Usefulness of a single-item measure of depression to predict mortality: the GAZEL prospective cohort study.

backgroundIt remains unknown whether short measures of depression perform as well as long measures in predicting adverse outcomes such as mortality. The present study aims to examine the predictive value of a single-item measure of depression for mortality.

methodsA total of 14,185 participants of the GAZEL cohort completed the 20-item Center-for-Epidemiologic-Studies-Depression (CES-D) scale in 1996. One of these items (I felt depressed) was used as a single-item measure of depression. All-cause mortality data were available until 30 September 2009, a mean follow-up period of 12.7 years with a total of 650 deaths.

resultsIn Cox regression model adjusted for baseline socio-demographic characteristics, a one-unit increase in the single-item score (range 0-3) was associated with a 25% higher risk of all-cause mortality (95% CI: 13-37%, P<0.001). Further adjustment for health-related behaviours and physical chronic diseases reduced this risk by 36% and 8%, respectively. After adjustment for all these variables, every one-unit increase in the single-item score predicted a 15% increased risk of death (95% CI: 5-27%, P<0.01). There is also an evidence of a dose-reponse relationship between reponse scores on the single-item measure of depression and mortality.

conclusionThis study shows that a single-item measure of depression is associated with an increased risk of death. Given its simplicity and ease of administration, a very simple single-item measure of depression might be useful for identifying middle-aged adults at risk for elevated depressive symptoms in large epidemiological studies and clinical settings.