Does depression in old age increase only cardiovascular mortality? The Leiden 85-plus study.
Vinkers DJ, Stek ML, Gussekloo J, van der Mast RC and Westendorp RGJ;
Commented by , 22 Oct 2004
Objective
It is known that depression increases cardiovascular mortality. This study sought to investigate prospectively the effect of depression on cardiovascular and non-cardiovascular mortality in great old age.
Method
Subjects were drawn from the wider Leiden 85-plus Study. All over 85 year olds in Leiden with an MMSE > 18 were invited to participate. Depressive symptoms were annually assessed with the 15-item Geriatric Depression Scale (GDS-15), a score of 4 out of 15 was chosen as the cut-off.
All subjects were followed up for three years. If they died in this period, the cause of death was obtained from the civic registry and interviewing the treating physician (general practitioner or nursing home physician) with a standardised questionnaire.
Cause of death was divided by ICD-10 category into cardiovascular mortality (myocardial infarction, stroke, other cardiovascular) or non-cardiovascular mortality (all other causes).
Mortality for each group was calculated per 1,000 observed person-years at risk for person-years with depression and without depression. Data was also collected for gender, smoking, alcohol consumption and chronic disease.
Results
At baseline, 119/500 subjects scored > 4 on the GDS. During follow-up, 1,654 person-years were observed (mean per person 3.2 years); 116 subjects died (23 % of subjects). The all cause mortality was 57 per thousand person-years with depression, 108 per thousand person-years without depression. All cause mortality risk was increased two-fold in depressed subjects, after adjusting for gender, smoking, alcohol consumption and chronic disease. Without this correction, cardiovascular as well as non-cardiovascular mortality were significantly1.95-fold and 1.75-fold increased in participants with depression.
Dr Seymour's comments
Depression is an illness that kills. It is well established in the literature that all cause mortality and cardiovascular mortality is increased in depressed older people, this prospective community population study suggests that mortality from other causes is increased too, at least in the oldest old.
How does depression in old age increase mortality? In essence, this is not known. Possible cardiovascular mechanisms include low heart rate variability, platelet activation, elevated catecholemines and hypothalemic-pituitary-adrenal axis disruption. Other postulated non-cardiovascular influences in depression include suppression of the immune system.
In this study, mortality was increased in depressed people with good cognitive function, independent in activities of daily living, and without chronic diseases, i.e., the excess mortality could not be explained by co-morbidity and frailty.
Furthermore, antidepressant medication was almost non-existent in this study population, so treatment effects of depression could not be implicated in the excess mortality.
There has been a lot of recent adverse publicity for antidepressant medications and the pharmaceutical industry in the mass media recently. Clinicians need to be aware however, that untreated depression carries a two-fold risk of all-cause mortality in older people, which far outweighs any theoretical risks of harm from antidepressants.