Predictive value of postoperative day 1 parathyroid hormone levels for early and late hypocalcaemia after thyroidectomy

Abstract

Purpose Early parathyroid hormone (PTH) levels after total thyroidectomy can predict patients at low risk of hypocalcaemia who can be discharged early without calcium supplementation. For centres without facility to perform early PTH levels, PTH levels sent on the first postoperative day (POD1) may be an alternative. However, there is less data regarding optimal cut-off PTH levels for POD1 discharge. Methods Retrospective review of prospective database of thyroid operations between September 2009 and February 2020 at tertiary referral centre. Main outcome measure was symptomatic hypocalcaemia. Results Five hundred seventy patients undergoing total (521) or completion thyroidectomy with POD1 PTH levels available were included. Among patients with POD1 PTH levels ≥ 20 pg/ml and POD1 calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia was 1% (3/300), and need for intravenous calcium 0.3% (1/300). For POD1 PTH levels 15–19 pg/ml and POD1 calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia and need for intravenous calcium was 5.4% (3/55). For PTH levels 10–14 pg/ml and calcium ≥ 2.0 mmol/l, the incidence of symptomatic hypocalcaemia and need for intravenous calcium was 11.7% (7/60). The risk of permanent hypoparathyroidism was < 1% for POD1 PTH levels ≥ 15 pg/ml; 5.4% for levels 10–14 pg/ml; and 19.8% for levels < 10 pg/ml. Conclusions POD1 PTH levels ≥ 15 pg/ml along with calcium ≥ 2.0 mmol/l are associated with low risk of symptomatic hypocalcaemia, and represent a safe criterion for discharge of most patients without calcium supplementation. For certain patient groups, a higher threshold of 20 pg/ml could be considered.

Management of Postthyroidectomy Hypoparathyroidism and Its Effect on Hypocalcemia‐Related Complications: A Meta‐Analysis

“…A total of 1743 articles were screened (Figure 1) and 237 full‐text articles were assessed for eligibility. After careful selection of the articles, 66 studies were eligible for the final synthesis and were included in this review 10,14,23,24,27‐88 …”

Complications, Symptoms, Presurgical Predictors in Patients With Chronic Hypoparathyroidism: A Systematic Review

“…Screening identified 1619 abstracts of which 521 proved duplicates, leaving 1098 abstracts for review, of which 118 proved potentially eligible. Of these, 17 articles including 18 studies proved eligible ( 95‐111 ) (Fig. S2).…”

“…In Part I, eligible studies identified 170 complications and symptoms derived from 93 studies in 18,973 patients with chronic hypoparathyroidism. Of these, nine complications and symptoms were reported in three or more studies and occurred more often in patients with hypoparathyroidism than in individuals (96,98,103,109) 12-24 hours postoperative 12 (67) (95,97,(99)(100)(101)(102)104,105,107,108,110,111) Threshold Absolute value, pg/mL (pmol/L) ≤10 (1.05) 12 (66) (95,96,98,(100)(101)(102)104,107,(109)(110)(111) 10-15 (1.05-1.58) 4 ( 22) (99,103,105,108) Change in value >50% 1 (6) (97) <50% 0 Combination Absolute <9.3 pg/mL (0.98 pmol/L) and change of >86% 1 (6) (106) Timing of determination of chronic hypoparathyroidism after surgery 3 months (95,99,102,(104)(105)(106)(107)109) Timing of determination of chronic hypoparathyroidism 6 months 6 (67) (95,99,…”

“…Part II: Predicting values of early parathyroid hormone and calcium levels with the development of chronic hypoparathyroidism in patients following total thyroidectomy Screening identified 1619 abstracts of which 521 proved duplicates, leaving 1098 abstracts for review, of which 118 proved potentially eligible. Of these, 17 articles including 18 studies proved eligible (95)(96)(97)(98)(99)(100)(101)(102)(103)(104)(105)(106)(107)(108)(109)(110)(111) (Fig. S2).…”

“…The 18 studies (10 retrospective, (95,96,(100)(101)(102)104,105,107,110,111) and eight prospective, (96)(97)(98)(99)103,106,108,109) ) included 4325 patients, most of whom were women (n = 3457, 80%). Studies varied in their inclusion of malignant disease as an indication for surgery; autotransplantation of parathyroid glands during surgery; consideration of both PTH and calcium as predictors; their definition of chronic hypoparathyroidism; and the prevalence of chronic hypoparathyroidism.…”