Greater and Clinically Meaningful Improvement in Health-Related Quality of Life After Device-Aided Therapy in Younger Patients Earlier Within Advanced Parkinson’s Disease: Real-World Evidence from the DATs-PD GETM Spanish Registry

Background and objective: Device-aided therapies (DATs) are established treatments for Parkinson’s disease (PD) with motor fluctuations insufficiently controlled by conventional therapy, but their optimal timing remains uncertain. We investigated whether younger patients earlier within advanced PD (yeaPD) experience greater health-related quality-of-life (HRQoL) improvement after DAT initiation. Methods: Data were obtained from the prospective, multicenter DATs-PD GETM Spanish Registry. yeaPD was defined as age ≤65 years, Hoehn and Yahr stage ≤2 in the ON state, and ≤5 years since motor fluctuation onset. HRQoL was assessed using the Parkinson’s Disease Questionnaire Summary Index (PDQ-39SI) at baseline and 6 ± 3 months. Results: Of 510 patients, 133 (26.1%) fulfilled yeaPD criteria. Paired data were available for 148 patients (36 yeaPD; 112 non-yeaPD). PDQ-39SI improved from 31.7 ± 13.8 to 21.9 ± 16.0 in yeaPD and from 38.5 ± 15.6 to 34.8 ± 17.1 in non-yeaPD (relative improvements: 30.9% vs. 9.6%; p = 0.032). The group-by-time interaction remained significant after adjustment for sex, principal caregiver, DAT type, time since PD diagnosis, and baseline levodopa equivalent daily dose (F = 4.565, p = 0.035), and after additionally adjusting for changes in motor and non-motor symptom burden (F = 4.460, p = 0.037). Clinically relevant HRQoL improvement occurred in 75.0% versus 53.6% (p = 0.023; OR 2.60, 95% CI 1.12–6.03). Mobility and stigmatization remained significant after multiplicity correction. Conclusions: DAT initiation while patients remain younger and functionally less advanced was associated with greater, clinically meaningful HRQoL improvement.