Background: The point prevalence of depression and its relationship to poor outcomes among patients with chronic kidney disease (CKD) has not been fully characterized.
Methods: We performed a secondary analysis of a prospective cohort of 374 patients admitted with congestive heart failure between March 1, 1997 and June 30, 1998, to investigate the point prevalence of depression among patients with CKD and its association with mortality. The Beck Depression Inventory (BDI) was administered to all patients. Those who scored 10 or higher were administered the National Institute of Mental Health Diagnostic Interview Schedule (DIS). Logistic regression was used to examine the association between severe CKD, corresponding to a creatinine clearance less than 30 mL/min/72 kg (<0.50 mL/s/72 kg), depression, and mortality at 1 year.
Results: Point prevalences of depressive symptoms by BDI and major depression by DIS were 54.8% and 21.6% if severe CKD was present and 32.8% and 13.0% if severe CKD was absent, respectively. After controlling for important clinical factors, severe CKD was associated with depressive symptoms by BDI (odds ratio, 2.89; 95% confidence interval, 1.39 to 5.99). Both depression by DIS and severe CKD were significant predictors of mortality. The increased mortality risk associated with depression did not decline with decreasing kidney function.
Conclusion: Depression was more prevalent among patients with than without severe CKD and had at least as strong an association with mortality as compared with depression in patients with no or less severe CKD. The point prevalence of depression decreased when the DIS interview was used, perhaps related to the presence of somatic measures on the BDI reflecting uremia. Studies assessing the efficacy of antidepressants among patients with CKD are needed to determine whether, in addition to treating depression, pharmacotherapy impacts mortality.