Conversion to Oral Calcitriol Feasible in SHPT
An academic hemodialysis center realized cost savings from vitamin D receptor activator therapy after converting to oral calcitriol -- without negative impact on SHPT control.
Current management of secondary hyperparathyroidism (SHPT) involves calcimimetics, vitamin D receptor activators (VDRA), and phosphate binders. Now researchers at the University of California Irvine report that converting from the VDRA paricalcitol to calcitriol appears safe, effective, and economical.
Intravenous (IV) paricalcitol has been widely used. Few studies have explored the risks and benefits of returning to oral calcitriol since the introduction of calcimimetics. So a team led by Madeleine Pahl, MD, reviewed the medical records of patients who made the transition. In 2013–2014, their academic dialysis center changed 74 hemodialysis patients with SHPT from routine use of IV paricalcitol to pulse, oral calcitriol 3 times a week (0.25 mcg = 1 mcg paricalcitol) due to pharmacy purchasing preferences. An additional 17 patients newly started oral calcitriol. Nephrologists could adjust patients' dosages as needed.
Oral calcitriol appeared well-tolerated with only 1 patient reporting gastrointestinal discomfort, according to results published online ahead of print in the Journal of Renal Nutrition.
Use of other drugs changed somewhat after VDRA conversion. Among phosphate binders, sevelamer use increased from 44.1% to 52.7%, whereas calcium acetate use decreased from 66.7% to 50.5%. Cinacalcet use fell slightly from 39.7% to 38.4%.
Five months after conversion, patients' average serum calcium, phosphorus, and intact parathyroid hormone levels remained unchanged. Patients continue to meet targets set by the Kidney Disease Outcome Quality Initiative (KDOQI) guidelines. Importantly, the investigators observed no increase in cardiovascular events over the short-term, defined as acute coronary syndrome, acute decompensated heart failure, cerebrovascular accident, and peripheral arterial disease.
Cost savings of converting to oral calcitriol were estimated to be $584 per person per year, although the researchers could not determine concomitant cost increases for other treatments, if any. The cost savings reflect the US market in the setting of Medicare bundled payments; drug prices vary in other countries.
Among the limitations, the investigators acknowledged that the study reflects the experience of a small number of patients at a single dialysis center over a short follow up period.