Race alone is not a biological risk factor of all-cause mortality in patients with COPD; other environmental and community factors may contribute.
People with COPD who live in urban areas and in disadvantaged neighborhoods have significantly elevated all-cause mortality, suggesting that social determinants of health impact COPD outcomes, Camille Robichaux, MD, and colleagues report in the International Journal of Chronic Obstructive Pulmonary Disease.
“Prior studies showed that rural areas in the US had higher rates of COPD-related mortality compared [with] urban areas; however, we found that, in a population of patients with COPD, individuals living in more urban areas and those in more disadvantaged neighborhoods were more likely to die from any cause,” Dr. Robichaux says. “This might point to environmental factors, like air pollution.”
She adds, “We also found that Black people with COPD had higher mortality, but after we adjusted for covariates, including where they lived and some comorbidities that can be exacerbated by the environment, they had lower all-cause mortality,” she notes. “This adds to the growing body of evidence that race is not a biological risk factor.”
Few Population-Based Studies of Mortality in COPD Exist
COPD is the third leading cause of death worldwide, and community risk factors have been implicated in differences in respiratory disease severity and mortality. Yet the literature contains few population-based studies of mortality in COPD that include both individual characteristics and community risk factors.
To fill that gap, the researchers conducted a retrospective cohort analysis of all patients enrolled in the Veterans Health Administration with a COPD diagnosis from 2016 to 2019. They obtained demographic characteristics, comorbidities, and geocoded residential addresses to determine Area Deprivation Index and rurality classification.
Of the 1.1 million patients with COPD, 33.4% died as of January 2021. Overall, 95.5% of participants were male, 78.3% were White, and 13.2% were Black or African American; 58.8% lived in urban areas, and an estimated 39.5% and 1.6% lived in rural or highly rural areas, respectively.
The researchers used age-adjusted logistic regression to investigate links between sociodemographic and geographic characteristics with all-cause mortality; and they adjusted for potential confounders, including biological (eg, comorbidities, age, sex) and socioeconomic (eg, neighborhood disadvantage, race, and rurality) status.
Race Is Among Several Factors Linked With All-Cause Mortality
In age-adjusted-only models, having more comorbidities, being Black or African American (adjusted OR [aOR], 1.09; 95% CI, 1.08-1.11), and living in a more disadvantaged neighborhood (aOR, 1.30; 95% CI, 1.28-1.32) were linked with higher odds of all-cause mortality (Figure).
Being female (aOR, 0.67; 95% CI, 0.65-0.69), Asian (aOR, 0.64; 95% CI, 0.59-0.70), and living in a rural area were linked with lower odds of all-cause mortality (aOR, 0.92; 95% CI, 0.89-0.95 for very rural).
After adjusting for comorbidities, age, neighborhood disadvantage, race, and urbanicity, the odds of all-cause mortality for Black or African American patients decreased (from aOR 1.09; 95% CI, 1.08–1.11 to aOR 0.98; 95% CI, 0.96-0.99).
“This implies that race alone is not a determinant in all-cause mortality, and that other factors included in our model, such as socioeconomic status, comorbidities and urbanicity, influence the outcome,” the authors wrote. “Future studies should focus on exploring mechanisms by which disparities arise and developing interventions to address these.”
Further Research Planned With Goal to Improve Public Health
Dr. Robichaux and colleagues plan to continue studying why people with COPD living in urban areas and more disadvantaged neighborhoods have higher odds of all-cause mortality. “We plan to study how long-term exposure to air pollutants, including ozone and PM2.5 (fine particulate matter generally ≤2.5 μm in diameter) contribute to mortality,” she says.
“Using individual level data instead of population-level aggregated data will allow us to look more closely at ways to mitigate risks on a public health scale,” Dr. Robichaux explains. “This knowledge will help guide public policy.”