Impact of post‐kidney transplant parathyroidectomy on allograft function

Abstract

The impact of parathyroidectomy on allograft function in kidney transplant patients is unclear. We conducted a retrospective, observational study of all kidney transplant recipients from 1988 to 2008 who underwent parathyroidectomy for uncontrolled hyperparathyroidism (n=32). Post-parathyroidectomy, changes in estimated glomerular filtration rate (eGFR) and graft loss were recorded. Cross-sectional associations at baseline between eGFR and serum calcium, phosphate, and parathyroid hormone (PTH), and associations between their changes within subjects during the first twomonths post-parathyroidectomy were assessed. Post-parathyroidectomy, the mean eGFR declined from 51.19mL/min/1.73m(2) at parathyroidectomy to 44.78mL/min/1.73m(2) at twomonths (p<0.0001). Subsequently, graft function improved, and by 12months, mean eGFR recovered to 49.76mL/min/1.73m(2) (p=0.035). Decrease in serum PTH was accompanied by a decrease in eGFR (p=0.0127) in the first twomonths post-parathyroidectomy. Patients whose eGFR declined by ≥20% (group 1) in the first twomonths post-parathyroidectomy were distinguished from the patients whose eGFR declined by <20% (group 2). The two groups were similar except that group 1 had a higher baseline mean serum PTH compared with group 2, although not significant (1046.7±1034.2 vs. 476.6±444.9, p=0.14). In group 1, eGFR declined at an average rate of 32% (p<0.0001) during the first month post-parathyroidectomy compared with 7% (p=0.1399) in group 2, and the difference between these two groups was significant (p=0.0003). The graft function recovered in both groups by oneyr. During median follow-up of 66.00±49.45months, 6 (18%) patients lost their graft with a mean time to graft loss from parathyroidectomy of 37.2±21.6months. The causes of graft loss were rejection (n=2), pyelonephritis (n=1) and chronic allograft nephropathy (n=3). No graft loss occurred during the first-year post-surgery. Parathyroidectomy may lead to transient kidney allograft dysfunction with eventual recovery of graft function by 12months post-parathyroidectomy. Higher level of serum PTH pre-parathyoidectomy is associated with a more profound decrease in eGFR post-parathyroidectomy.