Impaired metabolic health rather than obesity is associated with coronavirus disease 2019 severity in the Korean population

OBJECTIVE: This study aimed to determine the relative and independent contributions of impaired metabolic health and obesity to coronavirus disease 2019 (COVID-19) outcomes. METHODS: We analyzed 4,069 COVID-19 patients between January and June 2020 in South Korea, classified into four groups according to metabolic health status and body mass index (BMI): metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). The primary outcome was a composite of intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), extracorporeal membrane oxygenation (ECMO), and death. Multivariable Cox proportional hazard regression models were used to estimate the hazard ratio (HR) for the outcome. RESULTS: The incidence rate (per 100 person-months) of severe COVID-19 outcomes was the lowest in the MHNW group (0.90), followed by the MHO (1.64), MUNW (3.37), and MUO (3.37) groups. Compared with MHNW, a significantly increased risk of severe COVID-19 was observed in MUNW (HR, 1.41;95% CI, 1.01-1.98) and MUO (HR, 1.77;95% CI, 1.39-2.44) but not in MHO (HR, 1.48;95% CI, 0.98-2.23). The risk of ICU admission or IMV/ECMO was increased only in MUO;however, the risk of death was significantly higher in MUNW and MUO. The risk of severe COVID-19 increased insignificantly by 2% per 1 kg/m2 BMI increase but significantly by 13% per 1 metabolically unhealthy component increase, even after mutually adjusting for BMI and metabolic health status. CONCLUSION: Metabolic health is more important to COVID-19 outcomes than obesity.