Higher serum total 25-hydroxyvitamin D (25D) levels than guidelines recommend may be needed to reduce progression of secondary hyperparathyroidism (SHPT) in patients with stage 3-4 chronic kidney disease (CKD), according to investigators presenting at the European Renal Association-European Dialysis and Transplant Association’s 56th Congress in Budapest, Hungary.

In 2 trials of extended-release calcifediol (ERC), investigators randomly assigned 429 patients with intact parathyroid hormone (iPTH) levels of 85 to less than 500 pg/mL and vitamin D insufficiency (serum 25D of 10 to less than 30 ng/mL) to receive ERC (30 or 60 mcg/day) or placebo for 26 weeks. They ranked patients by quintiles of serum total 25D values following treatment.

More than a third of patients in the lower 25D quintiles experienced SHPT progression, defined as an increase in iPTH of 10% or more from baseline, Stephen Strugnell, PhD, of OPKO Health in Miami, and colleagues reported. In quintiles 1 to 5, 36.6%, 33.8%, 9.7%, 2.8%, and 4.2% of patients progressed, respectively, regardless of their CKD stage. Significant iPTH suppression only occurred when mean serum total 25D had increased to at least 51 ng/mL (quintiles 3 and higher). Dr Strugnell’s team observed no new safety signals with treatment to higher total 25D levels up to a mean 92.5 ng/mL.

Current guidelines recommend vitamin D repletion to 30 ng/mL in moderate CKD.

“Pooled data from two identical prospective RCTs with ERC support aggressive vitamin D repletion therapy to attenuate SHPT progression and a revised serum 25D target of at least 51 ng/mL in stage 3-4 CKD,” Dr Strugnell and the team stated in their study abstract.

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Reference

Strugnell S, Sprague S, Akhtar A, et al. Attenuation of secondary hyperparathyroidism progression in stage 3-4 CKD requires a serum total 25-hydroxyvitamin D target above 50 ng/mL. Presented at the European Renal Association-European Dialysis and Transplant Association 56th Congress in Budapest, Hungary. Abstract FP444.