Reliability and Validity of the HD-PRO-Triad^TM, a Health-Related Quality of Life Measure Designed to Assess the Symptom Triad of Huntington's Disease

Background: Huntington's disease (HD), is a neurodegenerative disorder that is associated with cognitive, behavioral, and motor impairments that diminish health related quality of life (HRQOL). The HD-PRO-TRIADTM is a quality of life measure that assesses health concerns specific to individuals with HD. Preliminary psychometric characterization was limited to a convenience sample of HD participants who completed measures at home so clinician-ratings were unavailable. Objectives: The current study evaluates the reliability and validity of the HD-PRO-TRIADTM in a well-characterized sample of individuals with HD. Methods: Four-hundred and eighty-two individuals with HD (n = 192 prodromal, n = 193 early, and n = 97 late) completed the HD-PRO-TRIADTM questionnaire. Clinician-rated assessments from the Unified Huntington Disease Rating Scales, the short Problem Behaviors Assessment, and three generic measures of HRQOL (WHODAS 2.0, RAND-12, and EQ-5D) were also examined. Results: Internal reliability for all domains and the total HD-PRO-TRIADTM was excellent (all Cronbach's > 0.93). Convergent and discriminant validity were supported by significant associations between the HD-PRO-TRIADTM domains, and other patient reported outcome measures as well as clinician-rated measures. Known groups validity was supported as the HD-PRO-TRIADTM differentiated between stages of the disease. Floor and ceiling effects were generally within acceptable limits. There were small effect sizes for 12-month change over time and moderate effect sizes for 24-month change over time. Conclusions: Findings support excellent internal reliability, convergent and discriminant validity, known groups validity, and responsiveness to change over time. The current study supports the clinical efficacy of the HD-PRO-TRIADTM. Future research is needed to assess the test-retest reliability of this measure.