TABLE 1.
Summary and evidence level of inflammatory bowel disease biomarkers
| Blood biomarkers | Evidence level |
|---|---|
| Crohn disease | |
| There is a correlation between endoscopic but not histological disease activity and CRP levels in Crohn disease (6) | 3b |
| A decrease in CRP is seen in anti-TNF therapy concomitant with increased response/remission to therapy in children and adults (10–14) | 1b |
| Maintenance therapy with an anti-TNF agent is associated with continued normalization of CRP (12) | 1b |
| Baseline elevation in CRP predicts anti-TNF responsiveness (8,9,17) | 2b |
| Among responders to anti-TNF induction, normalization of CRP at week 14 is associated with maintenance of response (17) | 3b |
| Elevation in CRP >5 mg/L, hemoglobin level ≤145 g/L, and leukocyte count >6×109/L predict relapse in patients on combination therapy in whom anti-TNF therapy is discontinued (25) | 2b |
| Elevation of CRP >20 mg/L and hemoglobin level <120 g/L are predictors of relapse in whom azathioprine is withdrawn (22,24) | 2b |
| Ulcerative colitis | |
| CRP is associated with active disease on endoscopy (7,37) | 2b |
| Elevated CRP, low albumin and low hemoglobin levels are predictive of colectomy in acute severe ulcerative colitis (31–36) | 2b |
| Few randomized controlled trials in ulcerative colitis have biomarkers as end points. Small studies have found that clinical response to therapy correlates with a reduction in CRP level (26,28,29) | 1b |
| Fecal biomarkers | |
|
| |
| Crohn disease | |
| Fcalpro is positively associated with endoscopic activity and Crohn disease activity index (6,43) | 3b |
| Change in level correlates with change in endoscopic activity (47,48) | 3b |
| Elevated fcalpro is associated with a higher one-year risk of relapse in Crohn disease (51,64) | 2b |
| Ulcerative colitis | |
| Fcalpro correlates with endoscopic disease and healing (46,52,53) | 2b |
| In trials of vedolizumab, changes in fcalpro correlate with Mayo score (22) | 1b |
| Normalization of fcalpro predicts clinical response to therapy and sustained remission (51,53,54) | 2a |
| In patients on maintenance infliximab, fcalpro was better than CRP at predicting relapse. | 1b |
CRP C-reactive protein; Fcalpro Fecal calprotectin; TNF Tumour necrosis factor