Development and validation of TreatHSP-QoL – a patient-reported outcome measure for health-related quality of life in hereditary spastic paraplegia

Abstract

Abstract Background. Hereditary spastic paraplegia (HSP) is a rare neurodegenerative disease that lacks specific and validated patient-centered outcome measures (PCOMs). We aimed to develop and validate a health-related quality of life (HRQoL) questionnaire specific to HSP (“TreatHSP-QoL”) that could be used as a PCOM. Results. The pilot-items of the TreatHSP-QoL (45 five-level Likert scale items, with values per item between 0–4) were developed based on a qualitative data analysis of 54 semi-structured interviews, conducted in person with 36 HSP patients and 18 caregivers. It was then reduced and modified through the validation process to 25 items. The main validation was performed using the online questionnaire in 242 HSP patients and 56 caregivers. The exploratory factor analysis defined five subdomains. Cronbach’s alpha ranged from 0.57–0.85 for the subdomains and reached 0.85 for the total score. The test-retest correlation reached 0.86. Correlations with the EuroQol-5 Dimension (5 levels) (EQ-5D-5L) and Friedreich Ataxia Rating Scale-Activities of Daily Living (FARS-ADL) questionnaires varied strongly among the subdomains, with the total scores reaching 0.53 and − 0.45, respectively. The caregiver-patient response correlation ranged between 0.64–0.82 for subdomains and reached 0.65 for the total score. Conclusions. TreatHSP-QoL can be used in high-quality clinical trials and clinical practice as a disease-specific PCOM (i.e., HRQoL measure) and is also applicable as a proxy questionnaire. Score values between 0-100 can be reached, where higher value represents better HRQoL. The variable correlations to the EQ-5D-5L and FARS-ADL support the specificity for HSP. All in all, the results demonstrate good validity and reliability for this new patient-centered questionnaire for HSP.