Cost effectiveness of colonoscopy, based on the appropriateness of an indication

Determination of the appropriateness of an indication for colonoscopy has been advanced as a means to help rationalize the use of endoscopic resources. However, the efficacy and cost effectiveness of the current guidelines used to select patients for colonoscopy are largely unknown. The goal of this study was to assess the clinical and economic impact of American Society for Gastrointestinal Endoscopy and the European Panel on the appropriateness of Gastrointestinal Endoscopy appropriateness guidelines in selecting patients who are referred for colonoscopy, in relation to colorectal cancer (CRC) detection.

A decision-analysis model was constructed to compare colonoscopy strategies for "appropriate" indications with those for which colonoscopy is deemed "inappropriate" or "generally not indicated." A 50% cancer upstaging was modeled to simulate cancer progression for patients not referred for colonoscopy. CRC prevalence was estimated using a pooled data analysis based on a systematic review of the literature. Costs of colonoscopy and cancer care were estimated from Medicare reimbursement data. The number of colonoscopies needed to detect one case of cancer and to prevent one cancer-related death and incremental cost-effectiveness ratios (ICER), according to appropriateness categories, were computed in a simulated population of patients that were 60 years of age and referred for colonoscopy.

The numbers of appropriate and inappropriate colonoscopies that needed to be performed to detect one patient with cancer were 18 and 93, respectively. Similarly, 115 and 617 colonoscopies would be needed, respectively, to prevent one CRC-related death. The ICER for appropriate and inappropriate colonoscopies, compared with a policy of not referring patients to colonoscopy, was $6154 and $31,807 per life-year gained, respectively. In a sensitivity analysis, only a reduction from the baseline value of 1.1% to 0.2% was associated with an ICER for inappropriate colonoscopy higher than $150,000.

Current guidelines regarding the appropriateness of colonoscopy are relatively inefficient in excluding a clinically meaningful CRC risk for patients in whom colonoscopy is generally not indicated, raising serious concerns about their applicability to clinical practice.