CRP and myalgic encephalomeyelitis/chronic fatigue syndrome: The multivariate analysis showed that a CRP levels ≥64 mg/L (OR 1.92 [1.35-2.75], p < 0.001) and a CFS equal to or superior to 7 (OR 1.59 [1.07-2.36], p = 0.022) were associated with prolonged LOS.<h4>Discussion</h4>Frailty and inflammation independently predict longer stays.