Switching from an intravenous (IV) vitamin D analog to oral calcitriol results in no worse outcomes in patients with secondary hyperparathyroidism (SHPT) on maintenance hemodialysis (HD), new study results published in the Clinical Journal of the American Society of Nephrology confirm.
In a study of patients receiving maintenance HD, investigators led by Len Usvyat, MD, of Fresenius Medical Care North American in Waltham, Massachusetts, identified IV vitamin D analog users (doxercalciferol or paricalcitol) who switched to oral calcitriol administered in their dialysis centers. The team then matched the 2280 patients who switched to 2280 patients continuing on an IV vitamin D analog by sex, race (60% black), ethnicity, vascular access, end-stage renal disease network, age, dialysis vintage, body mass index, comorbidities, and mean postdialysis systolic blood pressure, and calcium, albumin, phosphate, and intact parathyroid hormone (iPTH) levels.
At 4 to 6 months after the switch, mean calcium (9.05 vs 9.21 mg/dL) and phosphate levels (5.12 vs 5.24 mg/dL) in the oral calcitriol group were significantly lower than in the IV vitamin D group. However, iPTH levels were significantly higher in the oral calcitriol group (497 vs 427 pg/dL). At baseline, iPTH values were 300 to 400 pg/mL.
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By 12 months, the same proportion (45% vs 45%) of both groups had all 3 bone mineral parameters within target ranges (calcium less than 10 mg/dL, phosphate 3.0-5.5 mg/dL, and iPTH 150-600 pg/mL).
More importantly, hospital admissions, length of stay, and survival did not differ significantly between groups over the 12-month study. Cinacalcet use did not affect these results. Over time, however, doses of cinacalcet, IV vitamin D, and oral calcitriol increased.
In the United States, IV vitamin D analogs have been used by default in SHPT patients after early studies suggested they led to fewer episodes of hypercalcemia and hyperphosphatemia compared with oral calcitriol. The new study results corroborate more recent, but small, unmatched studies showing no clinical differences between IV vitamin D and oral calcitriol.
“Although more of the oral calcitriol users had iPTH values that exceeded a threshold of 600 pg/mL (as recommended by Kidney Disease Improving Global Outcomes), outcomes between the two groups did not appear to differ,” Dr Usvyat’s team wrote.
Disclosure: This clinical trial was supported by Fresenius Medical Care. Please see the original reference for a full list of authors’ disclosures.
Reference
Thadhani RI, Rosen S, Ofsthun NJ, et al. Conversion from intravenous vitamin D analogs to oral calcitriol in patients receiving maintenance hemodialysis [published online February 28, 2020]. Clin J Am Soc Nephrol. doi: 10.2215/CJN.07960719
