In multivariate analysis, greater frailty (CFS>3) (OR 11.3, 95% C.I. 2.3–96.7, p<0.05), low albumin (<30g/L) (OR 2.5, 95% C.I. 1.0–6.2, p<0.05), high NLR (≥3) (OR 2.2, 95% C.I. 1.5–4.5, p<0.05) and the 4C score (OR 2.4, 95% C.I. 1.0–5.6, p<0.05) remained independently associated with 30-day mortality. This evidence concerns the gene ALB and myalgic encephalomeyelitis/chronic fatigue syndrome.