Asymptomatic hyperCKemia During Infliximab Therapy in Patients With Inflammatory Bowel Disease

Background: Both muscle-related complaints and elevated serum creatine kinase (CK) levels have been reported in patients with inflammatory bowel disease (IBD) treated with infliximab (IFX), mainly as case reports. The aim of this study was to investigate the effect of IFX therapy on serum CK levels in a cohort of Greek IBD patients. Methods: Demographic, clinical (including muscle complaints), and laboratory data of consecutive IBD patients undergoing IFX treatment and a matched control group of IBD patients without any use of biological treatment were retrospectively analyzed. In both groups, patients having at least 3 CK measurements, with at least 10 days' interval among them, were included. Results: The IFX-treated IBD patient group included 82 individuals (75.6% Crohn's Disease [CD]; mean age, 44.7 +/- 13.3 years; 60.9% men; median [interquartile range {IQR}] duration of IFX treatment, 27 [12-84] months). Eighty-two patients without treatment with any biological agent formed the control group (62.2% CD; mean age, 50.4 +/- 16.4 years; 59.8% men). Twenty-five IFX-treated patients (30.5%) had elevated mean serum CK levels (> 180 U/L), compared with 9 (11%) in the control group (P = 0.0003). The median CK value in the IFX group (123.5 U/L; IQR, 91-190.75) was significantly higher than that of the control group (81 U/L; IQR, 57-112.75; P < 0.0001). In the logistic regression analysis, the presence of hyperCKemia was independently correlated with the use of IFX (odds ratio, 4.03; IQR, 1.64-9.90; P = 0.002). No patient with hyperCKemia in both groups reported any persistent symptom of myopathy. Conclusions: More than 30% of IBD patients on IFX present asymptomatic persistent and treatment-related hyperCKemia. Further relevant prospective investigation is needed.