title: Chronic pain, depression, and quality of life: correlations and predictive value of the SF-36.
abstract: OBJECTIVE
  Depression is a major barrier to effective pain relief. The SF-36 Health Survey may be useful as an outcome measure for chronic pain patients with and without depression. The study purpose was to determine the correlation between the SF-36 Mental Composite Scale t-score and depression type in chronic pain patients and the positive predictive value of the SF-36 in classifying depression type in chronic pain patients.
  
  
  METHODS
  Cross-sectional survey of chronic pain patients at baseline assessment.
  
  
  METHODS
  Interdisciplinary pain management center in the North Central United States.
  
  
  METHODS
  Two hundred forty-two consecutive, chronic noncancer pain patients.
  
  
  METHODS
  Assessments of patient-reported health-related quality of life (SF-36), pain, pain type and diagnoses, mental health diagnoses, and patient demographics.
  
  
  METHODS
  SF-36 Health Survey, pain diagnoses, and depression diagnoses.
  
  
  RESULTS
  Study participants were 160 women (66%) and 82 men (34%), 95% Caucasian, whose mean age was 46 (+/-0.8 SD) years (range: 19-83). All types and diagnoses of chronic pain were represented. The prevalence of major depressive disorder was 52%. The type of depression was highly correlated with SF-36 score (r=-0.567; P < 0.001). All chronic pain patients had very low SF-36 scores. Compared with U.S. population norms, chronic pain patients with and without depression had significantly lower SF-36 scores as measured by z-scores. Chronic pain patients with major depressive disorder had a significantly lower Mental Composite Score t-score than those with minor or no depression-34.1 and 47.6, respectively (P < 0.001). The positive predictive value of the SF-36 for differentiating major depression from minor or no depression was 98% (sensitivity=84.4%, specificity=93.9%).
  
  
  CONCLUSIONS
  The SF-36 Mental Composite Score and all subscales were highly correlated with depression type in chronic pain patients. The positive predictive value of the SF-36 in classifying depression type was high. The SF-36 may be a useful clinical tool to measure health-related quality of life in chronic pain patients. In addition, the SF-36 was able to detect major depression and demonstrate a dose-effect relationship between depression type (severity) and health-related quality of life in chronic pain patients.
authors.affiliation: Division of Education and Research, SMDC Pain Management Center, St. Mary's/Duluth Clinic Health System, Duluth, Minnesota 55805, USA. telliot@smdc.org
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Elliott
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Renier
authors.forename: Jeanette A
authors.initials: JA
authors.lastname: Palcher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000209:etiology* / Q000523:psychology; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology / Q000523:psychology*; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life