Short-term versus long-term effects of depressive symptoms on mortality in patients on dialysis

Abstract

Objective: Depressive symptoms seem to pose a risk factor for mortality among patients on dialysis. It is currently unknown whether the association is only short-lived and whether associations over time depend on specific causes of mortality.

Methods: In a prospective nationwide cohort study, 1528 patients with end-stage renal disease starting on dialysis completed the Mental Health Inventory. Patients were observed up to 5 years or until the end of follow-up in April 2011. Cox regression analyses were used to calculate associations between depressive symptoms and short-term (0-6 months), medium-term (6-24 months), or long-term (24-60 months) cardiovascular and noncardiovascular mortality.

Results: The adjusted hazard ratio (HR) was 1.43 (95% confidence interval [CI] = 1.08-1.88) for cardiovascular mortality and 2.07 (95% CI = 1.62-2.64) for noncardiovascular mortality. Depressive symptoms posed a strong risk factor for noncardiovascular mortality at the short term (HR = 2.82, 95% CI = 1.58-5.05), medium term (HR = 2.08, 95% CI = 1.40-3.09), and long term (HR = 1.84, 95% CI = 1.26-2.69), whereas the association between depressive symptoms and cardiovascular mortality was not observed during the first 6 months of follow-up (HR = 1.03, 95% CI = 0.49-2.15).

Conclusions: Depressive symptoms at the start of dialysis therapy are associated with short-, medium-, and long-term mortality. The cause-specific mortality risk over time may help clinicians to understand multifactorial causes of the association between depressive symptoms and survival.