['Studies on the costs of health care in patients with inflammatory bowel disease (IBD) are increasingly conducted through the collection of self-reported data. We aimed to assess the concordance between estimated annual costs based on self-reported health care utilization and administrative data in IBD.', "Consecutive patients with Crohn's disease or ulcerative colitis visiting the outpatient clinic were enrolled. Participants were asked to fill out a questionnaire on their IBD-specific health care utilization over the past year. Registered health care utilization over the same time period was extracted from medical records. Health care resources were multiplied by their unit prices to obtain costs. Cost estimates were compared, and correlation, sensitivity, and specificity were calculated.", "In total, 101 patients (70 Crohn's disease, 31 ulcerative colitis) were enrolled. Mean direct health care costs were &OV0556;4758 per year according to self-reported data and &OV0556;4866 according to administrative data (r = 0.97). Hospitalizations and diagnostics were relatively underreported with a sensitivity of 75% and 88%, and a specificity of 100% and 88%, respectively. One of 7 surgical procedures was overreported, and only 1 of 25 patients did not report the use of anti-tumor necrosis factor compounds. Suffering from a flare or having a pouch predicted a decreased recall with an adjusted odds ratio of 3.5 (95% confidence interval, 1.3-9.6) and 10.7 (95% confidence interval, 1.1-107.6), respectively."] Does self-reported Health Care Utilization of Patients with Inflammatory Bowel Disease correlate Perfectly with Medical Records?