Validation study of the Parkinson’s Fatigue Scale in advanced Parkinson’s disease

Abstract

Purpose: 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 (r_S=0.65) and item 4 of the Non-Motor Symptoms Scale (r_S=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

Abbreviation list

APD, Advanced Parkinson’s disease; AS, Apathy scale; BAI, Beck Anxiety Inventory; BDI-II, Beck Depression Inventory-II; LCIG, Levodopa-Carbidopa Intestinal Gel; CGI-S, Clinical Global Impression–Severity; HY, Hoehn & Yahr stage; LEDD, Levodopa equivalent daily dose; NMSS, Non-Motor Symptoms Scale; PD, Parkinson’s disease; PDQ-39, Parkinson’s Disease Questionnaire-39 items; PFS-16, Parkinson’s Fatigue Scale; QoL, Health-related quality of lifep; S&E, Schwab and England Scale; UPDRS, Unified Parkinson’s Disease Rating Scale; ZBI, Zarit Burden Inventory.

Data sharing statement

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

The authors would like to acknowledge the members of the ADEQUA Study Group responsible for recruitment in the clinical centers: Virgen de las Nieves Hospital: Francisco Escamilla Sevilla; Torrecárdenas Hospital: Jesús Olivares; Burgos Hospital Center: Esther Cubo; Arquitecto Marcide Hospital: Diego Santos; Son Espases Hospital: Bárbara Vives; Puerta del Mar Hospital: Miguel Moya, Raúl Espinosa Rosso; Santa Creu i Sant Pau Hospital: Berta Pascual; Vall d’Hebron Hospital: Oriol de Fabregues; Valladolid Hospital: Javier Marco; Elche General Hospital: María Álvarez, Eric Freire; La Fe Hospital: Irene Martínez; Santa Lucía Hospital: Juan José Soria; Navarra Hospital Center: Pedro Luis Clavero, Icíar Gastón; San Pedro Alcántara Hospital: Gonzalo Gámez-Leyva, Montserrat Gómez; Bellvitge Hospital: Matilde Calopa; Parc Taulí Hospital: Tania Delgado.

Author contributions

The persons in the list of authors of this manuscript meet the following requirements:

1. They did substantial contributions to conception and design, data acquisition, or data analysis and interpretation;

2. They drafted the article or critically revised it for important intellectual content;

3. They gave their final approval of the version to be published; and

4. They agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of the work are appropriately investigated and resolved.

Disclosure

P. Martinez-Martin received honoraria from Editorial Viguera for lecturing in courses; International Parkinson and Movement Disorder Society for management of the Program on Rating Scales; Air Liquide, HM Hospitales de Madrid, and Zambon for advice in clinic epidemiological studies; license fee payments for the King’s Parkinson’s Disease Pain scale; and grant from the International Parkinson and Movement Disorder Society to attend the congress of the society in 2017. J.M. Arbelo González has received honoraria from AbbVie, Zambon, Bial, and Teva. M. J. Catalán has received honoraria for speaking services and research from AbbVie Laboratories and Merz. F. Valldeoriola has received honoraria for speaking services and advisory boards from AbbVie, Zambon, Teva, Medtronic, and Boston Scientific. The authors report no other conflicts of interest in this work.