Circulating miR-155 Expression in Patients with Coronary Artery Disease and Prior COVID-19: Associations with Disease Severity and Clinical Outcomes

Abstract

Background: Coronary artery disease (CAD) remains a leading cause of morbidity and mortality worldwide. Patients with CAD are at increased risk of adverse outcomes following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. MicroRNA-155 (miR-155), a key regulator of inflammatory pathways, may be associated with cardiovascular complications following COVID-19. Objectives: This study evaluated circulating miR-155 expression in patients with CAD and a history of COVID-19 and investigated its associations with clinical characteristics, disease severity, ICU admission, and mortality. Methods: This single-center observational comparative study was conducted at Bouali Hospital, Qazvin University of Medical Sciences, Iran. Peripheral blood samples were collected between 2020 and 2022 from 56 patients with angiographically confirmed CAD and documented SARS-CoV-2 infection and 28 CAD controls without documented SARS-CoV-2 infection. MicroRNA-155 expression was quantified using quantitative real-time polymerase chain reaction. Associations between miR-155 expression and demographic variables, comorbidities, COVID-19 severity, ICU admission, and mortality were evaluated. Results: MicroRNA-155 expression was significantly elevated in CAD patients with a history of COVID-19 compared with CAD controls (P < 0.0001). Associations reported with high miR-155 expression included male sex (P = 0.02), diabetes mellitus (P = 0.001), hypertension (P = 0.0001), severe COVID-19 (P = 0.0045), ICU admission (P = 0.0004), and mortality (P = 0.0017). The analyses reported unadjusted P values. Adjusted estimates, confidence intervals for clinical subgroup comparisons, and the threshold used to classify miR-155 expression as high or low were not reported. Therefore, these subgroup findings should be interpreted as exploratory and potentially confounded. Conclusions: Elevated circulating miR-155 expression was significantly associated with severe COVID-19 and adverse recorded clinical outcomes among patients with CAD. These findings support a potential association between miR-155 and inflammatory processes in this population. Larger prospective studies are required to determine its prognostic value and clinical utility. These exploratory associations do not demonstrate that miR-155 independently predicts ICU admission or mortality. Independent cohorts, longitudinal sampling, and adjustment for established risk factors are needed before its use as a clinical biomarker can be recommended.