Table 2.

Comparison of relevant factors between patients with normal and low serum calcium and iPTH concentrations 1 day after total thyroidectomy (n = 546).

		Serum calcium			iPTH
		Normal	Low		Normal	Low
Variable	Total	(n = 343)	(n = 203)	P-value	(n = 340)	(n = 206)	P-value
Sex				0.960			0.787
Female	388	244	144		243	145
Male	158	99	59		97	61
Age, years		51.2 ± 13.6	50.0 ± 12.3	0.307	50.6 ± 9.9	51.3 ± 9.5	0.454
Preoperative diagnosis				0.771			0.709
Thyroid nodular goiter	123	78	45		75	48
Thyroid follicular tumor	83	53	30		49	34
Thyroid carcinoma	340	212	128		216	124
Surgical procedure				0.088			0.266
Total thyroidectomy plus  central dissection	316	189	127		190	126
Total thyroidectomy	230	154	76		150	80
Preoperative laboratory data
Calcium, mmol/L		2.23 ± 0.09	2.22 ± 0.09	0.952	2.27 ± 0.08	2.26 ± 0.09	0.888
25-hydroxyvitamin D3, ng/mL		21.82 ± 8.38	20.94 ± 7.71	0.221	20.47 ± 8.38	19.19 ± 7.96	0.079
Magnesium, mmol/L		0.87 ± 0.07	0.89 ± 0.30	0.224	0.88 ± 0.31	0.84 ± 0.25	0.070
Phosphate, mmol/L		1.16 ± 0.18	1.13 ± 0.22	0.096	1.16 ± 0.16	1.13 ± 0.26	0.114
Alkaline phosphatase, pg/mL		73.4 ± 23.7	71.2 ± 21.6	0.256	62.1 ± 23.1	65.1 ± 18.7	0.111
TSH, mIU/L		1.87 ± 1.01	1.91 ± 0.95	0.653	1.95 ± 1.04	2.09 ± 1.04	0.147
iPTH, pg/mL		38.8 ± 11.9	39.4 ± 11.1	0.586	37.34 ± 15.5	39.07 ± 10.4	0.119
24 hours postoperatively
iPTH, pg/mL		24.37 ± 10.6	21.23 ± 10.6	0.001	26.72 ± 8.45	9.07 ± 3.38	<0.001
Calcium, mmol/L		2.16 ± 0.05	1.95 ± 0.05	<0.001	2.10 ± 0.01	1.89 ± 0.12	<0.001

Data are expressed as number or as mean ± standard deviation.

iPTH, intact parathyroid hormone; TSH, thyroid-stimulating hormone.

A P value of <0.05 was considered statistically significant.