A Prospective Study of Vitamin D Supplement in Thyroidectomy Patients Based on Relative Decline of Parathyroid Hormone

Abstract

Background: In postthyroidectomy patients, hypocalcemia is the most common complication to prolong hospital stay and decrease patients’ satisfaction. Based on current evidence, it is recommended to supply vitamin D to patients with high risk of developing hypocalcemia. However, how to stratify the risk of patients remains challenging.Aim: We conducted a prospective study to evaluate the effect of vitamin D supplement (calcitriol) on high-risk hypocalcemia patients based on relative decline of parathyroid hormone (RDP).Method: RDP was calculated by the difference between preoperative and postoperative first-day PTH divided by preoperative PTH and presented as percentage. Patients who underwent total thyroidectomy in addition to bilateral central compartment dissection were enrolled prospectively and were divided into two cohorts: Cohort I: patients with RDP ≤70% and Cohort II: patients with RDP >70%. Patients in Cohort I were then randomly assigned to Group A or B, and patients in Cohort II were randomly assigned to Group C or D. All groups received oral calcium, and patients in Groups B and D also received calcitriol. All patients were followed for one year. In the study, standard procedure dictates that only oral calcium is given to patients whose RDP ≤70% and that oral calcium and calcitriol are given to patients whose RDP >70%. Therefore, Cohort I Group A and Cohort II Group D are controls in this study.Results: The incidence of clinical hypocalcemia in Groups A and D (the controls) was 11.0% (10/91), and 17.6% (16/91) required additional intravenous calcium. Of note, no patients developed permanent hypocalcemia. Furthermore, calcitriol supplement did not have significant impact on clinical outcomes between Group A and B in Cohort I. By contrast, calcitriol supplement distinctly improved clinical outcome by comparing Groups C and D (Cohort II), as marked by clinical hypocalcemia, need of requiring intravenous calcium, and long-termed decreased levels of PTH.Conclusion: Supplying calcitriol based on RDP cutoff of 70% may be a wise practice in thyroidectomy patients, and RDP 70% may be a useful predictor to stratify high-risk patients.

Role of vitamin D supplementation in modifying outcomes after surgery: a systematic review of randomised controlled trials

“…Only 4 of the 14 studies20 23 25 26 were multicentre, and the majority had no published protocol. All studies randomised patients into two arms (vitamin D supplementation vs control), although Hao et al 27 additionally divided patients into two cohorts by the relative decline of parathyroid hormone prior to randomisation; these were treated as two separate cohorts for analysis. The included studies focused on a wide range of patient conditions, including open heart surgery, cancer operations and both elective and emergency orthopaedic conditions requiring surgery (online supplemental table 2).…”

“…Comparisons of length of hospital stay were reported for eight studies 19 21 23 24 26–28 30. Of these, Hao et al 27 reported outcomes for two subgroups, defined by the relative decline of parathyroid hormone (≤70% and >70%), which were treated separately for analysis, giving a total of nine cohorts (n=1051 patients).…”

“…Comparisons of length of hospital stay were reported for eight studies 19 21 23 24 26–28 30. Of these, Hao et al 27 reported outcomes for two subgroups, defined by the relative decline of parathyroid hormone (≤70% and >70%), which were treated separately for analysis, giving a total of nine cohorts (n=1051 patients). Two studies reported significantly shorter lengths of hospital stay in the vitamin D arm, namely Hajimohammadebrahim-Ketabforoush et al 28 (median: 5 vs 8 days, p=0.008) and Naguib et al 30.…”

“…However, this was in contrast to the remaining studies, which generally reported similar averages in the two arms, generally with a negligible trend towards longer lengths of hospital stay in the vitamin D supplementation arm. Five studies19 21 24 27 30 assumed a normal distribution when summarising the length of hospital stay and ICU stay24 30 data, reporting these as means with SDs. However, in many cases, these statistics indicated that the underlying data likely followed a skewed distribution.…”

“…In order to elevate serum 25(OH)-D, patients would need daily supplementation for at least 3 months prior to an operation. The earliest preoperative dosing time was 5 weeks,22 with other studies dosing in the postoperative period,18 20 25 27 29 which is unlikely to have an impact on serum 25(OH)-D levels. Single high-dose bolus supplementation, as performed in some of the included trials,19 23 28 may well raise serum 25(OH)-D levels rapidly but will also trigger catabolic feedback enzymes that negate the likely beneficial effects of vitamin D 4 5.…”