Health-related quality of life and depression in dialysis patients: associations with current smoking

Abstract

Objective: The study explored health-related quality of life (HRQoL) and depression in a culturally homogeneous dialysis patient population. Furthermore, the associations between HRQoL and depression with current smoking were elaborated.

Material and methods: In a cross-sectional study of 301 dialysis patients from 10 dialysis centres in Norway, HRQoL was evaluated with the Kidney Disease and Quality of Life Short Form, version 1.3. Physical component summary scores (PCS) and mental component summary scores (MCS) were computed. Depression was assessed using the Beck Depression Inventory (BDI), and Cognitive Depression Index (CDI) was calculated. Depression was defined as a BDI score greater than 14.

Results: HRQoL was poorer in dialysis patients compared with population norms. Depression was prevalent (33.2%), and differed significantly between smokers and non-smokers (52.8 vs 26.4%, p < 0.001). MCS was significantly reduced in smokers compared with non-smokers (44.1 +/- 12.2 vs 48.7 +/- 10.3, p < 0.001), but there was no difference in PCS (35.7 +/- 10.2 vs 37.1 +/- 10.4, not significant). Current smoking was independently associated with higher BDI score (p = 0.039), as well as with higher CDI score (p = 0.005) and worse score on MCS (p = 0.002), after adjustments for multiple covariates.

Conclusions: HRQoL is lower in Norwegian dialysis patients than in the general population, and depression is prevalent. The study suggests that poor perceived mental aspects of HRQoL and depression are associated with current smoking in dialysis patients, but a causal relationship remains to be shown.