variables, were reported using frequencies, percentages, means, and SD. A multivariate regression analysis, which reported adjusted odds ratios (aORs) with 95% confidence intervals (95%CI), examined racial/ethnic disparities in in-hospital mortality and resource use. The analysis adjusted for several variables, including age, race, the Charlson Comorbidity Index, hospital factors (such as emergency department admissions, weekend admissions, elective admissions, hospital region, urban or rural location, teaching status, ownership, and bed size), as well as socio-economic factors (median income per ZIP code quartile and insurance status).

A trend analysis was conducted for the outcomes of in-hospital mortality, length of stay and inflation adjusted hospital costs, stratified by race/ethnicity, utilizing the Cochran-Armitage and Jonckheere-Terpstra tests. Trends were evaluated using weighted data integrating discharge weights and hospital strata according to the Healthcare Cost and Utilization Project dataset specifications to ensure national representation. Cost-to-charge ratios and inflation adjusted total charges in accordance with the United States Department of Labor inflation index for Medical Care Consumer Price Index to adjust for inflation in 2022 were applied for cost-based analysis.

A total of 2445545 individuals were included of which 76% were Whites, 16% were Blacks, 5% Hispanics and 3% others (Supplementary Table 2). Whites were significantly older than other populations (P < 0.001), and a significantly higher proportion of Blacks were females compared to other racial groups (P < 0.001). Concerning hospital admissions, elective admissions were more common in Whites (P < 0.001), whereas emergency department admissions were significantly higher in Blacks and Hispanics compared to other racial groups (P < 0.001).

Regarding comorbidities, a significantly greater proportion of White patients had prior myocardial infarction (P < 0.001), prior percutaneous coronary intervention (P < 0.001), and prior coronary artery bypass grafting (P < 0.001), however, prevalence of prior cerebrovascular accident was highest in Blacks (P < 0.001). In-hospital percutaneous coronary intervention and coronary artery bypass grafting were common in Whites compared to Black and Hispanic patients, with a lower prevalence of in-hospital cardiac arrest, in-hospital transfusions, acute ventricular tachycardia, and invasive mechanical ventilation (Supplementary Table 3).

Regarding clinical outcomes, Black COPD patients with HF had the lowest mortality rates while it was similar between Whites and Hispanics (P < 0.001). Individuals from other racial groups had significantly longer hospital length of stay (8.67 days) followed by Hispanics (7.78 days), Blacks (7.72 days) and Whites (6.46 days). Individuals from other racial groups also demonstrated highest total cost adjusted for inflation (P < 0.001). While the prevalence of routine discharge was highest among Black patients (P < 0.001), White patients had the highest prevalence of discharge to skilled nursing facilities (P < 0.001). The annual trends in hospital admissions remained stable throughout the study period for all the racial groups, with a slight decline during 2020-2021, suggesting decreased utilization of healthcare services during the coronavirus disease 2019 pandemic. Moreover, there was a slight rebound in hospital admissions across all racial groups, suggesting a return to normal healthcare utilization during the post-coronavirus disease recovery period in 2022 (Supplementary Table 2).

The age-adjusted mortality rate (AAMR) trends stratified by race during 2016-2022 demonstrated an increase in the mortality rate across all racial groups, with a notable spike during 2019-2020 (Supplementary Figure 2A). Individuals from other racial groups had the highest AAMR, peaking in the year 2021, whereas Black individuals consistently had the lowest AAMR but experienced the highest percentage increase in mortality with an annual percentage change of 7.27. The trend analysis for unadjusted in-hospital mortality rates suggested the highest and lowest mortality rates for “other” racial groups and Blacks throughout the study period, respectively (Supplementary Figure 2B). The Cochran-Armitage test for trend indicated statistically significant trends in mortality rates for all ethnic groups (P < 0.001).

Trend analysis of the mean length of hospital stay stratified by race from 2016 to 2022 indicated an overall increase in the length of hospital stay for White, Black, and other racial groups (Supplementary Figure 2C). All groups but Hispanic showed an increase in the mean length of stay during 2021-2022. The Jonckheere-Terpstra test indicated a statistically significant increase in the mean length of hospital stay for White (P < 0.001), Black (P < 0.001), and other racial groups (P = 0.021). The trend analysis for inflation-adjusted mean hospital cost stratified by age during 2016-2022 indicated an upward trend in hospital costs for all racial groups (Supplementary Figure 2D). Hispanics consistently had higher hospital costs throughout the study period compared to Whites and Blacks. The Jonckheere-Terpstra test indicated statistically significant increasing trends in the inflation-adjusted mean hospital cost for all racial groups (P < 0.001).

The multivariate regression analysis of racial disparities for resource utilization and in-hospital mortality in COPD patients with HF is demonstrated in Supplementary Table 4. Compared to Whites, the aOR was significantly lower for Blacks, 0.797 (95%CI: 0.783-0.812; P < 0.001) and Hispanics, 0.956 (95%CI: 0.932-0.981; P = 0.001). Other racial groups had significantly higher mortality compared to Whites, with an aOR of 1.131 (95%CI: 1.099-1.164; P < 0.001). Compared to Whites, the length of stay was significantly longer in Blacks (P < 0.001), Hispanics (P = 0.001), and other racial groups (P < 0.001). All racial groups had significantly lower odds of being discharged to skilled nursing facilities compared to Whites (P < 0.001). Black COPD patients with HF had significantly lower hospital costs compared to Whites (P < 0.001), whereas Hispanic patients and those from other racial groups had significantly higher hospital costs (P < 0.001). Cardiac arrest was the strongest predictor (P < 0.001) for in-hospital mortality in White, Hispanic, Black, and other racial groups (Supplementary Figure 3).

In summary, this study analyzed data from the Nationwide Inpatient Sample database to assess the racial disparities in the clinical outcomes of HF in COPD patients in the United States from 2016 to 2022. Based on the study findings, Black patients exhibited the lowest unadjusted and AAMRs, despite experiencing the highest percentage increase in mortality over the study period. In contrast, individuals from other racial groups consistently had the highest mortality rates, longer lengths of hospital stay, and the highest total hospital charges and costs. Multivariate analysis confirmed that Black patients had lower odds of mortality and lower hospital costs compared to White patients. This study is subject to several limitations. As the analysis relied on administrative databases using ICD-10 codes, the possibility of coding errors and misclassification bias cannot be excluded. Additionally, the retrospective design restricts causal inference and is vulnerable to residual confounding despite statistical adjustments. This study underscored persistent racial disparities in clinical management and outcomes of COPD patients with HF, highlighting areas for targeted interventions to promote equitable healthcare delivery.