Is a novel diagnostic pathway for cardiology outpatient clinics in Singapore lower cost than existing practice: a cost modelling study

OBJECTIVE: To evaluate the potential for change to costs from a decision to adopt a novel diagnostic pathway for referrals to cardiology outpatients with symptoms of chest pain. DESIGN: Costs modelling study using existing observational data, with a cost year of 2018. SETTING: Specialist Heart Centre in Singapore. PARTICIPANTS: All new referrals (n=10 622) to the outpatient clinics for investigation between January 2017 and December 2017. INTERVENTIONS: Two competing testing regimes are compared in a decision tree model. Current practice includes classification of patients by their risk and the use of treadmill tests, calcium scores, functional testing and CT angiogram. New practice offers a fundamental difference in use of diagnostics for patients, with some offered angiogram directly and for low-risk patients a calcium score is used to refine risk stratification. OUTCOME MEASURES: The expected cost difference between testing alternatives. RESULTS: The expected cost saving from ‘New Practice’ as compared with ‘Current Practice’ is $S764 per patient. There is a 50% probability the savings per patient range between $S764 and $S824 and a 90% probability they are between $S616 and $S912. The expected savings to Singapore national health services are $S26.8 million annually, with a range of $S16.2 to $S41.1 million. CONCLUSIONS: We find some evidence that using a coronary calcium score, which can be performed with a fraction of the time and cost of a CT coronary angiogram, saves costs to health services.