Pre-Transplant and Persistent Post-Transplant Hyperparathyroidism and Kidney Transplant Outcomes - A Systematic Review and Meta-analysis

Abstract Background Hyperparathyroidism (HPT) is common in chronic kidney disease and may persist after kidney transplantation, but its prognostic significance remains uncertain because of heterogeneous definitions and variable timing of assessment. Methods We performed a systematic review and meta-analysis of observational studies in adult kidney transplant recipients (KTRs) in accordance with PRISMA 2020 (PROSPERO CRD420261293712). PubMed/MEDLINE and Embase were searched from inception to February 9, 2026. Exposures included pre- and post-transplant PTH/Persistent HPT assessed as categorical or continuous variables. Outcomes were all-cause mortality, overall graft failure, and death-censored graft failure (DCGF). Random-effects models (REML) were applied, with Hartung-Knapp sensitivity analyses; risk of bias was assessed using QUIPS. Results 23 studies were included in the systematic review, and 19 studies (26 266 KTRs) contributed to the meta-analyses (3 pre-transplant studies N = 12 819; 16 post-transplant studies N = 13 447). Pre-transplant HPT was not associated with all-cause mortality (HR 0.80) and showed an association with DCGF in the main analysis (HR 1.42) that lost statistical significance with Hartung-Knapp adjustment. By contrast, categorical Persistent HPT was associated with higher risks of all-cause mortality (HR 1.74), overall graft failure (HR 2.16), and DCGF (HR 1.92), with consistent Hartung-Knapp results. Phenotype-stratified analyses showed a gradient of graft failure risk from normocalcemic HPT (HR 1.66) to hypercalcemic HPT (HR 2.67), with minimal heterogeneity. Continuous PTH analyses showed substantial heterogeneity and were not robust in sensitivity analyses. Conclusions Post-transplant Persistent HPT is a consistent risk marker for mortality and adverse graft outcomes, whereas the prognostic significance of pre-transplant HPT remains to be clarified. Standardized definitions and prospective studies are needed to clarify causality and treatment effects.