An Association between Residual Renal Function and Depression Symptoms in Haemodialysis Patients

Background: The loss of residual renal function (RRF) and subsequent urine volume among haemodialysis (HD) patients may influence affect. Although RRF has been associated with improved patient outcome, its relationship with depression symptomatology is unknown. Methods: 106 HD patients completed the Beck Depression Inventory (BDI). The BDI is a depression symptom screening tool, with a score of 16 indicating possible clinical depression. Clinical parameters, including RRF (urea clearance, KRU [ml/min]) and interdialytic urine volume, were averaged over the 3-month pre-assessment including the month of the BDI assessment. Results: BDI scores correlated negatively with KRU and interdialytic urine volume. Patients with a KRU <1 had significantly higher BDI scores compared to those with a KRU 1. In logistic regression, KRU significantly predicted a BDI score 16, after controlling for a range of clinical parameters including urea, dialysis vintage and treatment time. A history of depressive illness was the only other predictive factor. Conclusion: We have demonstrated an association between RRF and depression symptoms in HD patients. The perception of loss associated with low RRF and urine volume may increase depressive vulnerability. Longitudinal assessment is required in order to validate this finding and to determine causality.