Hyperparathyroidism may lead to graft loss after kidney transplantation even without hypercalcemia, investigators report.
In a study of 892 kidney transplant recipients, death-censored graft survival after 5 years was significantly lower among patients with hyperparathyroidism and normal serum calcium levels than among patients without hyperparathyroidism: 96.7% vs 99.6%, Manabu Okada, MD, PhD, of the Japanese Red Cross Nagoya Daini Hospital in Nagoya, Aichi, Japan, and colleagues reported in BMC Nephrology.
A multivariate analysis showed that normocalcemic hyperparathyroidism was independently associated with a 1.9-fold increased risk for death-censored graft loss. The investigators confirmed this result in a propensity-score matched analysis. They also observed a pattern of graft loss at higher categories of intact parathyroid hormone (PTH).
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Dr Okada’s team acknowledged that poor graft survival among patients with normocalcemic hyperparathyroidism might have been influenced by low estimated glomerular filtration rate (eGFR) or hypertension. The study lacked data on vitamin D, fibroblast growth factor 23, other bone biomarkers, and kidney stones.
“These results suggest the need for active management of elevated PTH levels after [kidney transplantation], even in the absence of hypercalcemia,” the investigators wrote. “Furthermore, for the prevention of [post-transplant] hyperparathyroidism, active intervention for elevated PTH prior to [kidney transplantation] should be considered.”
They emphasized that treatments should be individualized to minimize hypercalcemia. Parathyroidectomy or medical treatments such as calcimimetics, vitamin D, or bisphosphonates should be prescribed according to underlying conditions, including levels of serum calcium, PTH, parathyroid gland hyperplasia, kidney function, bone loss, and cardiovascular risk profile.
In line with previous research, donor specific antibodies, serum phosphate level, and body mass index were significantly associated with 2.8-, 1.5-, and 1.1-fold increased risks for death-censored graft loss. Each 1 mL/min/1.73 m2 increase in eGFR at 1 year after transplant surgery was significantly associated with a 3% lower risk for graft loss.
Reference
Okada M, Tominaga Y, Sato T, et al. Elevated parathyroid hormone one year after kidney transplantation is an independent risk factor for graft loss even without hypercalcemia. BMC Nephrol. Published online June 17, 2022. 23(1):212. doi:10.1186/s12882-022-02840-5
