Diagnostic strategies in patients with lower abdominal complaints in primary care

Background Lower gastro-intestinal tract complaints are frequently presented in primary care. About 7% of these patients has organic bowel disease (OBD), such as inflammatory bowel disease (or colorectal cancer. Most have functional disease, such as the irritable bowel syndrome (IBS). Adequate discrimination is important, as both unnecessary endoscopies as well as delayed detection of OBD is burdening and costly. Presently up to 20% of patients with persisting lower gastrointestinal complaints is referred for endoscopy, but only in one-third OBD is found. The diagnostic process in primary care needs improvement. Symptoms and blood tests alone cannot identify OBD accurately, but new point-of-care fecal biomarker tests for inflammation are promising. Methods The CEDAR study aims to identify the most cost-effective diagnostic strategy to estimate the absence or presence of OBD in patients with lower intestinal complaints, combining history, physical examination, blood tests, Rome III criteria for IBS and the point-of-care (POC) fecal biomarker tests calprotectin and an immunochemical fecal occult blood test (iFOBT). Results and Conclusion We demonstrated that stricter adherence to the Rome III criteria in primary care will not lead to a substantial reduction of referrals for endoscopy, but a diagnostic model combining symptoms, signs and the iFOBT and calprotectin POC tests might prevent 30% of current referrals for endoscopy. Future studies should evaluate if both POC tests should be incorporated, or if a model with only the iFOBT POC test has acceptable diagnostic accuracy as well. In contrast to earlier reports we found that the iFOBT POC test has diagnostic value in patients presenting with rectal bleeding. This might be explained by the fact that iFOBT also detects microscopic bleeding. Before our diagnostic model for OBD can be safely used by general practitioners to exclude OBD, it deserves further external validation to check if the model performs well in new patients. After external validation, a diagnostic impact or implementation study is needed to determine whether using the diagnostic model in daily practice actually improves physician’s diagnostic decision-making and cost-effectiveness of the diagnostic work-up.