F32 Exploring the feasibility of a novel and efficient trial design for the evaluation of long-term physical activity and exercise outcomes in people with huntington’s disease

Background Evidence of best practice for long term physical activity Huntington’s disease (HD) is lacking, due in part, to inherent challenges in the delivery and evaluation of such life-style interventions. Aim To investigate the feasibility of a nested randomized controlled trial (RCT) of physical activity into Enroll-HD, an established HD cohort study. Methods We conducted a ‘Trial within a Cohort’ (TWiC) evaluation of an exercise intervention compared to usual activity in individuals with early-mid stage HD. All participants completed their usual Enroll-HD assessments and PACE-HD assessments, which included measures of fitness (predicted maximal oxygen uptake) and self-reported and quantitative measures of physical activity. We explored the use of propensity score weighting to compare the individuals in the intervention arm of the RCT to those in the cohort. Results Of the 274 participants screened, 204 met the inclusion criteria and of those, 54 (26.5%) declined to participate and 34 (16.7%) were not contactable. Recruitment targets were only narrowly missed; 59/60 (98.3%) for the cohort and 57/60 (93.5%) for the RCT. Retention rates at 12 months were ~ 85 in both groups. Percentage (%) data completeness for outcomes measures at baseline ranged from 42.3-100% and at 12 month follow up from 19.2–85.2 %. Imbalances in pretreatment confounders for the cohort and the RCT could not to be addressed via propensity score weighting likely due to small sample sizes. Conclusion A targeted recruitment strategy was instrumental in achieving target recruitment; retention at 12 months was excellent. Pre-specified criteria for minimum dataset data completion (both PACE-HD and linked Enroll-HD datasets) were met. The TWiC design, with linkage to Enroll-HD, is feasible for long-term physical activity evaluation in HD provided sample size requirements can be achieved. *PACE-HD & Enroll-HD site principal investigators Teresa Montojo. Neurology Department, Fundacion Jimenez Diaz, Madrid, Spain. Jesus Miguel Ruiz Idiago. Neuropsychiatry Unit, Hospital Mare de Deu de la Merce, Barcelona, Spain. Department of Psychiatry and Forensic Medicine, Universitat Autonoma de Barcelona, Spain. Julie Hershberg. University of Southern California, Division of Biokinesiology and Physical Therapy. Re+active physical therapy & wellness, Los Angeles, CA, USA. Yvette Bordelon. Department of Neurology, University of California, Los Angeles, CA, USA. Karen Marder, Columbia University Irving Medical Center, New York, NY, USA. Lori Quinn, Teachers College, Columbia University, New York, NY, USA. Ralf Reilmann. George-Huntington-Institute and Institute for Clinical Radiology, University of Munster, Munster, Germany. Kathrin Reetz. University Hospital Aachen, Germany. Bernhard Landwehrmeyer. University Hospital Ulm, Germany.