266 Materials and Methods Study population This cohort study included patients from the database of the IBD center of the University Medical Center Groningen (UMCG). Serum samples from 118 IBD patients, either CD (n = 64) or UC (n = 54) were collected. At the moment serum samples were obtained, all patients had an indication for starting new biological therapy. Indications to initiate biological therapy were primarily based on increased endoscopic disease activity, though few (CD) patients had fistulizing disease as therapy indication. Inclusion criteria for this study were: age ≥ 18 years and an established diagnosis of IBD existing for at least 1 year. Diagnosis was based on clinical, endoscopic and histological criteria. 23 Clinically relevant data were retrieved from the patients’ medical records: age, gender, bodymass index (BMI), smoking status, Montreal classification, maintenance medication (mesalamine, thiopurines, methotrexate, TNF-antagonists), disease duration, previous anti-TNF therapy and surgical history. Clinical disease activity was recorded by scoring the Harvey Bradshaw Index (HBI) for CD and the Simple Clinical Colitis Activity Index (SCCAI) for UC.24, 25 Ethical considerations Serum samples were obtained after patients gave written informed consent (study approved by the Institutional Review Board [IRB] of the UMCG registered as no. 08/338). In addition, serum samples of 20 healthy controls were included for comparison. Serum samples were retrieved from an UMCG biobank containing pre-donation samples of living kidney donors (PSI-UMCG [IRB no. 08/279]). This study has been performed in accordance with the principles of the Declaration of Helsinki (2013). Laboratory measurements Serum samples for measurement of routine diagnostic laboratory parameters, including hemoglobin levels, C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), white blood cell count (WBC) and thrombocyte counts, were obtained simultaneously with the serum samples collected for measurements of inflammatory biomarkers. At the same time-point, fecal calprotectin levels were quantified by enzyme-linked immunosorbent assays (ELISA) (Bühlmann Laboratories AG, Switzerland) in a subgroup of patients (n = 25). Endoscopic disease activity Baseline endoscopy investigation was performed in a subset of 71 IBD patients (CD, n = 36; UC, n = 35) within 3 months prior to serum sample collection (median [IQR] interval: 31 [19;60] days). Endoscopic disease activity was graded based on available endoscopic images and endoscopy reports written by certified gastroenterologists fromour university hospital whowere not involved in the study. Disease activity was scored according to the validated Simplified Endoscopic Score for CD (SES-CD) and Mayo endoscopic subscore for UC.3,4 To calculate the SES-CD, 5 different bowel segments were scored and defined as follows: ileum (excluding the ileocecal valve or ileocolonic anastomosis), ascending colon (including ileocecal valve, cecum and ascending colon until the hepatic flexure), transverse colon (between hepatic and splenic flexures), descending Chapter 8
RkJQdWJsaXNoZXIy MjY0ODMw