Metabolic syndrome and the risk of COVID-19 infection: A nationwide population-based case-control study

Metabolic syndrome (MetS) is a chronic, low-grade inflammatory disease. This study aimed to investigate the impact of MetS on the risk and severity of COVID-19. We investigated a nationwide cohort with COVID-19 including all patients who underwent the test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Korea. The COVID-19 group included 4070 patients with positive SARS-CoV-2 test results, and the age- and sex-matched control group included 27,618 subjects with negative SARS-CoV-2 test results. The endpoints were SARS-CoV-2 positivity and the severity of COVID-19. The prevalence of MetS was 24.7% and 24.5% in the COVID-19 and control groups, respectively. The presence of MetS was not associated with the risk of developing COVID-19. Among the components of MetS, central obesity was associated with a higher risk of COVID-19 infection (adjusted odds ratio [aOR], 1.17; 95% confidence interval [CI], 1.06–1.28, P = 0.001). The presence of MetS was significantly associated with severe COVID-19 (aOR, 1.25; 95% CI, 0.78–2.00, P = 0.352). Among the individual components of MetS, prediabetes/diabetes mellitus was associated with a higher risk of severe COVID-19 (aOR, 1.61; 95% CI, 1.21–2.13, P = 0.001). The risk of severe COVID-19 linearly increased according to the number of metabolic components (P for trend = 0.005). In this nationwide cohort study, the individuals with MetS had a significant increase in the risk of severe COVID-19 infection. These patients, particularly those with central obesity and insulin resistance, deserve special attention amid the COVID-19 pandemic. •In a nationwide cohort, central obesity was associated with COVID-19 infection.•MetS was significantly associated with severe COVID-19.•Prediabetes/diabetes mellitus was associated with a higher risk of severe COVID-19.•The risk of severe COVID-19 increased with the number of metabolic components.