MO815: Cinacalcet Does not Prevent Severe Hypocalcemia After Parathyroidectomy in Dialysis-Dependent Patients
Authors: Kislyy Pavel , Parshina Ekaterina , Zulkarnaev Aleksei , Tolkach Alexey 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Surgical treatment of secondary hyperparathyroidism (SHPT) is often followed by the rapid development of hypocalcemia, which is also known as hungry bone syndrome. We aimed to evaluate if preoperative use of cinacalcet may help to prevent severe hypocalcemia after parathyroidectomy (PTx) for SHPT in dialysis-dependent patients during the early postoperative period.

METHOD
The retrospective analysis included 616 patients who underwent PTx (either subtotal or total PTx with autotransplantation of parathyroid tissue) for SHPT between 2011 and 2019 in the single tertiary care center of endocrine surgery. Data on severe hypocalcemia development were available for 559 of the patients, 172 of them received cinacalcet before surgery. The median age of the patients was 49 (IQR 40–56) years and the median dialysis duration was 94 (IQR 56–142) months. Preoperative parathyroid hormone level was 153 pmol/L (IQR 105–223), total serum Ca was 2.44 mmol/L (IQR 2.24–2.61) and alkaline phosphatase was 283 IU/l (IQR 157–645). Severe postoperative hypocalcemia was defined as a serum ionized Ca level &lt;0.9 mmol/L on the second or third day post-PTx. We also assessed need for intravenous (IV) calcium supplementation and the duration of in-hospital stay (≤7 days or &gt;7 days) as surrogate markers of hungry bone syndrome severity.

RESULTS
Among patients treated with cinacalcet, 55.8% (n = 96) received 30 mg/day, 33.1% (n = 57)received 60 mg/day, 10.5% (n = 18) received 90 mg/day and 0.6% (n = 1) received 120 mg/day.
Prevalence of severe hypocalcemia was less in patients who received 90 or more mg of cinacalcet a day, although this difference did not reach statistical significance (P = .1038) (Figure 1A). Use of cinacalcet (yes/no) was not associated with the risk of severe postoperative hypocalcemia: RR = 1.047 [95% confidence interval (95% CI) 0.946–1.146], OR = 1.229 (95% CI 0.801–1.886), P = .3837.
A total of 54% of the patients were administered with IV calcium. Preoperative use of cinacalcet did not reduce the risk of IV calcium supplementation need: RR = 0.93 (95% CI 0.79–1.09), OR = 0.86 (95% CI 0.61–1.21); P = .3749. Among patients supplemented with IV calcium, medians of total Ca amount did not differ between those who received pre-PTx cinacalcet and those who did not: 6 (IQR 3–15) g versus 6 (IQR 4–10) g, respectively, P = .3981.
Patients who received 60 mg of cinacalcet a day or more were more likely to require higher amounts of total IV Ca (Figure 1B), but this was not statistically significant [RR = 1.4 (95% CI 0.83–2.4); P = .2138].
In terms of length of hospital stay, we did not find differences between patients received 30, 60 and ≥ 90 mg of cinacalcet a day (P = .1285) (Figure 1C). Use of cinacalcet was not associated with prolonged (&gt;7 days) in-hospital stay: RR = 0.863 (95% CI 0.708–1.04), OR = 0.765 (95% CI 0.546–1.081); P = .1417.

CONCLUSION
We found no evidence of a protective effect of preoperative cinacalcet use, neither on the prevalence nor on the severity of hypocalcemia development after PTx for SHPT in dialysis patients.