The CKD-MBD track at the recent ERA-EDTA 2017 Congress featured numerous sessions, focusing on a broad range of topics. In this congress review article we focus on presentations regarding phosphate binders and active vitamin D therapy.
Phosphate binders: Factors influencing prescription choice
The much-anticipated 2017 KDIGO guidelines update continues to recommend restricted use of calcium-based binders. But what factors other than binder calcium contents could influence the choice of hyperphosphatemia treatment? Two oral symposia presentations attempted to shed some light on the answer to this question.
Prof Floege presented a systematic review of recent phosphate binder data looking, not only at efficacy, but also pill burden, pleiotropic affects, accumulation and cost. The comparatively low pill burdens required with lanthanum carbonate and sucroferric oxyhydroxide were highlighted and Dr Floege suggested that this could factor into patient preference, particularly in older patients with dementia. Dr Floege also suggested that treatment patterns could be adjusted according to the age of the patient – preventing vascular calcification could take on increased importance with younger CKD patients who will likely have greater life expectancy.
In the oral session ‘Iron – the bright and the dark side’ Professor Ketteler provided a comparison of ferric citrate (FC) and sucroferric oxyhydroxide (SO) with regards to changes in iron parameters. Use of FC resulted in sustained increases in serum ferritin and TSAT, despite reductions in ESA and IV iron use, which could lead to cost savings. However, this was achieved with a high pill burden of 6 pills/day, and iron levels must be considered as abnormally high ferritin levels were seen in trials, a fact noted by Prof Floege. By contrast, SO use results in only modest increases in serum ferritin and TSAT levels and has a lower pill burden of 3 pills/day.
However, the continuing challenge of demonstrating therapeutic benefits in terms of hard outcomes in dialysis patients was highlighted once again in an analysis of the COSMOS observational study, featured in the late breaking trials session. In this analysis, presented by Dr Jose Fernandez-Martin, calcium-free phosphate binders alone, or in combination with VDRAs and/or cinacalcet, did not significantly lower the relative risk of all-cause death versus calcium-containing phosphate binders.
Continuing uncertainty regarding active Vitamin D
ERA-EDTA 2017 presentations on Vitamin D also reflected the 2017 KDIGO guidelines update, with sessions discussing the limited data showing clinical benefits of active Vitamin D therapy.
A presentation in the late-breaking trials session reported results of the Japanese J-DAVID study which tested the hypothesis that active vitamin D treatment (oral alfacalcidol) would reduce the risk of cardiovascular events in haemodialysis patients without apparent secondary hyperparathyroidism (SHPT). However, no benefits were found for the primary outcome of composite of fatal and nonfatal cardiovascular events (myocardial infarction, heart failure requiring hospitalization, stroke, aortic dissection/rupture, amputation of lower limb due to ischemia, cardiac sudden death, coronary revascularization, and leg artery revascularization).
By contrast, data from the observational COSMOS study did suggest that vitamin D receptor activators (VDRAs) and/or cinacalcet might lower the risk of all-cause mortality. However, the presenter acknowledged the study’s caveats during the Q&A session, particularly regarding the propensity score matching: “when we have different population, countries, percentages of centres receiving vitamin D, it is very difficult to get two comparable groups”.
- 2017 KDIGO CKD-MBD guideline update
- Phosphate binders in chronic kidney disease: a systematic review of recent data. Jürgen Floege. ERA-EDTA 2017 Congress.
- Fe-based phosphate binders – a role in iron supplementation or a dead end? Markus Ketteler. Symposium presentation – ERA-EDTA 2017 Congress
- [LB03] Effect of calcium free phosphate-binding agents or calcium-containing phosphate binding agents alone or combined with vitamin d receptor activators (VDRAs) and/or cinacalcet on survival. Jose L. Fernandez-Martin et al. ERA-EDTA 2017 Congress.
- [LB05] Active vitamin D in the prevention of cardiovascular events in haemodialysis patients: the Japan Dialysis Active Vitamin D (J-DAVID) trial. Tetsuo Shoji et al. ERA-EDTA 2017 Congress
- COSMOS: PTH lowering drugs and parathyroidectomy. Impact and outcomes. Jose Luis Gorriz. Symposium presentation – ERA-EDTA 2017 Congress