Methods: We performed an English literature search using Medline and PsycLIT. Studies were included if they reported SF-36 scale scores of hemodialysis (HD), peritoneal dialysis (PD) patients and/or renal transplant (RTx) recipients, if they had included at least 10 patients per treatment group and reported mean age and prevalence of diabetes mellitus as co-morbidity. We extracted demographic, clinical and quality-of-life data. Using random-effects models, we calculated means and 95% confidence intervals for age, proportion with diabetes, and SF-36 scale scores both unadjusted and adjusted for age and diabetes in random-effects meta-regression models; we considered α=0.05 to indicate statistical significance.

Results: We found 35 studies, reporting SF-36 scores of 27,853 patients. Mean age was 56.9 years for HD patients and 53.6 years for PD patients, which was significantly higher than the age of RTx recipients (45.3 years). Prevalence of diabetes was 21% among HD, 16% among PD, and 7% among RTx patients. In general, unadjusted SF-36 scores were higher for RTx compared to dialysis patients. HD and PD patients‘ SF-36 scores were not statistically significantly different. After adjustment, the significance of the differences of both dialysis groups compared to RTx recipients disappeared for the Physical Functioning scale (unadjusted: HD 52.0, PD 53.2, RTx 74.8 vs adjusted HD 63.7, PD 58.3, RTx 66.7). In addition, the significance of the differences between HD and RTx patients disappeared on three scales: the Role Physical (unadjusted HD: 41.8, PD 32.5, RTx 66.3 vs adjusted: HD 49.8, PD 35.1, RTx 57.2), the Bodily Pain (unadjusted: HD 60.9, PD 65.5, RTx 74.0 vs adjusted: HD 65.0, PD 67.6, RTx 72.0) and the Vitality scales (unadjusted: HD 45.2, PD 44.9, RTx 58.6 vs adjusted: HD 48.1, PD 45.2, RTx 52.5). The non-significantly lower score of PD as compared to HD patients on the Role Physical scale became statistically significant.

Conclusions: Differences in age and diabetes as a co-morbidity among hemodialysis, peritoneal dialysis, and renal transplantation patients partly explained the differences in SF-36 scores among these treatment groups. Differences on mainly the physical aspects of quality of life were not statistically different among these groups after adjustment for age and diabetes.