Assessment of health-related quality of life in patients treated with hemodialysis in Serbia: influence of comorbidity, age, and income

The importance of measuring health-related quality of life (HRQoL) in patients on maintenance hemodialysis (HD) is being increasingly recognized, but few studies, especially from the Balkan region, have addressed this issue. The aims of this study were (i) to evaluate HRQoL in an outpatient university-affiliated dialysis facility in South Serbia; (ii) to determine the effects of age, presence of comorbidity, primary kidney disease, dose of HD, and family income; and (iii) to make comparisons of the HRQoL in Serbian patients on chronic HD with that reported by others previously. The study enrolled 192 patients on HD for more than 3 months. Comorbidity was assessed using the index of coexistent diseases (ICED), including two subindexes: index of disease severity (IDS) and index of physical impairment (IPI). Patient's self-assessment of HRQoL was measured by the 36-item short form health survey questionnaire (SF-36), encompassing eight summary scales and two summary dimensions. Ten of the baseline variables had significant associations with parameters of HRQoL. Fitting these variables in linear regression models resulted in 41.9% variance for physical dimension of HRQoL (physical component summary score PCS]), and 32.5% for mental dimension of HRQoL (mental component summary score MCS]). However, statistically significant effect had only IDS, IPI, and age for PCS, and income of patients for MCS. We found that an increase in IDS score for one unit is associated with a decrease of PCS by 13.2%, and SF-36 score (total quality of life) by 15.2%. The increase of IPI score by one unit decreases PCS by 16.1% and SF-36 score by 17.5%. A 5-year increase in age is associated with a decrease of PCS by 3.1%, and SF-36 score by 3.8%. The monthly income increase of 10 euros per family member increases MCS by 5.2% and SF-36 score by 3.0%. HRQoL in patients on HD was found markedly impaired. Comorbid conditions have negative and statistically significant correlation with parameters of HRQoL, and could explain poor HRQoL to a remarkable extent. Older age and poor income substantially reduce HRQoL in HD patients.