The cost-effectiveness of interleukin-1 genetic testing for periodontal disease

Background: A genetic test for a composite interleukin-1 (IL-1) genotype is being marketed to predict risk for progression of periodontal disease. The objective of this study was to determine the clinical scenario required to produce cost-effective results with the use of IL-1 testing to identify high-risk patients. Methods: A disease simulation model was developed using decision-analytic techniques and a 30-year time frame. Results: Using different modeling scenarios, the genetic test produced results ranging from cost savings of $830,140 and 52.8 fewer cases of severe periodontitis to increased costs of $300,430 and 3.6 additional cases of severe periodontitis (per 1,000 patients). Three parameters in the analysis were highly influential: 1) the compliance rate for maintenance therapy in test positive versus non-tested patients; 2) the effectiveness of non-surgical therapy; and 3) the relative risk of disease progression for test positive patients. Conclusion: The model produced a wide range of outcomes reflecting our incomplete understanding of the biology, optimal treatment, and genetic susceptibility of periodontal diseases. However, the model demonstrates that three clinical parameters are highly influential in determining if IL-1 testing can be implemented in a primary care setting in a cost-effective manner.