Recurrence of secondary hyper¬parathyroidism in dialysis patients after parathyroidectomy

Abstract

Parathyroidectomy is an effective therapy for refractory secondary hyperparathyroidism (sHPT). Continued dialysis represents risk for recurrent sHPT. The aim of this study was to estimate the proportion of recurrence and de¬termine its predictors.
Methods: We conducted a retrospective observational study of 92 adults in chronic dialysis, who underwent their first parathyroi¬dectomy in this center between 2006 and 2015. We considered persistence of sHPT if PTH was > 300 pg/ml during the first postope¬rative semester, and recurrence if it was > 500 pg/ml afterwards.
Results: Age 43.6+-12 y/o, 50% female, 4.6 years on dialysis, median preoperative PTH 1636 pg/ml (IQR 1226-2098). Subtotal parathyroidectomy (sPTX) was performed in 39, Total with autotransplantation (TA-PTX) in 53 patients. Persistence of sHPT occurred in 16 patients; relapse in 30 out of 76 with adequate initially response (39.5%; 95CI 28,5-50,5). Median time to recurrence: 4.7 y. Recurring patients had higher preoperative calcemia (9.9 vs 9.3 mg/dl; adj OR 2.79) and lower postoperative elevation of ALP (333 vs 436 UI/ml; adj OR 0.99). Recurrence presented more frequently in TA-PTX (48.9%; adj OR 4.66) than sPTX (25.8%).
Conclusions: Time on dialysis with ina¬dequate metabolic control remains the most important risk factor for sHPT recurrence. Hig¬her preoperative levels of calcemia, related to sHPT severity, are associated with recurrence. Lower elevations of ALP during postoperative period in recurring patients are an interesting finding. We hypothesize that patients with less significant postoperative mineralization may have chronically higher levels of phosphate¬mia, stimulating parathyroid glands. Fewer re¬currence in sPTX is associated to a bias in the procedure selection.