title: The effects of pain severity on health-related quality of life: a study of Chinese cancer patients.
abstract: BACKGROUND
  The health-related functioning of patients with cancer is compromised by several factors, including the disease process, treatment, and the various symptoms that are produced by both disease and treatment. This study was designed to specify the relationship between patients' pain severity and their self-reported quality of life.
  
  
  METHODS
  The study enrolled 216 consecutive consenting adult patients from 2 Chinese cancer centers with pathologically-diagnosed metastatic cancer who could understand and complete the self-report measures. The majority had cancer-related pain and were receiving analgesics. The Chinese version of the Brief Pain Inventory was used to assess the severity and interference of pain. A Chinese translation of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) was used to assess health-related functional status. Patients' physicians completed a form that indicated characteristics of the patients' cancer, Eastern Cooperative Oncology Group performance status, pain, and current pain treatment.
  
  
  RESULTS
  Increasing severity of pain was associated with worsening health-related functioning, even when an estimate of disease severity was taken into account. The correlation between pain severity and impairment was nonlinear. The functional health and well-being of cancer patients with no or mild pain was significantly less impaired than that of patients with moderate or severe pain. The impairment of patients with moderate and severe pain did not differ.
  
  
  CONCLUSIONS
  Pain severity is an important variable to be taken into account when quality of life outcome measures are considered. The functioning of cancer patients with well-controlled (mild) pain did not differ significantly from that of patients without pain. Providing pain relief should significantly improve the functional status of cancer patients.
authors.affiliation: Pain Research Group, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: X S
authors.initials: XS
authors.lastname: Wang
authors.forename: C S
authors.initials: CS
authors.lastname: Cleeland
authors.forename: T R
authors.initials: TR
authors.lastname: Mendoza
authors.forename: M C
authors.initials: MC
authors.lastname: Engstrom
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: X
authors.initials: X
authors.lastname: Hao
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: X S
authors.initials: XS
authors.lastname: Ren
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001294:Attitude to Health; D001859:Bone Neoplasms / Q000556:secondary; D001943:Breast Neoplasms / Q000523:psychology; D002681:China; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000523:psychology; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary; D008175:Lung Neoplasms / Q000523:psychology / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000523:psychology*; D010148:Intractable Pain / Q000523:psychology*; D011788:Quality of Life; D015203:Reproducibility of Results