Depression, non-fatal stroke and all-cause mortality in old age: A prospective cohort study of primary care patients

Background Depression is a risk factor for stroke and mortality but whether this also holds into old age is uncertain. We therefore studied the association of depression with the risk for non-fatal stroke and all-cause mortality in very old age. Methods A representative sample of 3085 primary care patients aged ≥75 years were serially assessed during a 6-year follow-up. The relation between depression (Geriatric Depression Scale >6, n=261) and relevant covariates including vascular risk factors and disease, functional and mild cognitive impairment and ApoE genotype on primary care givers information of incident stroke (n=209) and mortality (n=647) were assessed by Cox regression and by competing risk regressions. Results Depression was not independently associated with incident stroke in fully adjusted models that treated death as the competing event (subdistribution hazard ratio=0.80, 95% confidence interval=0.47 to 1.36). The risk associated with depression was similar for men and women, and for age groups 75–79, 80–84 and ≥85 years. In contrast, depression increased all-cause mortality rates, even after adjusting for a range of confounders (hazard ratio=1.31, 95% confidence interval=1.03 to 1.67). Limitations We have no information on past depressive episodes and cause of death. Conclusions In contrast to reports in younger populations, depression does not appear to increase stroke risk among the old and very old, but continuous to be a risk factor for all-cause mortality.