Assessment of Transition Plan Implementation and Provider Engagement Among Adults Living with Spinal Muscular Atrophy (SMA): Findings from a Cross-Sectional Survey.

INTRODUCTION: Advances in disease-modifying therapies have improved outcomes and survival in spinal muscular atrophy (SMA), resulting in a growing population of adolescents and young adults who must transition from pediatric to adult healthcare systems. Despite longstanding professional guidance supporting structured transition planning, limited data describe how these processes are implemented and experienced in SMA in the United States (U.S.). This study evaluated patient-reported experiences of transition planning and engagement with adult healthcare providers among young adults living with SMA. METHODS: A cross-sectional survey was distributed by email invitation to U.S. adults aged 18-29 years with 5q-SMA listed in the Cure SMA membership database, and interested individuals participated voluntarily. Descriptive analyses summarized transition status, exposure to structured transition elements, coordination practices, and experiences with adult providers. Respondents who had initiated transition were categorized by self-reported transition experience as Excellent/Very good/Good (EVG) or Fair/Poor (FP). RESULTS: Of 156 responses received (30.4% response rate), 137 met inclusion criteria, and 122 had initiated or completed transition. Among these, 59.0% reported fully transitioning to adult care. Exposure to structured preparation elements was limited overall but more commonly reported by EVG respondents compared with FP respondents, including readiness assessments (28.2% vs. 6.8%), discussions about transition planning (51.3% vs. 17.8%), and receipt of written transition plans (17.5% vs. 7.7%). FP respondents more commonly reported self-coordinating their transition (36.4% vs. 23.1%) and major challenges engaging with adult providers (26.3% vs. 4.6%) compared with EVG respondents. Nearly all respondents (98.0%) reported difficulty accessing adult clinicians with SMA-specific expertise. CONCLUSIONS: Transition experience among young adults with SMA was more closely associated with cumulative exposure to structured preparation elements than with a single transfer event. Broader implementation of provider-led transition practices may improve patient experience, strengthen engagement in adult SMA care, and support care coordination within adult systems where disease-specific expertise remains limited.