Background: Assessing health-related quality of life (HRQOL) can provide information on the types and degrees of burdens that afflict patients with chronic medical conditions, including end-stage renal disease (ESRD). Several studies have shown important international differences among ESRD patients treated with hemodialysis, but no studies have compared these patients' HRQOL. Our goal was to document international differences in HRQOL among dialysis patients and to identify possible explanations of those differences.
Methods: We examined data from the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective, observational, international study of hemodialysis patients. We performed a cross-sectional analysis of DOPPS data from the United States, five countries in Europe (France, Germany, Italy, Spain, and the United Kingdom), and Japan. Linear mixed models were used to analyze differences in HRQOL, using the KDQOL-SFTM. Norm-based scores were used to minimize cultural response bias. Linear regression analysis was used to adjust for confounding factors. Other variables included demographic variables, comorbidities, primary cause of ESRD, complications of ESRD and treatment, and socioeconomic status.
Results: In all generic HRQOL subscales, patients on all three continents had much lower scores than their respective population norm values. Patients in the United States had the highest scores on the mental health subscale and the highest mental component summary scores. Japanese patients reported better physical functioning than did patients in the United States or Europe, but they also reported the greatest burden of kidney disease. Overall, these differences remained even after adjusting for possible confounders.
Conclusion: On all three continents, ESRD and hemodialysis profoundly affect HRQOL. In the United States, the effects on mental health are smaller than in other countries. Japanese hemodialysis patients perceived that their kidney disease imposes a greater burden, but their physical functioning was significantly higher. Different distributions of socioeconomic factors and major comorbid conditions could explain little of this difference in physical functioning. Other possible factors, such as quality of dialysis and related health care, deserve careful study.