title: Modifiable and fixed factors predicting quality of life in people with colorectal cancer.
abstract: BACKGROUND
  People with colorectal cancer have impaired quality of life (QoL). We investigated what factors were most highly associated with it.
  
  
  METHODS
  Four hundred and ninety-six people with colorectal cancer completed questionnaires about QoL, functioning, symptoms, co-morbidity, cognitions and personal and social factors. Disease, treatment and co-morbidity data were abstracted from case notes. Multiple linear regression identified modifiable and unmodifiable factors independently predictive of global quality of life (EORTC-QLQ-C30).
  
  
  RESULTS
  Of unmodifiable factors, female sex (P<0.001), more self-reported co-morbidities (P=0.006) and metastases at diagnosis (P=0.036) significantly predicted poorer QoL, but explained little of the variability in the model (R(2)=0.064). Adding modifiable factors, poorer role (P<0.001) and social functioning (P=0.003), fatigue (P=0.001), dyspnoea (P=0.001), anorexia (P<0.001), depression (P<0.001) and worse perceived consequences (P=0.013) improved the model fit considerably (R(2)=0.574). Omitting functioning subscales resulted in recent diagnosis (P=0.002), lower perceived personal control (P=0.020) and travel difficulties (P<0.001) becoming significant predictors.
  
  
  CONCLUSIONS
  Most factors affecting QoL are modifiable, especially symptoms (fatigue, anorexia, dyspnoea) and depression. Beliefs about illness are also important. Unmodifiable factors, including metastatic (or unstaged) disease at diagnosis, have less impact. There appears to be potential for interventions to improve QoL in patients with colorectal cancer.
authors.affiliation: Centre of Academic Primary Care, University of Aberdeen, Foresterhill Health Centre, Westburn Road, Aberdeen AB25 2AY, UK. n.gray@abdn.ac.uk
authors.forename: N M
authors.initials: NM
authors.lastname: Gray
authors.forename: S J
authors.initials: SJ
authors.lastname: Hall
authors.forename: S
authors.initials: S
authors.lastname: Browne
authors.forename: U
authors.initials: U
authors.lastname: Macleod
authors.forename: E
authors.initials: E
authors.lastname: Mitchell
authors.forename: A J
authors.initials: AJ
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Johnston
authors.forename: S
authors.initials: S
authors.lastname: Wyke
authors.forename: L
authors.initials: L
authors.lastname: Samuel
authors.forename: D
authors.initials: D
authors.lastname: Weller
authors.forename: N C
authors.initials: NC
authors.lastname: Campbell
mesh_terms: D000368:Aged; D000855:Anorexia / Q000453:epidemiology; D001294:Attitude to Health; D015179:Colorectal Neoplasms / Q000473:pathology / Q000523:psychology*; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology; D005221:Fatigue / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011788:Quality of Life; D012919:Social Behavior; D011795:Surveys and Questionnaires