Why do some patients adhere worse? The role of frailty and depression in Parkinson disease.

Abstract

To investigate associations of frailty, depression, disease severity, and sociodemographic factors with treatment adherence, health behaviours, and disease-related knowledge in patients with Parkinson disease (PD), and to examine the relationship between health behaviours and quality of life. The study included 99 patients with PD (mean age: 70.11 ± 5.5 years; mean disease duration: 8.3 ± 5.68 years), all classified as Hoehn and Yahr stage 2 or higher. Standardized assessment tools included the Parkinson Disease Questionnaire (PDQ-39), Schwab and England Activities of Daily Living Scale (SE-ADL), Beck Depression Inventory (BDI), Adherence to Refills and Medications Scale (ARMS), Tilburg Frailty Indicator (TFI), Unified Parkinson Disease Rating Scale (UPDRS), Health Behaviour Inventory (HBI), and an author-designed clinical and sociodemographic questionnaire. Frailty was identified in 86.37% of participants. Non-frail patients demonstrated significantly better health behaviours (89.38 ± 8.25 vs 82.58 ± 10.16, p < 0.05) and treatment adherence (15.62 ± 2.18 vs 18.64 ± 4.08, p < 0.05) than frail patients. Better functional status was associated with higher treatment adherence (p < 0.001, ρ=-0.402), whereas greater severity of depressive symptoms was associated with poorer adherence (p < 0.001, ρ=0.352). Older patients were less likely to use the Internet to obtain information about PD (77.42% for 65 y.o, 41.94% for 66-70 y.o. and 24.32% for >70 y.o. group, p < 0.001), while higher educational attainment was positively associated with expanding knowledge about the disease (from 97.14% for higher education to 50% for primary, p = 0.001). Frailty, depressive symptoms, disease severity, and sociodemographic factors were associated with treatment adherence and health behaviours in patients with PD. Non-frail patients showed better adherence and healthier behaviours, while greater depressive symptom severity was associated with poorer adherence. Comprehensive PD care should address psychosocial, emotional, and behavioural factors alongside neurological management to support treatment adherence and patient care.