Treatment with Cinacalcet Post Kidney Transplant Does Not Confer Clinically Meaningful PTH Suppression Compared with No Treatment

Background: Cinacalcet is a calcimimetic used to treat secondary hyperparathyroidism (SHP) of end-stage kidney disease (ESKD) that fails to achieve adequate parathyroid hormone (PTH) suppression with calcitriol or other vitamin D analogs. However, their role to control persistent PTH after kidney lacks supporting evidence. We hypothesized that the use of calcimimetics provides no meaningful difference in PTH level after kidney transplant when compared with calcitriol or other vitamin D analogs or no therapy at all. Methods: A retrospective chart review was performed searching for adults with a diagnosis of SHP who received a kidney transplant at Ochsner Health between 2018 and 2022. SHP was defined by ICD code. We excluded those with parathyroidectomy, dual organ transplant or missing data. We compared 6-month post-transplant PTH amongst patients being treated with cinacalcet, cinacalcet and calcitriol, calcitriol, or no treatment, by linear regression. Results: 226 patients were included, mean age was 51 (20-78), mean BMI was 30 (19-47), 43% women, and 56% Black. 93% had hypertension, 39% had diabetes. All treatment groups showed a statistically significant decrease in PTH 6 months after transplant, as expected. Mean post-transplant PTH for those on cinacalcet, cinacalcet and calcitriol, calcitriol, and no treatment were 272, 208, 320, and 277 pg/mL, respectively. Adjusting for age, pre-transplant PTH, type of donor, delayed graft function, and dialysis before transplant, we observed no difference in mean PTH after transplant in patients treated with cinacalcet alone compared to the no treatment group (p=0.21); however, we observed a lower mean post-transplant PTH with those treated with calcitriol alone (p=0.0007). Conclusion: Use of cinacalcet after kidney transplant was not associated with a clinically significant difference in PTH suppression when compared to cinacalcet and calcitriol, calcitriol, or no treatment. Our findings suggest that calcimimetics may not be beneficial for the treatment of SHP after kidney transplant.