Designing national programs for expanded carrier screening: Results from a discrete-choice experiment in Singapore

BackgroundCarrier screening for inherited genetic disorders can reduce the burden of conditions that lead to childhood morbidity and mortality, including thalassaemia, cystic fibrosis, and spinal muscular atrophy. To be successful, national carrier screening programs should aim to maximise uptake, which may depend on population preferences for screening characteristics. In this study, we aimed to determine how expanded carrier screening in Singapore should be designed based on operational factors including suggested copayments, wait times, and disorders included in screening panels. MethodsWe elicited stated preferences for the design of a hypothetical national carrier screening program with seven attributes from 500 Singaporeans of reproductive age (18 to 54). A discrete choice experiment was applied using 30 choice tasks with 3 alternatives per task, divided between 3 blocks. The mixed multinomial logit model was used to estimate willingness-to-pay for each attribute level. Predicted uptake for three plausible screening programs was assessed, with copayment amounts from $0 to $1,200 in increments of $30. Impact on the annual national budget was calculated as a function of 25,000 expected eligible couples per year. All costs were reported in 2026 SGD. ResultsRespondents showed the strongest preferences for cost, followed by the number of diseases included in the panel, then wait times, with limited impact of remaining attributes. With no copayments, predicted uptake ranged from 85% [95% CI: 83% to 87%] to 90% [88% to 92%] for the basic and utility-maximising screening programs, respectively. This declined to 61% [56% to 66%] and 69% [65% to 73%] and, respectively, at a copayment of $1,200 per test. The model predicted higher uptake if a selection of screening alternatives were available, compared to a single program. The budget impact was highly dependent on population eligibility, copayments, and couples decision-making processes, but was unlikely to exceed $22.5m [$19.0m to $26.6m] per year unless expanded beyond married couples. ConclusionsThere was high predicted demand for carrier screening even as copayments increased. Successful strategies to improve uptake may include reducing copays and wait times, increasing the number of screening options available to prospective parents, and increasing program eligibility beyond pre-conception married couples.