Depression as Measured by PHQ-9 Versus Clinical Diagnosis as an Independent Predictor of Long-Term Mortality in a Prospective Cohort of Medical Inpatients.
BACKGROUND
Depression has been associated with higher rates of mortality in medical patients. The aim of the study was to evaluate the impact of depression in medical inpatients on the rate of mortality during a prolonged follow-up period.


METHODS
This is a prospective follow-up study of a cohort of medical inpatients assessed during 1997-1998 in medical and surgical units at a tertiary university hospital in Spain and followed-up for a period ranging between 16.5 and 18 years. Eight hundred three patients were included; 420 (52.3%) were male, and the mean (SD) age was 41.7 (13.8) years. Main outcome was death for any cause during follow-up. The original full Patient Health Questionnaire (PHQ) was administered at baseline as self-report from which the PHQ-9 was derived. Depressive disorders were assessed using PHQ-9 and a structured clinical interview (Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition).


RESULTS
Depressive disorders as defined by PHQ-9 were detected in 206 patients (25.7%), 122 (15.2%) of them fulfilling criteria for major depression. During follow-up, 152 patients (18.9%) died. A PHQ score indicating the presence of major depressive disorder predicted increased mortality (hazard ratio [HR], 2.44; 95% CI, 1.39-4.29), even after adjusting for important demographic and clinical variables. Similarly, the PHQ-9 score as a continuous measure of depression severity predicted increased mortality (HR, 1.06; 95% CI, 1.02-1.10). Results were similar for clinical interview diagnoses of major depression (HR, 2.07; 95% CI, 1.04-4.09).


CONCLUSIONS
Medical inpatients with a PHQ depressive disorder had a nearly 2-fold higher risk of long-term mortality, even after adjustment for several confounders. Depression severity as represented by the PHQ-9 score was also a risk factor.
From the Department of Psychiatry and Legal Medicine (Martin-Subero, Diez-Quevedo, Lorán), Universitat Autonoma de Barcelona, Badalona, Spain; Psychiatric Unit, Germans Trias i Pujol University Hospital (Martin-Subero, Diez-Quevedo, Rangil, Lorán, Mateu), Badalona, Spain; FIDMAG Germanes Hospitalaries Research Foundation (Martin-Subero), Barcelona, Spain; Carlos III Health Institute (Martin-Subero), Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain; Department of Medicine (Kroenke), Indiana University, Indianapolis, Indiana; Regenstrief Institute and VA HSR&D Center for Health Information and Communication (Kroenke), Indianapolis, Indiana; Heart Failure Unit, Department of Cardiology (de Antonio, Lupon), Germans Trias i Pujol University Hospital, Badalona, Spain; Carlos III Health Institute (Morillas, Planas), Centro de Investigación Biomédica en Red de Hepatologia (CIBEREHD), Madrid (Spain); Liver Unit, Department of Gastroenterology (Morillas, Planas), Germans Trias i Pujol University Hospital, Badalona, Spain; Department of Medicine (Lupon, Planas), Universitat Autonoma de Barcelona, Badalona, Spain; and Department of Clinical Documentation (Navarro), Germans Trias i Pujol University Hospital, Badalona, Spain.
Marta
M
Martin-Subero
Kurt
K
Kroenke
Crisanto
C
Diez-Quevedo
Teresa
T
Rangil
Marta
M
de Antonio
Rosa Maria
RM
Morillas
Maria Eulalia
ME
Lorán
Cristina
C
Mateu
Josep
J
Lupon
Ramon
R
Planas
Ruth
R
Navarro
D000328:Adult; D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D003866:Depressive Disorder / Q000175:diagnosis* / Q000453:epidemiology; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D062606:Tertiary Care Centers / Q000706:statistics & numerical data