PT  - JOURNAL ARTICLE
AU  - Laura Manea
AU  - Simon Gilbody
AU  - Dean McMillan
TI  - Optimal cut-off score for diagnosing depression with the Patient Health Questionnaire (PHQ-9): a meta-analysis
AID  - 10.1503/cmaj.110829
DP  - 2012 Feb 21
TA  - Canadian Medical Association Journal
PG  - E191--E196
VI  - 184
IP  - 3
4099  - http://www.cmaj.ca/content/184/3/E191.short
4100  - http://www.cmaj.ca/content/184/3/E191.full
SO  - CMAJ2012 Feb 21; 184
AB  - Background: The brief Patient Health Questionnaire (PHQ-9) is commonly used to screen for depression with 10 often recommended as the cut-off score. We summarized the psychometric properties of the PHQ-9 across a range of studies and cut-off scores to select the optimal cut-off for detecting depression.Methods: We searched Embase, MEDLINE and PsycINFO from 1999 to August 2010 for studies that reported the diagnostic accuracy of PHQ-9 to diagnose major depressive disorders. We calculated summary sensitivity, specificity, likelihood ratios and diagnostic odds ratios for detecting major depressive disorder at different cut-off scores and in different settings. We used random-effects bivariate meta-analysis at cutoff points between 7 and 15 to produce summary receiver operating characteristic curves.Results: We identified 18 validation studies (n = 7180) conducted in various clinical settings. Eleven studies provided details about the diagnostic properties of the questionnaire at more than one cut-off score (including 10), four studies reported a cut-off score of 10, and three studies reported cut-off scores other than 10. The pooled specificity results ranged from 0.73 (95% confidence interval [CI] 0.63–0.82) for a cut-off score of 7 to 0.96 (95% CI 0.94–0.97) for a cut-off score of 15. There was major variability in sensitivity for cut-off scores between 7 and 15. There were no substantial differences in the pooled sensitivity and specificity for a range of cut-off scores (8–11).Interpretation: The PHQ-9 was found to have acceptable diagnostic properties for detecting major depressive disorder for cut-off scores between 8 and 11. Authors of future validation studies should consistently report the outcomes for different cut-off scores.See related commentary by Kroenke at www.cmaj.ca/lookup/doi/10.1503/cmaj.112004