Patient Related Outcome Measures (Apr 2019)
Validation study of the Parkinson’s Fatigue Scale in advanced Parkinson’s disease
Abstract
Pablo Martinez-Martin,1,2 John B Wetmore,1 José Matías Arbelo,3 María José Catalán,4 Francesc Valldeoriola,5 Carmen Rodriguez-Blazquez1,21National Center of Epidemiology, Carlos III Institute of Health, Madrid, Spain; 2Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Carlos III Institute of Health, Madrid, Spain; 3Movement Disorders Unit, Hospital Universitario Insular de Gran Canaria, Las Palmas de Gran Canaria, Spain; 4Department of Neurology, Hospital Clínico San Carlos, Madrid, Spain; 5Department of Neurology, Hospital Clínico de Barcelona, Barcelona, SpainPurpose: To validate the Parkinson’s Fatigue Scale (PFS-16) in advanced Parkinson Disease (APD) patients using the scale’s Spanish version.Patients and methods: In a clinical study for Levodopa-Carbidopa Intestinal Gel (LCIG), 59 patients were assessed over six months using the PFS-16 and other instruments. The psychometric properties of the PFS-16 were then analyzed.Results: Patients (60.7% men) were aged 68.02±7.43 years. PD duration was 12.57±5.97 years. Median Hoehn and Yahr (HY) stage of patients in “on” was 2 (range: 1–4). There were excellent data quality and acceptability for the PFS-16 as a whole, except for moderate-to-high ceiling effects in its items. Two factors explained 67% of the variance, yet parallel analysis demonstrated the unidimensional nature of the PFS-16, whose internal consistency was satisfactory (Cronbach’s alpha=0.93; item homogeneity coefficient=0.19, and item total-corrected correlations=0.50–0.84). PFS-16 total score showed moderate-to-high correlations with fatigue-specific questions within clinical tools, namely item 20 of the Beck Depression Inventory (rS=0.65) and item 4 of the Non-Motor Symptoms Scale (rS=0.33). Weak-to-moderate correlations were observed between the PFS-16 and measures of anxiety, depression, apathy, and quality of life. There were no significant differences in PFS-16 total scores when grouped by age, sex, time from diagnosis, HY, and CGI-S. After treatment with LCIG, the relative change in PFS-16 total score was −17.6% and the effect size (Cohen’s d) was 0.92. Moderate correlations between changes in the PFS-16 and several other clinical tools were also found.Conclusion: In APD patients, the PFS-16 showed satisfactory acceptability, internal consistency, construct validity, and responsiveness.Keywords: Parkinson’s disease, fatigue, Parkinson’s Fatigue Scale, PFS-16, advanced Parkinson’s disease, psychometric properties
