Divergent temporal trajectories of adiponectin and leptin in critically ill patients with COVID-19-associated acute respiratory distress syndrome

Adipokines play an important role in immunometabolic regulation and systemic inflammation, processes profoundly disturbed in COVID-19. Leptin and adiponectin have attracted particular interest because of their opposing biological effects. However, most studies have relied on single time-point measurements, and data on serial adipokine dynamics in critically ill patients with COVID-19-associated acute respiratory distress syndrome (ARDS) remain limited. This study aimed to evaluate circulating leptin and adiponectin concentrations and their temporal changes during the first week of intensive care unit (ICU) treatment. This single-center prospective observational study included 75 adults with COVID-19-associated ARDS admitted to the medical ICU (MICU). Serum leptin and adiponectin concentrations were measured on day 1 and day 7 using enzyme-linked immunosorbent assays. Clinical data, including respiratory support, vasopressor use, comorbidities, and 28-day survival, were prospectively collected. The overall 28-day mortality was 38.7%. Leptin concentrations did not significantly change between day 1 and day 7 in any subgroup. In contrast, adiponectin demonstrated significant temporal changes. Among non-survivors, adiponectin levels decreased markedly during the first week of MICU treatment (p<0.001), whereas no significant change was observed in survivors. Similar declines were observed in patients requiring invasive mechanical ventilation and vasopressor therapy, while patients managed without these interventions showed increasing adiponectin concentrations. The leptin-to-adiponectin ratio showed a trend toward higher values in non-survivors but did not reach statistical significance. In COVID-19-associated ARDS patients, adiponectin demonstrated dynamic changes associated with clinical deterioration, whereas leptin remained relatively stable. These findings suggest that serial adiponectin measurements may have potential for monitoring short-term disease progression in critically ill patients and warrant confirmation in larger prospective studies.