P226. Non-invasive monitoring of inflammatory bowel disease: Need for better tools?
N. Azzopardi1, P. Ellul1, V. Fenech1
1Mater Dei Hopsital, Gastroenterology Department, Msida, Malta
Background: In inflammatory bowel disease (IBD), biomarkers are used for non-invasive monitoring of disease activity. The commonly used biomarkers are the acute-phase proteins C‑reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR). Ulcerative colitis (UC) is believed to have only a modest to absent CRP response despite active inflammation and the reason for this is unknown. Iron deficiency anaemia (IDA) is also often a marker of longstanding active disease in IBD.
In this study we have analysed the sensitivity and specificity of CRP, ESR and IDA in Crohn's disease (CD) and UC.
Methods: CRP, ESR, Haemoglobin level and Mean Corpuscular Volume taken within 14 days of a colonoscopic examination were analysed. The values were then compared with the histopathological findings from colonic and terminal ileal biopsies.
Results: Colonic biopsies from 95 colonoscopies done in 71 different patients with known UC were analysed (PPV: Positive Predictive Value, NPV: Negative Predictive Value).
| Marker | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|
| CRP | 44.6% | 94.1% | 92.6% | 50.7% |
| ESR | 64.7% | 89.3% | 91.7% | 58.1% |
| IDA | 24.6% | 100% | 100% | 39.5% |
| CRP & ESR | 75.9% | 90% | 93.2% | 67.5% |
Colonic and terminal ileal biopsies from 98 colonoscopies in 62 different patients with known CD were analysed.
| Marker | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|
| CRP | 54.5% | 71.0% | 80.0% | 42.3% |
| ESR | 55.4% | 89.7% | 91.2% | 50.9% |
| IDA | 44.1% | 87.5% | 93.8% | 42.4% |
| ESR & CRP | 70.9% | 70.0% | 83.0% | 53.8% |
Conclusions: UC has a similar CRP response to CD in active inflammation. The commonly used biomarkers have poor sensitivities in demonstrating active mucosal disease. IDA has little value when used as a marker of disease activity on its own but may be used as an adjunct to ESR and CRP or other biomarkers. Faecal biomarkers like calprotectin and lactoferrin [2] and novel antibodies may help to increase the sensitivity and specificity in the non-invasive monitoring of IBD.
1. Vermeire S, Van Assche G, Rutgeerts P (2004), C‑reactive protein as a marker for inflammatory bowel disease. Inflamm Bowel Dis, 661–5, 10(5).
2. Lewis JD (2011), The utility of biomarkers in the diagnosis and therapy of inflammatory bowel disease. Gastroenterology, 1817–1826, 140.