P115 Arthropathies associated to inflammatory bowel disease (IBD): A retrospective survey

Abstract

Background: In adults, Faecal Calprotectin (FC) ELISA has a sensitivity and specificity of >93% for detecting IBD (1). However, small case series have shown that other factors (eg NSAIDs, cirrhosis, obesity etc) may lead to false +ve results. It is also unclear if immuno-suppressants, taken for non-GI indications can give false ve FC results. Aim: to determine the size and effect of possible factors which might contribute to borderline FC values to cause false +ve or ve results. Methods: Study population: any patient with a FC result held in the pathology database from May 2005 09 (n = 5943). Patient data were cross referenced to electronic records, radiology (PACS), endoscopy & pathology data sets (SnoMed CT). Exclusions: previous diagnosis of IBD or CRC, or aged 50mg/g and <150mg/g were included. Multivariate analysis (generalised linear model) was performed sequentially using SPSS with age, gender, BMI, ethnicity, medication, family history of IBD, smoking/alcohol consumption, liver disease. Histological severity of colonic inflammation was only included in the final model. Results: From 5943 patients, 569 (10%) were between 50 150 and met the inclusion criteria. 62% were female, mean age 51 yr, range 16 91 yr). Diarrhoea (50%) was the most common indication for testing. In the preliminary model FC values increased with age (B = 0.15, p < 0.04) and with a positive trend for liver disease (B = 7.7, p = 0.06); however neither variable remained significant in the final model, which was overwhelmingly dominated by the effect of mucosal inflammation (B = 41, p < 0.001). Immunosuppressant use (mainly for Rharthritis/SLE) was associated with lower FC values (p = 0.027). There was no effect from any of the other variables at any stage in either model.