Causal mediation analysis indicated that the association between IGFBP7 and ARDS 28-day mortality was mediated by platelet count (OR 1.03, 95% CI 1.02–1.04, p = 0.01), which was consistent with platelet involvement in ARDS-associated inflammation and disseminated intravascular coagulation. The gene discussed is IGFBP7; the disease is acute respiratory distress syndrome.