Association Between Pre-Kidney Transplantation Elevated Parathyroid Hormone and Posttransplantation Graft Loss

Before kidney transplantation (KT), most patients have an elevated parathyroid hormone (PTH). However, the impact of PTH on post-KT mortality and graft loss is unclear. We quantified the association between PTH levels measured at transplantation and adverse post-KT outcomes.

We leveraged a prospective longitudinal cohort of 1,136 KT recipients from a single tertiary care center between December 2008 and February 2020. Pre-KT PTH levels were abstracted retrospectively. Adjusted multivariable Cox proportional hazards models were used to estimate the association between pre-KT PTH levels and mortality and death-censored graft loss (DCGL).

Of 1,136 recipients, pre-KT PTH levels were 300 pg/mL or less in 62.3% and more than 600 pg/mL in 12.5%. Compared with those with a pre-KT PTH 300 pg/mL or less, patients with a pre-KT PTH more than 600 pg/mL were more likely to be Black (51.4% vs 34.6%) and have a longer dialysis vintage (4.8 vs 1.7 years, p < 0.001). Those with a pre-KT PTH more than 600 pg/mL had a higher 10-year cumulative incidence of DCGL than those with PTH 300 pg/mL or less (31.7% vs 15.4%, p < 0.001). After adjusting for confounders, pre-KT PTH more than 600 pg/mL was associated with a 1.76-fold increased risk of DCGL (95% CI 1.16 to 2.65). The magnitude of this association differed by race (p interaction = 0.011) and by treatment (p interaction = 0.018). Among non-Black patients, a PTH more than 600 pg/mL was associated with a 3.21-fold increased risk of DCGL compared with those with PTH 300 pg/mL or less (95% CI 1.77 to 5.81). Among untreated patients, those with PTH more than 600 pg/mL had a 2.54-fold increase in DCGL (95% CI 1.44 to 4.47). No association between pre-KT PTH and mortality risk was observed.

PTH more than 600 pg/mL before KT increased the risk of DCGL by 76%, demonstrating the importance of treating PTH before KT to prevent graft loss in a contemporary era with the introduction and widespread availability of medical therapy.