title: The validity of the Patient Health Questionnaire for screening depression in chronic care patients in primary health care in South Africa.
abstract: BACKGROUND
  People with chronic health conditions are known to have a higher prevalence of depressive disorder. The Patient Health Questionnaire (PHQ-9) is a widely-used screening tool for depression which has not yet been validated for use on chronic care patients in South Africa.
  
  
  METHODS
  A sample of 676 chronic care patients attending two primary health facilities in North West Province, South Africa were administered the PHQ-9 by field workers and a diagnostic interview (the Structured Clinical Interview for DSM-IV) (SCID) by clinical psychologists. The PHQ-9 and the PHQ-2 were evaluated against the SCID, as well as for sub-samples of patients who were being treated for HIV infection and for hypertension.
  
  
  RESULTS
  Using the SCID, 11.4 % of patients had major depressive disorder. The internal consistency estimate for the PHQ-9 was 0.76, with an area under the receiver operator curve (AUROC) of 0.85 (95 % CI 0.82-0.88), which was higher than the AURUC for the PHQ-2 (0.76, 95 % CI 0.73-0.79). Using a cut-point of 9, the PHQ-9 has sensitivity of 51 % and specificity of 94 %. The PHQ-9 AUROC for the sub-samples of patients with HIV and with hypertension were comparable (0.85 and 0.86, respectively).
  
  
  CONCLUSIONS
  The PHQ-9 is useful as a screening tool for depression among patients receiving treatment for chronic care in a public health facility.
authors.affiliation: School of Applied Human Sciences, University of KwaZulu-Natal, Durban, South Africa. arvin.bhana@gmail.com.
authors.forename: Arvin
authors.initials: A
authors.lastname: Bhana
authors.affiliation: Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK. Sujit.Rathod@lshtm.ac.uk.
authors.forename: Sujit D
authors.initials: SD
authors.lastname: Rathod
authors.affiliation: School of Applied Human Sciences, University of KwaZulu-Natal, Durban, South Africa. Selohilwe@ukzn.ac.za.
authors.forename: One
authors.initials: O
authors.lastname: Selohilwe
authors.affiliation: School of Applied Human Sciences, University of KwaZulu-Natal, Durban, South Africa. Kathree@ukzn.ac.za.
authors.forename: Tasneem
authors.initials: T
authors.lastname: Kathree
authors.affiliation: School of Applied Human Sciences, University of KwaZulu-Natal, Durban, South Africa. PETERSENI@ukzn.ac.za.
authors.forename: Inge
authors.initials: I
authors.lastname: Petersen
mesh_terms: D000328:Adult; D003865:Major Depressive Disorder / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000523:psychology; D006801:Humans; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D012680:Sensitivity and Specificity; D013019:South Africa; D011795:Surveys and Questionnaires / Q000592:standards*