Association between COVID-19 severity and relatively high serum adiponectin levels at the time of admission

At the beginning of 2020, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to epidemics worldwide. Obesity and visceral fat accumulation have been reported to be independent risk factors for severe COVID-19. Several reports have focused on the levels of adipocytokines/adipokines, including adiponectin (APN), which is exclusively secreted from adipocytes, although the importance of these factors in acute disease conditions remains unclear. Therefore, we investigated the relationship between serum adiponectin levels and COVID-19 severity. Patients with COVID-19 who were admitted to Sumitomo Hospital (Osaka, Japan) from May through October 2021 were included. A total of 107 patients were enrolled in this study. We obtained the anthropometric and clinical laboratory data of the patients at the time of admission and examined the associations between various parameters and COVID-19 severity. The mean period from onset to admission was 6.5 ± 2.8 days. We divided the patients into "non-severe" (mild, moderate-I and moderate-II) (n = 80) and "severe" (n = 27) groups. The "severe" patients were significantly older than "non-severe" patients. Additionally, no significant differences were observed in BMI, sex, or the period from onset to admission. The serum adiponectin levels of "severe" patients at the time of admission were significantly greater than those of "non-severe" patients even after adjusting for age, sex, and BMI. These results suggest that the serum APN levels at the time of admission can predict COVID-19 severity. However, further investigations on the changes in APN levels in acute diseases are needed.