Purpose: The introduction of reimbursement for screening colonoscopy in Germany more than one year ago raised concerns that the consequent workload might lead to underuse of diagnostic colonoscopy for symptomatic patients. Available appropriateness criteria for diagnostic colonoscopy have been rarely tested in a realistic outpatient setting. This study was designed to test current appropriateness criteria for diagnostic colonoscopy to better select patients and potentially provide more capacity for screening cases. Secondary goals were yield and quality control in both the diagnostic and screening cases.
Methods: A prospective study was initiated in 39 private-practice offices to collect data on consecutive colonoscopies conducted during a 6-day study period. A detailed questionnaire was developed to define indications and symptoms, and all findings at colonoscopy were recorded. Colonoscopies were further analyzed and stratified into a screening and a diagnostic group. In the diagnostic group, indications were assessed according to the current guidelines for appropriateness (American Society for Gastrointestinal Endoscopy, European Panel for the Appropriateness of Gastrointestinal Endoscopy), and the results were correlated with the percentage of relevant findings (tumors, inflammatory conditions).
Results: During the study period, 1,397 colonoscopies (57 percent screening, 43 percent diagnostic) were analyzed (male/female ratio = 39/61 percent; mean age, 61 years). Fourteen percent and 37 percent, respectively, of the 605 diagnostic colonoscopies were regarded as inappropriate relative to the criteria of the American Society for Gastrointestinal Endoscopy and the European Panel for the Appropriateness of Gastrointestinal Endoscopy. However, the percentage of relevant inflammatory and neoplastic findings (polyps, cancer, inflammatory bowel disease, benign strictures) was only 5 to 10 percent higher in the appropriate group than in the inappropriate group. On the basis of these data, a hypothetical model for selecting appropriate indications was developed: if patients older than aged 50 years with pain, bleeding, and diarrhea, but not constipation, are regarded as having an appropriate indication, such an approach would save 20 percent of colonoscopies in these main indication groups (bleeding, pain, diarrhea, constipation), with a hypothetical miss rate for relevant findings (as defined above) of 5 percent.
Conclusions: Currently used appropriateness criteria for diagnostic colonoscopy increase the yield of relevant findings but lead to a miss rate for relevant findings in the range of 10 to 15 percent. Simple selection criteria based on age and symptoms could be more suitable and should be tested in a larger group of patients.