Patients on dialysis who switched from calcium-based phosphate binders to sucroferric oxyhydroxide or sevelamer for 1 year experienced significantly reduced serum fibroblast growth factor 23 (FGF-23) levels, a new study finds.
In a post hoc analysis of a phase 3 trial, Markus Ketteler, MD, of Klinikum Coburg and KfH-Dialysis Center in Coburg, Germany, and collaborators pooled results from 549 patients randomly assigned 2:1 to sucroferric oxyhydroxide (1 to 3 g daily) or sevelamer (2.4 to 14.4 g) daily for 24 weeks, followed by a 28-week extension. Two-thirds switched from a calcium-based binder. A previous analysis of the study showed that sucroferric oxyhydroxide and sevelamer similarly reduced serum phosphorus levels.
According to results published in Nephrology Dialysis Transplantation, treatment with the non-calcium binders for 1 year was associated with a significant 30% reduction in serum phosphorus. Median intact FGF-23 significantly fell by 64%.
Intact parathyroid hormone levels initially decreased, then rebounded (patients with secondary hyperparathyroidism were excluded from the study). Serum calcium stayed relatively stable. The bone formation markers bone-specific alkaline phosphatase and osteocalcin increased.
The drop in FGF-23 could not be explained entirely by the fall in phosphorus, according to the investigators. A lack of calcium loading (from calcium-based binders) may have contributed to this decline.
These potentially beneficial changes in parameters of chronic kidney disease-mineral bone disease, notably FGF-23, might reduce risk of cardiovascular morbidity and mortality, Dr Ketteler and his colleagues stated. FGF-23 has been linked with left ventricular hypertrophy, vascular calcification, impaired immune response, inflammation, infection, and mortality.
Ketteler M, Sprague SM, Covic AC, et al. Effects of sucroferric oxyhydroxide and sevelamer carbonate on chronic kidney disease–mineral bone disorder parameters in dialysis patients. Nephrol Dial Transplant 2018;1–8. doi: 10.1093/ndt/gfy127