Predictors of recurrent hyperparathyroidism after total parathyroidectomy in chronic renal failure.

BACKGROUND/AIMS: Recurrent hyperparathyroidism (HPT) after total parathyroidectomy (TPTX) in chronic renal failure appears more common than might be anticipated. METHODS: To study its predictors, we reviewed all 20 cases of TPTX performed at our hospital in a 10-year period. RESULTS: During follow-up (median 46.8 months (range 9.3-120.3)), 15 patients had measurable PTH levels (>10 pg/ml), 7 had levels above the normal range (recurrent HPT), and 3 had PTH levels >300 pg/ml (severe recurrent HPT). Total follow-up post-TPTX was equal in those who developed recurrent HPT and others, but those with recurrent HPT had spent longer on dialysis post-TPTX (61.9 +/- 34.9 vs. 21.8 +/- 12.0 months; p = 0.001). Patients with recurrent HPT required less vitamin D supplementation during the 10 days post-TPTX (p = 0.025). Log [maximal PTH post-TPTX] correlated with duration of dialysis dependency post-TPTX (r = 0.591, p = 0.006), lowest serum calcium level during the first 30 days post-TPTX (r = 0.449, p = 0.047), and mean serum calcium during the first 30 days post-TPTX (r = 0.546, p = 0.013). Mean log [maximal PTH post-TPTX] was significantly lower in patients with ectopic calcification (p = 0.047). In multiple regression analysis, duration of dialysis post-TPTX and lowest serum calcium level during the first 30 days post-TPTX were the only independent predictors of log [maximal PTH post-TPTX]. CONCLUSION: Recurrent HPT is common following TPTX and predicted by duration of dialysis dependency post-TPTX, a measure of overall exposure to the uraemic stimulus to parathyroid hyperplasia, and the degree of early hypocalcaemia, possibly reflecting the adequacy of operative parathyroid ablation.