The independent risk factors for cardiac injury in COVID-19 patients with DM were CD3+CD4+ T cells counts ≤ 288 cells/μl (adjusted Odds ratio (OR), 2.501; 95% confidence interval (CI) 1.282–4.877; p = 0.007) and IL-6 > 25.68mpg/ml (adjusted OR, 4.345; 95% CI 2.192–10.374; p < 0.001) (all Pinteraction < 0.05). The gene discussed is CD4; the disease is COVID-19.