Heritable thrombophilia test utilization and cost savings following guideline-based restrictions: An interrupted time...

Existing guidelines provide indications for appropriate heritable thrombophilia (HT) testing but testing practices often do not conform to these guidelines. The Canadian province of Newfoundland and Labrador (NL) implemented a new 'hard-stop' guideline-based approach to HT testing whereby tests ordered outside specific guidelines were rejected. The objective of this study was to evaluate the effectiveness of this intervention and the associated cost savings.

Using data on number of HT tests ordered and performed in NL between December 1, 2014 and February 28, 2018, we conducted interrupted time series analyses to analyze changes in number of HT tests ordered and performed following the intervention. Cost savings were estimated by comparing cost of tests actually performed after enforcement of guidelines with the cost of counterfactual number of tests that would have been performed without guidelines.

Guideline-based restrictions on HT testing were associated with a 86-98% decline in the number of tests performed (p < 0.05). Contrary to previous softer, educational approaches to restricting HT testing, number of Protein C and Factor V Leiden/Prothrombin G20210A tests ordered also declined post-guideline implementation (p < 0.05). Annual cost savings associated with reductions in tests performed were estimated to be $205,154 for NL from a societal perspective. We estimated that if this model was expanded across Canada, annual cost savings could be as large as $14.2 million from a societal perspective.

A 'hard-stop' guideline-based approach to restricting HT testing is associated with significant reductions in HT testing and meaningful cost savings.