title: Influence of disease severity on fatigue in patients with Parkinson's disease is mainly mediated by symptoms of depression.
abstract: OBJECTIVE
  Fatigue is a frequent non-motor complaint of patients with Parkinson's disease (PD). Despite increasing knowledge on fatigue, the factors leading to its development are still not recognised. The aim of this investigation was to test, using structural equation modelling, the hypothesis that the influence of disease severity on fatigue is mediated by symptoms of depression in patients with PD.
  
  
  METHODS
  The sample consisted of 190 PD patients (93 men, 48.9%, mean age 68.2±9.3 years, mean disease duration 6.4±4.7 years) recruited from hospitals and outpatient clinics in the East Slovakia region. The Multidimensional Fatigue Inventory, the Hospital Anxiety and Depression Scale and the Unified Parkinson's Disease Rating Scale were used. LISREL was used to analyse the data.
  
  
  RESULTS
  Disease severity was directly associated with symptoms of depression (β=0.26) and directly affected fatigue in terms of increased levels of general fatigue (β=0.35), physical fatigue (β=0.22), reduced activity (β=0.31) and mental fatigue (β=0.29), but did not directly influence reduced motivation. Symptoms of depression mediated the impact of disease severity on general fatigue (β=0.25), on reduced activity (β=0.31) and on mental fatigue (β=0.28), but not on physical fatigue. Reduced motivation was not mediated, but directly influenced by more symptoms of depression (β=0.82).
  
  
  CONCLUSIONS
  Since increased symptoms of depression mediate the impact of disease severity on three domains of fatigue in PD patients, disease management should focus on the treatment of PD and symptoms of depression.
authors: Department of Community and Occupational Medicine, University Medical Center Groningen, University of Groningen, The Netherlands.
authors: Jitse P
authors: JP
authors: van Dijk
authors: Eva
authors: E
authors: Havlikova
authors: Jaroslav
authors: J
authors: Rosenberger
authors: Iveta
authors: I
authors: Nagyova
authors: Matej
authors: M
authors: Skorvanek
authors: Zuzana
authors: Z
authors: Gdovinova
authors: Willem
authors: W
authors: Lok
authors: Johan W
authors: JW
authors: Groothoff
authors: Berrie
authors: B
authors: Middel
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003863:Depression / Q000209:etiology / Q000523:psychology*; D005221:Fatigue / Q000209:etiology / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000150:complications / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D011795:Surveys and Questionnaires