A cost-utility analysis of newborn screening for spinal muscular atrophy in Canada

Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by the loss of the SMN1 gene, with an estimated birth prevalence of about 1 in 10,000. Early intervention with disease-modifying therapies (DMTs) significantly improves outcomes. This study evaluates the economic implications and health benefits of newborn screening (NBS) for SMA in Canada from the societal perspective.

A decision analytic model was developed, which combined a decision tree for the screening algorithm and a Markov model for long-term health outcomes. The Markov model included health states based on WHO motor milestones. The population cohort of 357,903 live newborns reflects the 2022-2023 births in Canada. Screening is performed on dried blood spot testing which evaluates for biallelic deletions in SMN1. Cost inputs encompassed treatment and health state costs, while utility values reflected quality of life in each health state.

NBS for SMA is expected to identify 37.1 (95% CI: 15.0, 70.7) newborns annually in Canada. Our analysis over a lifetime horizon and a discount rate of 1.5% shows NBS and early treatment has an incremental cost of -$146,187,000 (95% CI: -249,773,777 to - 17,890,034) and incremental benefit of 872 (95% CI: -193, 2329) quality-adjusted life years (QALYs) compared to no NBS and late treatment. This resulted in a mean ICER value of -$173,572/QALY.

The decision analytic model indicated that overall NBS is cost-saving and more effective than no NBS and late treatment in the Canadian health system.