Estimating Health State Utilities from a Longitudinal SMA Cohort

OBJECTIVES: The past five years have yielded many important advances in care, treatment and lifespan in individuals living with spinal muscular atrophy (SMA). Despite improvements in research and innovation, it is important to understand outcomes that matter most to patients and ways to measure changes that can be used in clinical care and research settings. Health-related quality of life (HRQOL) instruments enable benchmarking and assessing changes across populations. One such instrument is the Health Utilities Index Mark 3 (HUI3) which provides a comprehensive framework to measure health status summarized in a single utility score that can be used in economic evaluations.

METHODS: Since 2017, Cure SMA, a patient advocacy organization that provides support and funding for care and treatment for those with spinal muscular atrophy (SMA), has hosted an annual community update survey (CUS) for caregivers and affected individuals. The CUS captures data such as demographics, treatment experience and HRQOL measures, including the HUI3. This study utilized a mixed-effects linear regression model to explore associations between HUI3 scores and multiple covariates in individuals diagnosed with SMA. The model could be useful for estimating the value of different interventions and treatments used in SMA.

RESULTS: Key findings indicate that severe SMA Type 1 is associated with lower HUI3 scores, while Types 3 and 4 exhibit higher scores compared to Type 2. Those who receive treatment have associations with higher HUI3 scores compared to those not receiving treatment. Having commercial insurance is linked to higher HUI3 scores than having public insurance. Age during the survey is negatively associated, suggesting that as age increases, HUI3 score tends to decrease.

CONCLUSIONS: In summary, the model underscores the influence of SMA type, treatment modality, age, insurance category, and survey year on HUI3 scores, providing valuable insights into factors impacting HRQOL in individuals with SMA.