Comparison of Fecal Calprotectin and Myeloperoxidase in Predicting Outcomes in Inflammatory Bowel Disease

BACKGROUND: Biomarkers have been proposed as surrogate treatment targets for the management of inflammatory bowel disease (IBD); however, their relationship with IBD-related complications remains unclear. This study investigated the utility of neutrophil biomarkers fecal calprotectin (fCal) and fecal myeloperoxidase (fMPO) in predicting a complicated IBD course. METHODS: Participants with IBD were followed for 24 months to assess for a complicated IBD course (incident corticosteroid use, medication escalation for clinical disease relapse, IBD-related hospitalizations/surgeries). Clinically active IBD was defined as Harvey-Bradshaw index >4 for Crohn's disease (CD) and simple clinical colitis activity index >5 for ulcerative colitis (UC). Area under the receiver-operating-characteristics curves (AUROC) and multivariable logistic regression assessed the performance of baseline symptom indices, fCal, and fMPO in predicting a complicated disease IBD course at 24 months. RESULTS: One hundred and seventy-one participants were included (CD, n = 99; female, n = 90; median disease duration 13 years [interquartile range, 5-22]). Baseline fCal (250 μg/g; AUROC = 0.77; 95% confidence interval [CI], 0.69-0.84) and fMPO (12 μg/g; AUROC = 0.77; 95% CI, 0.70-0.84) predicted a complicated IBD course. Fecal calprotectin (adjusted OR = 7.85; 95% CI, 3.38-18.26) and fMPO (adjusted OR = 4.43; 95% CI, 2.03-9.64) were associated with this end point after adjustment for other baseline variables including clinical disease activity. C-reactive protein (CRP) was inferior to fecal biomarkers and clinical symptoms (pdifference < .05) at predicting a complicated IBD course. A combination of baseline CRP, fCal/fMPO, and clinical symptoms provided the greatest precision at identifying a complicated IBD course. CONCLUSIONS: Fecal biomarkers are independent predictors of IBD-related outcomes and are useful adjuncts to routine clinical care.