Systematic Review Of Effect Of Phosphate Binders On Coronary Vascular Calcification in End Stage Renal Disease
Srikanth Raayasa, M. D., Phyllis August, M. D., MPH.
Department of Medicine and Lang Research Center, New York Hospital Queens, Flushing, NY
Background: The presence and extent of vascular calcification is a significant predictor of cardiovascular morbidity and mortality in patients with End Stage Renal Disease (ESRD). The non-calcium based phosphate binder, Sevelamer is equally efficacious in phosphorus level reduction as the cheaper calcium based binders. However, Sevelamer is hypothesized to be more effective in reducing the cardiac mortality in End stage renal disease patients compared to calcium-based binders. We reviewed the available literature to assess the effect of Sevelamer compared to calcium based phosphate binders on coronary artery calcium score as a surrogate marker of cardiac mortality.
Methods: We searched MEDLINE, EMBASE, COCHRANE database of systematic reviews, CENTRAL and TOXNET to identify relevant studies and papers on Sevelamer versus calcium-based binders and mortality. Two independent reviewers reviewed the data. Inclusion criteria were: randomized controlled trials (RCTs), studying adults with ESRD and comparing Sevelamer to any calcium based binders with respect to Coronary Artery Calcium scores (CAC). Studies that were non-randomised, prospective studies and those which studied pre-dialysis patients were excluded. Two reviewers independently extracted data from each article using a standardized form. Quality was assessed using JADAD score and study with JADAD score of above 2 were only included in the final analysis.
Results: The search yielded a total of 30 articles published between 1990 and December 2008. Application of the inclusion criteria yielded four randomized trials comparing the effect of Sevelamer with calcium based phosphate binders on the progression of coronary artery calcium score over a period of 12 months.
Study (First author) / Number of subjects randomized / Mean progression in CAC scores in Sevelamer vs Ca based binders / P value / Conclusions
1.Chertow et al / 200 / -46±692 vs. 151±471 / p=0.04 / Sevelamer less likely to cause CAC progression
2.Block et al / 127 / 87± 324 vs. 169±311 / p=0.056 / Significant survival benefit with Sevelamer
3.Qunibi et al / 203 / 1116±1569 vs. 1297±1487 / p=0.3 / Similar progression of CAC in both groups
4.Barreto et al / 101/ 139±240 vs. 182±333 / p=0.526 / Similar progression in CAC in both groups
Conclusions: There is no conclusive evidence that there is reduced CAC score progression or reduced mortality in patients taking Sevelamer compared to calcium based phosphate binders. Further randomized controlled trials with larger number of patients and longer follow up are needed answer this question.