The contribution of depression to mortality among elderly with self-reported hypertension: analysis using a national representative longitudinal survey.

OBJECTIVE: Previous research has suggested that hypertension and depression are two of the important causes of mortality among the elderly. This study aims to test the contribution of depression to mortality among elderly with self-reported hypertension.
METHODS: This research used data from the Survey of Health and Living Status of the Middle Age and Elderly (SHLS) conducted by the Bureau of Health Promotion, Department of Health in Taiwan. The 1989, 1996, 1999, 2003, and 2007 waves were used. In total, 3736 respondents aged 60 or above were analyzed. Participants were grouped by status of hypertension and depression. The contribution of depression to mortality among elderly with self-reported hypertension was estimated using Cox proportional hazard model. Analyses were separated into younger elderly individuals (<70 years) and older elderly individuals (≥ 70 years).
RESULTS: In the full model, the hazard ratios for mortality for the groups of not hypertensive/depressed, hypertensive/not depressed, and hypertensive/depressed were 1.12 [95% confidence interval (CI) 0.98-1.28], 1.32 (95% CI 1.19-1.46), and 1.54 (95% CI 1.29-1.83), respectively, compared with the reference group of not hypertensive/not depressed. The pattern remained the similar after separating the participants into the two age groups. However, much higher hazard ratios were observed for the older cohort.
CONCLUSION: Depression contributes significantly to the hypertension-mortality relationship for the elderly. For the elderly, hypertension should be tackled along with depression in order to reduce the mortality associated with hypertension.