Parathyroidectomy as a therapeutic tool for targeting the recommended NKF-K/DOQI ranges for serum calcium, phosphate and parathyroid hormone in dialysis patients.

BACKGROUND

The recommended NKF-K/DOQI'99 ranges for Ca, P and PTH in dialysis seem advisable also for patients previously submitted to parathyroidectomy; however no paper addresses, specifically in this condition, to what extent optimal values are targeted in the short and long term after surgery.

METHODS

We checked serum Ca, P and PTH basally and after 1 month and 1, 3 and 5 years since surgery, in 77 dialysis subjects who received parathyroidectomy in our hospital.

RESULTS

Immediately after surgery all biochemical para- meters dropped, but afterwards Ca showed a tendency to increase progressively in the long term (p <.0006), P increased mostly within one year (p <.01), and PTH increased similarly to Ca (p <.003), but with mean values always in the lower than desired range. The estimated percentage of patients at target during the follow-up was maximal for P (values between 65 and 76%), lower for Ca (zenith of 43% after 1 month but declining down to 14% after 5 years) and minimal for PTH (invariably <10%). Persistence within the ranges (at least on two consecutive checks) was 21% after one month for Ca, with a tendency to reduction; 41% for P, with a tendency to average roughly 30%, and practically zero for PTH. Neither type of surgery (total or subtotal) nor vitamin D therapy were associated with the low values of PTH observed.

CONCLUSIONS

We conclude that parathyroid surgery does not represent an optimal therapeutic tool for targeting the recommended ranges for Ca, P and PTH. In particular, too low PTH values are frequently obtained, whose clinical effects deserve further studies. The possibility of a time dependent risk for recurrence is confirmed.