Development and Validation of Quality of Life in Parkinson's Disease Instrument

CONTEXT: Parkinson's disease (PD) has devastating effects on quality of life (QoL), but there is no instrument that has been developed for Hindi-speaking persons with Parkinson's disease (PWP). OBJECTIVE: The objective of this study was to develop and validate an instrument in Hindi language to measure health-related QoL (HRQoL) in PWP. SUBJECTS AND METHODS: Literature review and interviews of stakeholders were done to create a pool of 68 items to develop a questionnaire. Self-rated global QoL item was also included in the questionnaire. Questionnaire was tested on 300 Hindi-speaking PWP. Item reduction was achieved through factor analysis and clinimetrics to finalize the QoL in PD (QLPD) instrument. Validity and reliability of the QLPD were tested. RESULTS: “QLPD” is a 45-item instrument with nine subscales, namely, activities of daily living, mobility, psychological, fear, social, family, treatment, finance, and nonmotor symptom subscales. Internal consistency of QLPD's summary score and all subscales except treatment subscale was high (α = 0.74–0.94). Intraclass correlation coefficient between summary score and global QoL was 0.79. Summary score and subscale scores were significantly different (P < 0.0001) for predefined five categories on global QoL (very good to very bad). QLPD subscales exhibited good convergent and divergent validity with subscales of 39-item PD questionnaire and short form-36 scale. Higher Hoehn and Yahr stage, lower monthly per capita income, and higher levodopa equivalent daily dosage were found to be independently associated with poor HRQoL. CONCLUSION: QLPD is a valid and reliable instrument to measure HRQoL in Hindi-speaking PWP.