Trends in Spinal Muscular Atrophy–Related Mortality in Children in the United States, 1999–2023

Objectives There is a scarcity of nationwide data on trends in spinal muscular atrophy (SMA)–related mortality in the United States. We aimed to examine trends in SMA-related mortality in infants and children (≤4 years) between 1999 and 2023. Methods This retrospective population-based study used SMA-related death data from Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research records. The International Classification of Diseases codes G12.0, G12.1, G12.8, and G12.9 identified SMA. Joinpoint regression was used to analyze trends in age-adjusted mortality rates (AAMRs), quantified by annualized percent change (APC). Results There were 2,191 SMA-related deaths (46% female) among infants and children. The AAMR decreased from 7.64 per 1,000,000 in 1999 to 4.7 per 1,000,000 in 2016. From 2016 to 2018, the AAMR significantly declined from 4.7 to 1.54 (APC = −43.4, 95% CI−50.8 to −27.9). The SMA-AAMR stabilized from 2018 to 2023 (APC = −3.53, 95% CI−10.78 to 21.18). Discussion There was a steady decline in SMA-related mortality from 1999 to 2016 in the United States. This downtrend accelerated from 2016 to 2018, eventually reaching a plateau between 2018 and 2023. We were limited in demographic stratifications because rates are marked unreliable for counts fewer than 20 per the CDC Wide-ranging Online Data for Epidemiologic Research data use agreement.