title: Performance status and depressive symptoms as predictors of quality of life in cancer patients. A structural equation modeling analysis.
abstract: OBJECTIVE
  This study aimed to examine whether depressive symptoms and performance status are independent predictors of both the physical and psychological domains of health-related quality of life (HRQoL) in cancer patients.
  
  
  METHODS
  A sample of 4020 cancer patients (mean age 58 years, 51% women) was evaluated. Depressive symptoms were measured with the patient health questionnaire and HRQoL with the European Organisation for Research and Treatment of Cancer quality of life questionnaire core 30. The impact of the illness on everyday activities was assessed with physician ratings of both the Karnofsky performance status and the Eastern Cooperative Oncology Group performance status. The simultaneous effects of depression and performance status on quality of life outcomes were estimated using structural equation modeling.
  
  
  RESULTS
  Both depressive symptoms and performance status independently predicted the physical and psychological domains of HRQoL. However, the impact of depressive symptoms on the physical HRQoL was stronger than the impact of performance status on the psychological HRQoL.
  
  
  CONCLUSIONS
  Our results suggest that comorbid depressive symptoms are independently associated with both physical and psychological HRQoL in cancer patients after controlling for the physician-rated performance status. Thus, comorbid depression should be taken into account when evaluating reduced HRQoL in cancer patients. To support a causal impact of depression on HRQoL, intervention studies are needed to show that improving depression enhances cancer patients' HRQoL.
authors: Department of Medical Psychology and Psychotherapy, Medical Sociology and Rehabilitation Sciences, and Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany.
authors: Hermann
authors: H
authors: Faller
authors: Department of Medical Psychology and Medical Sociology, Section of Psychosocial Oncology, University Medical Center Leipzig, Leipzig, Germany.|Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Mainz, Mainz, Germany.
authors: Elmar
authors: E
authors: Brähler
authors: Department and Outpatient Clinic of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Martin
authors: M
authors: Härter
authors: Division of Psychooncology, Department for Psychosomatic and General Clinical Medicine, University Hospital Heidelberg, Heidelberg, Germany.
authors: Monika
authors: M
authors: Keller
authors: Department and Outpatient Clinic of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Holger
authors: H
authors: Schulz
authors: Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Karl
authors: K
authors: Wegscheider
authors: Department of Psychooncology, Tumor Biology Center, University of Freiburg, Freiburg, Germany.
authors: Joachim
authors: J
authors: Weis
authors: Department of Psychooncology, Tumor Biology Center, University of Freiburg, Freiburg, Germany.
authors: Anna
authors: A
authors: Boehncke
authors: Department of Medical Psychology and Psychotherapy, Medical Sociology and Rehabilitation Sciences, and Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany.
authors: Matthias
authors: M
authors: Richard
authors: Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Susanne
authors: S
authors: Sehner
authors: Department and Outpatient Clinic of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Uwe
authors: U
authors: Koch
authors: Department of Medical Psychology and Medical Sociology, Section of Psychosocial Oncology, University Medical Center Leipzig, Leipzig, Germany.|Department and Outpatient Clinic of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Anja
authors: A
authors: Mehnert
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology*; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009369:Neoplasms / Q000453:epidemiology / Q000523:psychology* / Q000628:therapy; D011788:Quality of Life