http://repub.eur.nl/res/aut/41750/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/34735/ 2012-01-01T00:00:00Z Background.Early living-donor transplantation improves patient-and graft-survival compared with possible cadaveric renal transplantation (RTx), but the magnitude of the survival gain is unknown. For patients starting renal replacement therapy (RRT), we aimed to quantify the survival benefit of early living-donor transplantation compared with dialysis and possible cadaveric transplantation and to estimate the population benefit from increasing the early transplantation rate. Methods.We used a decision-analytic computer-simulation model, with a lifetime time horizon, simulating patients starting RRT, using data from the Dutch End-Stage Renal Disease Registry and published data. We compared the (quality adjusted) life expectancy (LE) of 'early living-donor RTx' and 'dialysis' (with possible cadaveric RTx if available). Results.LE and quality-adjusted LE benefits of the early living-donor RTx compared with the dialysis strategy for 40-year-old patients ranged from 7.5 to 9.9 life years (LYs) [6.7-8.8 quality-adjusted life years (QALYs)] depending on the primary renal disease. For 70-year-old patients, the benefit was 4.3-6.0 LYs (4.3-6.0 QALYs). Increasing the early transplantation rate from currently 5.8 to 22.2% (the highest in Europe) would increase average LE by 1.2 LYs and total LE for annual incident cases in the Netherlands by >1800 LYs. Conclusions.Efforts to increase early living-donor RTx could potentially substantially increase LE for patients starting RRT, especially in younger patients. http://repub.eur.nl/res/pub/28650/ 2010-05-13T00:00:00Z Purpose. To control for confounding bias from non-random treatment assignment in observational data, both traditional multivariable models and more recently propensity score approaches have been applied. Our aim was to compare a propensity score-stratified model with a traditional multivariable-adjusted model, specifically in estimating survival of hemodialysis (HD) versus peritoneal dialysis (PD) patients. Methods. Using the Dutch End-Stage Renal Disease Registry, we constructed a propensity score, predicting PD assignment from age, gender, primary renal disease, center of dialysis, and year of first renal replacement therapy. We developed two Cox proportional hazards regression models to estimate survival on PD relative to HD, a propensity score-stratified model stratifying on the propensity score and a multivariable-adjusted model, and tested several interaction terms in both models. Results. The propensity score performed well: it showed a reasonable fit, had a good c-statistic, calibrated well and balanced the covariates. The main-effects multivariable-adjusted model and the propensity score-stratified univariable Cox model resulted in similar relative mortality risk estimates of PD compared with HD (0.99 and 0.97, respectively) with fewer significant covariates in the propensity model. After introducing the missing interaction variables for effect modification in both models, the mortality risk estimates for both main effects and interactions remained comparable, but the propensity score model had nearly as many covariates because of the additional interaction variables. Conclusion. Although the propensity score performed well, it did not alter the treatment effect in the outcome model and lost its advantage of parsimony in the presence of effect modification. http://repub.eur.nl/res/pub/35652/ 2007-01-01T00:00:00Z Considerable geographic variation exists in the relative use of hemodialysis (HD) vs peritoneal dialysis (PD). Studies comparing survival between these modalities have yielded conflicting results. Our aim was to compare the survival of Dutch HD and PD patients. We developed Cox regression models using 16 643 patients from the Dutch End-Stage Renal Disease Registry (RENINE) adjusting for age, gender, primary renal disease, center of dialysis, year of start of renal replacement therapy, and included several interaction terms. We assumed definite treatment assignment at day 91 and performed an intention-to-treat analysis, censoring for transplantation. To account for time dependency, we stratified the analysis into three time periods, >3-6, >6-15, and >15 months. For the first period, the mortality hazard ratio (HR) of PD compared with HD patients was 0.26 (95% confidence interval (CI) 0.17-0.41) for 40-year-old non-diabetics, which increased with age and presence of diabetes to 0.95 (95% CI 0.64-1.39) for 70-year-old patients with diabetes as primary renal disease. The HRs of the second period were generally higher. After 15 months, the HR was 0.86 (95% CI 0.74-1.00) for 40-year-old non-diabetics and 1.42 (95% CI 1.23-1.65) for 70-year-old patients with diabetes as primary renal disease. We conclude that the survival advantage for Dutch PD compared with HD patients decreases over time, with age and in the presence of diabetes as primary disease.