Plasma carnitine is associated with fatigue in chronic hepatitis C but not in irritable bowel syndrome

Objectives Fatigue is an important determinant of altered quality of life in patients affected by chronic hepatitis C (CHC) or the irritable bowel syndrome (IBS). In this study, we aimed at determining the contributory role of plasma levels of leptin and carnitine on fatigue in CHC and IBS. Methods We enrolled 70 patients with CHC, 42 with IBS and 44 healthy subjects. Fatigue was evaluated using the Fatigue Impact Scale questionnaire. Body composition was assessed through impedance analysis. Plasma carnitine and leptin were measured. Results Fatigue scores were significantly more elevated in patients with CHC and IBS than in healthy subjects. Patients with CHC, but not with IBS, had significant lower plasma levels of total and free carnitine adjusted for fat mass compared to healthy subjects. In patients with CHC, and not with IBS, fatigue scores were negatively correlated with plasma levels of carnitine. Levels of free carnitine were significantly and independently associated with the severity of fatigue in patients with CHC (OR=2.019, p=0.02, CI 95% [1.01-1.23]).Conclusions In patients with CHC, the severity of fatigue is associated with low level of carnitine, suggesting that an oral supplementation may be effective to relieve fatigue in CHC. The underlying mechanism of fatigue in IBS does not seem to involve carnitine.