Cost-effectiveness of alternative cascade screening strategies for familial hypercholesterolemia with realistic cascade screening acceptance rates and use of novel treatment.

Cascade screening (CS) for familial hypercholesterolemia (FH) has been found to be cost-effective in many published studies. However, most existing studies (i) ignored or overstated first-degree relative (FDR) participation rate (as 60-100 %), (ii) did not consider novel and expensive therapies, e.g. PCSK9 inhibitors (PCSK9i), and (iii) were conducted outside of Asia. This study, conducted in Singapore, where FDR participation rate is about 25 % among probands who have known pathogenic variants, aims to identify drivers of cost-effectiveness of CS protocols for FH. Four CS protocols, which vary in the application of genetic tests, were examined using a hybrid decision tree-Markov model. Sensitivity analyses were conducted to identify drivers of cost-effectiveness. Cascade acceptance rates are key drivers of cost-effectiveness. Other drivers include age of proband, prevalence of FH among probands, health-related quality of life loss with cardiovascular disease, timeliness of starting treatment post-screening, treatment effectiveness, cost of PCSK9i and discount rate for cost and QALY. With cascade acceptance rates observed in Singapore, among various screening protocols examined, probabilities of being cost-effective ranged from 86 % to 95 % when no access to PCSK9i and ranged from 75 % to 98 % when PCSK9i are provided. The most cost-effective protocol differs depending on cascade acceptance rates and whether PCSK9i is provided. For better cost-effectiveness of CS for FH, health systems need to look for ways to improve proband's willingness to share contact of their relatives and relatives' willingness to be screened and to lower the cost of novel treatment. Other ways to improve cost-effectiveness include to select age groups for proband screening, improve screening detection rate among probands, and start timely treatment post-screening.