Study Finds Comorbidities, Pre-Existing Disease Have Significant Impact On COVID-19 Outcomes

A study of more than 750,000 cases of COVID-19 in Indiana examined the impacts of comorbidities and pre-existing disease on COVID-19 outcomes, finding that chronic obstructive pulmonary disease (COPD), cardiovascular disease (CVD), and type 2 diabetes (T2D) had significant impacts.¹

Additionally, the study found that the Black population in Indiana was more adversely affected by COVID-19 than the White population, which is consistent with earlier research.¹

The Midwest has some of the highest prevalence of comorbidities, including hypertension, COPD, and diabetes. However, this study was one of the first to examine the impacts of these diseases on COVID-19 outcomes in the region.¹

“We analyzed COVID-19–positive patients as well as healthy and nonhealthy patients who did not have COVID as controls for the datasets,” corresponding author Xia Ning, PhD, said in a press release. “The large amount of robust electronic health record data from the COVID-19 Research Data Commons provided a relatively complete picture of COVID throughout Indiana from the critical, initial period of the pandemic before home test kits became available.”¹

Collected data included demographics, diagnoses, laboratory results, medications, inpatient and outpatient encounter information, and mortality for all patients. In total, there were 776,759 COVID-19–positive patients and 1,362,527 COVID-19–negative patients between the ages of 0 and 110 years.²

According to the study, pre-existing presence of 1 or more diseases was linked to an increased risk of admission to an intensive care unit (ICU) as well as greater likelihood of death. For many pre-existing conditions, older age, male sex, or both augmented risk of ICU admission for patients with COVID-19.¹

The investigators also noted that patients with COVID-19 and COPD, CVD, hypertension, and T2D had higher mortality rates compared to all COVID-19 patients. Furthermore, older age was significantly associated with ICU admission in patients with COVID-19 and T2D. These findings bolster earlier researchers’ work, which also found that comorbidities had significant effects for patients with COVID-19.²

“Our work validates findings from smaller and less geographically comprehensive studies and also helps resolve previous conflicting findings,” co-author Titus Schleyer, DMD, PhD, said in the press release. “This is one of the biggest studies looking at how pre-existing disease influences the COVID experience, and it allows us to better predict who is going to get infected by COVID—and potentially similar viruses—and suffer more.”

The study results also showed significant evidence of outcomes disparities between minority populations and White populations. Notably, the Black or African American ICU population proportion was larger than the non-ICU population proportion among COVID-19 patients for all comorbidities. This pattern is the same for all comorbidities except COPD among the controls, although the difference between the proportions was not significant except in a few comorbidities (COPD, CVD, venous thromboembolism, acute renal failure, and acute myocardial infarction).²

Additionally, although the COVID-19 Research Data Commons well represents the overall Indiana population, the investigators noted disproportionate representation on the county level. In some counties, approximately 15% of the population was recorded as infected with COVID-19, whereas other counties had infection rates as low as 4%. The investigators found that counties with higher per capita income tend to be better represented and tend to have lower COPD prevalence.²

The significant difference in COVID-19 populations could be due to 2 causes: firstly, some counties were hit by COVID-19 much harder than others, and secondly, health data were not proportionally collected from all counties. The latter is likely due to health care accessibility disparities or health care networks that are not members of the Indiana Health Information Exchange, limiting the data that could be collected.²

“Our examination of this trove of data from throughout Indiana confirms that COVID-19 health disparities—racial, geographic, and economic—clearly exist,” Schleyer said in the press release. “Black patients were much more likely to be admitted to the ICU with COVID-19 than White patients, indicating that Black patients had more severe cases of the disease than White patients. Disparities were also found between rural and urban areas.”¹

Although the COVID-19 pandemic has largely settled into a seasonal epidemic much like the flu, the investigators said continuing to examine its impacts and disparities is crucial to prepare for future pandemics and outbreaks.¹

“The question of why we are interested in researching COVID, now that it’s almost ‘conquered,’ is an important one,” Schleyer said in the press release. “The answer is simple—the next infection is really just right around the corner. It’s not a question of if a pandemic like COVID will happen, but when. There are many pathogens—bacterial or viral—that could have the same or similar infection rates as COVID.”¹

References

1. Statewide study explores how pre-existing disease has influenced the COVID-19 experience. News release. EurekAlert. June 22, 2023. Accessed June 23, 2023. https://www.eurekalert.org/news-releases/993345
2. Zidan N, Dey V, Allen K, Price J, et al. Understanding comorbidities and health disparities related to COVID-19: a comprehensive study of 776,936 cases and 1,362,545 controls in the state of Indiana, USA. JAMA Open. 2023;6(1). doi:10.1093/jamaopen.ooad002