Longitudinal Changes in Patient- and Clinical-Reported Outcomes in Early Spinocerebellar Ataxia Types 1, 2, 3, and 6 from the IDEA Study

Background: Clinical outcomes assessments (COAs) in spinocerebellar ataxia (SCA) need to be standardized, ataxia-specific, sensitive to change, clinically relevant, and meaningful to patients. Objectives: To evaluate the longitudinal 1- and 2-year performances of different patient reported outcomes, including the Patient Reported Outcome Measure of Ataxia (PROM-Ataxia), and clinician reported outcomes, including FARS and SARA, in those with early manifest symptoms of SCA 1, 2, 3, and 6. Methods: We studied 53 patients with early stage SCA1-3 and SCA6 from The Instrumented Data Exchange for Ataxia Study and 24 age-matched healthy controls. Participants were seen every 6 months for 2 years. Mixed models were used to estimate change over 12- and 24-months of follow-up. Changes on the FARS-FS and PGI-C were used as anchors to estimate meaningful changes. Results: Among persons with SCA, mean age was 48.7 years and mean SARA score was 9.3. Few measures showed statistically significant changes at 12 months. At 24-months, the FARS-ADL, PROM-Ataxia total, PROM-Ataxia physical, and PROM-Ataxia ADL scores showed the strongest associations of change. Conclusions: Patient reported or derived outcome measures, such as FARS-ADL and ADL sub domain of the PROM-Ataxia, can capture longitudinal change in patients’ symptom experience over a 2-year period and its impact on daily activities, even in those with early disease. More work is needed to identify outcomes that reliably capture change earlier.