Association of inflammation with mortality in COVID-19 didn't differ by diabetes status

A single-center, case-control study of patients who were hospitalized with COVID-19 found a link between elevated levels of IL-6, IL-8, and interferon-γ-induced protein 10 and mortality risk, regardless of whether patients had type 2 diabetes.

Although inflammation has been associated with mortality in COVID-19, this risk does not appear to vary according to diabetes status, a recent study found.

Researchers performed a case-control study of patients hospitalized for COVID-19 at an academic medical center to examine whether inflammation was related to COVID-19 mortality, as well as whether this relationship differed by type 2 diabetes status. Patients with type 1 diabetes, history of cardiovascular disease, asthma or chronic obstructive pulmonary disease were excluded. Serum levels of eight cytokines and chemokines, including interferon(IFN)-α2, IFN-γ, IL-1α, IL-1β, IL-6, IL-8/CXCL8, IFN-γ-induced protein 10 (IP10)/CXCL10, and tumor necrosis factor α (TNF-α), were determined in patients who lived (controls) and those who died (cases) using immunoassays. The study results were published Jan. 6 by the Journal of Clinical Endocrinology and Metabolism.

Five hundred thirty-eight patients were included in the study, 205 cases who died and 333 controls who survived. Mean age was 72.8 years among cases and 68.0 years among controls, 64% and 59% were men, and 59% and 51% were Hispanic. Seventy-three percent of cases and controls had serum samples collected in April 2020. Multiple logistic regression models showed a significant association between mortality and higher serum levels of IL-6 (adjusted odds ratio [OR], 1.74; 95% CI, 1.48 to 2.06), IL-8 (adjusted OR, 1.75; 95% CI, 1.41 to 2.19), and IP10 (adjusted OR, 1.36; 95% CI, 1.24 to 1.51). Multiple logistic regression models of the combined population with and without type 2 diabetes found no significant interactions between diabetes status and any inflammatory markers after adjustment for age, disease severity, gender, ethnicity, body mass index, and hypertension status.

The authors noted that their results may not be generalizable to other populations with comorbid diseases or COVID-19 patients treated later in the pandemic, as additional therapies are now available. They concluded that in their study, the inflammatory markers IL-6, IL-8, and IP10 were linked with mortality and that this relationship remained consistent regardless of type 2 diabetes and other risk factors. Given this, they wrote, “immunomodulatory therapeutics such as IL-6 inhibitors have the potential to reduce mortality in populations with and without comorbidities. If future interventional studies should confirm this, it would have direct implications for treatment management of COVID-19 patients.”