Effects of Paricalcitol on Renal Secondary Hyperparathyroidism and Proteinuria in Dogs With Chronic Kidney Disease

Renal secondary hyperparathyroidism (RHPT) is an inevitable consequence of chronic kidney disease (CKD). Paricalcitol might safely attenuate RHPT and proteinuria.

Paricalcitol decreases parathyroid hormone (PTH) and proteinuria in dogs with CKD.

Thirteen dogs with naturally acquired CKD.

Placebo-controlled clinical trial. Dogs were randomly allocated to receive a placebo or paricalcitol (14 ng/kg/day) in a crossover design of 2, 12-week arms. Dogs were evaluated every 3 weeks. Associations between treatment, visit, and the outcome variables were assessed using generalized estimating equations.

PTH decreased by 22% (95% CI, 7%-35%, p = 0.006) in the paricalcitol-treated dogs and increased by 18% (95% CI, 2%-37%, p = 0.022) in the placebo-treated dogs with each visit. FGF-23 at 12 weeks increased compared with baseline in the paricalcitol-treated (mean 6941 pg/mL, 95% CI, 1781-20 057 vs. 489 pg/mL, 95% CI, 188-1272, p < 0.001, respectively), but not in the placebo-treated dogs (696 pg/mL, 95% CI, 316-1531 vs. 955 pg/mL, 95% CI, 308-2963, p = 0.529). Urine protein-to-creatinine ratio at 12 weeks increased compared with baseline in the placebo-treated (0.8, 95% CI, 0.3-1.3 vs. 0.5, 95% CI, 0.2-0.9, p = 0.04, respectively), but not in the paricalcitol-treated dogs (0.6, 95% CI, 0.3-0.9 vs. 1.0, 95% CI, 0.1-1.8, p = 0.35). Ionized calcium was unchanged between baseline and 12 weeks in the paricalcitol- and placebo-treated groups (1.3 mmol/L, 95% CI, 1.29-1.35 and 1.34, 95% CI, 1.27-1.40 vs. 1.30, 95% CI, 1.25-1.35, p = 0.12 and 1.28, 95% CI, 1.24-1.32, p = 0.034, respectively). However, 7/13 dogs developed mild hypercalcemia. Adverse effects were not reported by the owners.

Paricalcitol attenuated RHPT and stabilized renal proteinuria in dogs with CKD.