Predictors of postoperative hypocalcemia occurring after a total thyroidectomy: results of prospective multicenter study

Eismontas, Vitalijus; Slepavicius, Algirdas; Janusonis, Vinsas; Zeromskas, Paulius; Beisa, Virgilijus; Strupas, Kestutis; Dambrauskas, Zilvinas; Gulbinas, Antanas; Martinkenas, Arvydas

doi:10.1186/s12893-018-0387-2

Table 2 Patient characteristics

From: Predictors of postoperative hypocalcemia occurring after a total thyroidectomy: results of prospective multicenter study

Variables^a	Hypocalcemia		p value
Variables^a	Yes	No	p value
Gender, n (%)	257	143
Female	221 (63.3)	128 (36.7)	χ2 = 1.02, df = 1, p = 0.351
Male	36 (70.6)	15 (29.4)	χ2 = 1.02, df = 1, p = 0.351
Age in years, mean (SD)	57.8 (13.2)	56.0 (13.8)	0.207
Weight, kg., mean (SD)	79.0 (15.2)	79.5 (16.8)	0.721
Thyrotoxicosis before surgery, n (%)
No	170 (66.1)	107 (74.8)	χ2 = 4.10, df = 2, p = 0.129
<10 years	76 (29.6)	29 (20.3)
≥10 years	11 (4.3)	7 (4.9)
Graves’ disease, n (%)
No	241 (93.8)	138 (96.5)	χ2 = 1.38, df = 1, p = 0.350
Yes	16 (6.2)	5 (3.5)	χ2 = 1.38, df = 1, p = 0.350
Recurrent goiter, n (%)
No	254 (98.8)	143 (100)	χ2 = 1.68, df = 1, p = 0.556
Yes	3 (1.2)	0	χ2 = 1.68, df = 1, p = 0.556
Retrosternal goiter, n (%)
No	250 (97.3)	143 (100)	χ2 = 3.96, df = 1, p = 0.053
Yes	7 (2.7)	0	χ2 = 3.96, df = 1, p = 0.053
Bone mass density, T level, n (%)
No	394 (98.5)	394 (98.5)	χ2 = 0.54, df = 1, p = 0.671
Yes	6 (1.5)	6 (1.5)	χ2 = 0.54, df = 1, p = 0.671
Preoperative calcium, mmol/L, mean (SD)^b	2.35 (0.09)	2.39 (0.11)	< 0.001
MD (IQR)	2.35 (0.11)	2.39 (0.12)	< 0.001
Preoperative ionized calcium, mmol/L, mean (SD)^b	1.04 (0.07)	1.08 (0.10)	< 0.001
MD (IQR)	1.03 (0.07)	1.07 (0.09)	< 0.001
Preoperative PTH, ng/L (pg/mL), mean (SD)^b	57.86 (22.18)	57.43 (22.50)	0.855
MD (IQR)	54.17 (26.38)	53.65 (26.05)	0.855
Preoperative 25-hydroxyvitamin D, nmol/L, mean (SD)^c	44.22 (22.97)	47.16 (20.17)	0.053
MD (IQR)	40.35 (30.47)	46.40 (26.69)	0.053
Preoperative TSH, mlU/L, mean (SD)^c	1.12 (1.33)	0.96 (0.97)	0.355
MD (IQR)	0.80 (1.20)	0.70 (1.17)	0.355
Preoperative FT3, pmol/L, mean (SD)^b	4.85 (2.73)	4.90 (1.50)	0.854
MD (IQR)	4.60 (0.83)	4.71 (0.93)	0.854
Preoperative FT4, pmol/L, mean (SD)^b	13.53 (2.47)	13.67 (3.05)	0.626
MD (IQR)	13.45 (2.92)	13.40 (2.36)	0.626
Thyroidectomy without lymphadenectomy, n (%)
No	48 (18.7)	18 (12.6)	χ2 = 2.47, df = 1, p = 0.124
Yes	209 (81.3)	125 (87.4)	χ2 = 2.47, df = 1, p = 0.124
Thyroidectomy with one sided central lymphadenectomy, n (%)
No	216 (84.0)	128 (89.5)	χ2 = 2.28, df = 1, p = 0.175
Yes	41 (16.0)	15 (10.5)	χ2 = 2.28, df = 1, p = 0.175
Thyroidectomy with central lymphadenectomy on both sides, n (%)
No	250 (97.3)	140 (97.9)	χ2 = 0.15, df = 1, p = 1.000
Yes	7 (2.7)	3 (2.1)	χ2 = 0.15, df = 1, p = 1.000
Number of observed parathyroid glands, n (%)
0	2 (0.8)	0	χ2 = 35.23, df = 4, p < 0.001
1	3 (1.2)	5 (3.5)
2	76 (29.6)^**	21 (14.7)^**
3	142 (55.3)	66 (46.2)
4	34 (13.2)^***	51 (36.7)^***
Upper branch of left inferior thyroid artery, n (%)
Non-ligation	231 (89.9)	132 (92.3)	χ2 = 0.64, df = 1, p = 0.475
Ligation	26 (10.1)	11 (7.7)	χ2 = 0.64, df = 1, p = 0.475
Lower branch of left inferior thyroid artery, n (%)
Non-ligation	232 (90.3)	134 (93.7)	χ2 = 1.39, df = 1, p = 0.267
Ligation	25 (9.7)	9 (6.3)	χ2 = 1.39, df = 1, p = 0.267
Trunk of left inferior thyroid artery, n (%)
Non-ligation	46 (17.9)	44 (30.8)	χ2 = 8.73, df = 1, p = 0.003
Ligation	211 (82.1)	99 (69.2)	χ2 = 8.73, df = 1, p = 0.003
Upper branch of right inferior thyroid artery, n (%)
Non-ligation	232 (90.3)	126 (88.1)	χ2 = 0.46, df = 1, p = 0.501
Ligation	25 (9.7)	17 (11.9)	χ2 = 0.46, df = 1, p = 0.501
Lower branch of right inferior thyroid artery, n (%)
Non-ligation	231 (89.9)	135 (94.4)	χ2 = 2.42, df = 1, p = 0.137
Ligation	26 (10.1)	8 (5.6)	χ2 = 2.42, df = 1, p = 0.137
Trunk of right inferior thyroid artery, n (%)
Non-ligation	44 (17.1)	47 (32.9)	χ2 = 12.96, df = 1, p < 0.001
Ligation	213 (82.9)	96 (67.1)	χ2 = 12.96, df = 1, p < 0.001
Number of darkened parathyroid glands at the end of surgery, n (%)
0	194 (75.5)	111 (77.6)	χ2 = 3.64, df = 3, p = 0.303
1	54 (21.0)	26 (18.2)
2	7 (2.7)	2 (1.4)
3	2 (0.8)	4 (2.8)
Parathyroid gland hematoma, n (%)
No	244 (94.9)	135 (94.4)	χ2 = 0.05, df = 1, p = 0.818
Yes	13 (5.1)	8 (5.6)	χ2 = 0.05, df = 1, p = 0.818
Number of autotransplanted parathyroid glands, n (%)
0	205 (79.8)^*	127 (88.8)^*	χ2 = 6.32, df = 3, p = 0.097
1	40 (15.6)	14 (9.8)
2	9 (3.5)	2 (1.4)
3	3 (1.2)	0
Adenomatous nodules, n (%)
No	218 (84.8)	116 (81.1)	χ2 = 0.92, df = 1, p = 0.399
Yes	39 (15.2)	27 (18.9)	χ2 = 0.92, df = 1, p = 0.399
Colloidal nodules, n (%)
No	81 (31.5)	49 (34.3)	χ2 = 0.32, df = 1, p = 0.579
Yes	176 (68.5)	94 (65.7)	χ2 = 0.32, df = 1, p = 0.579
Papillary carcinoma, n (%)
No	203 (79.0)	142 (99.3)	χ2 = 0.46, df = 1, p = 0.518
Yes	54 (21.0)	26 (18.2)	χ2 = 0.46, df = 1, p = 0.518
Follicular carcinoma, n (%)
No	257 (100)	399 (99.3)	χ2 = 1.80, df = 1, p = 0.358
Yes	0	1 (0.7)	χ2 = 1.80, df = 1, p = 0.358
Medullary carcinoma, n (%)
No	254 (98.8)	143 (100)	χ2 = 1.68, df = 1, p = 0.556
Yes	3 (1.2)	0	χ2 = 1.68, df = 1, p = 0.556
Anaplastic carcinoma, n (%)
No	257 (100)	143 (100)
Autoimmune thyroiditis, n (%)
No	234 (91.1)	129 (90.2)	χ2 = 0.08, df = 1, p = 0.857
Yes	23 (8.9)	14 (9.8)	χ2 = 0.08, df = 1, p = 0.857
Calcium day one, mmol/L, mean (SD)	2.05 (0.12)	2.24 (0.11)	< 0.001
MD (IQR)	2.05 (0.16)	2.25 (0.13)	< 0.001
Ionized calcium day one, mmol/L, mean (SD)	0.96 (0.07)	1.06 (0.07)	< 0.001
MD (IQR)	0.96 (0.08)	1.05 (0.09)	< 0.001
PTH, ng/L (pg/mL), mean (SD)	24.42 (18.27)	39.97 (17.50)	< 0.001
MD (IQR)	21.47 (29.24)	38.09 (20.86)	< 0.001
Calcium day two, mmol/L, mean (SD)	1.96 (0.12)	2.20 (0.08)	< 0.001
MD (IQR)	1.99 (0.18)	2.19 (0.11)	< 0.001
Ionized calcium day two, mmol/L, mean (SD)	0.94 (0.07)	1.06 (0.07)	< 0.001
MD (IQR)	0.94 (0.09)	1.05 (0.08)	< 0.001
Revision for bleeding, n (%)
No	254 (98.8)	142 (99.3)	χ2 = 0.20, df = 1, p = 1.000
Yes	3 (1.2)	1 (0.7)	χ2 = 0.20, df = 1, p = 1.000
Wound infection, n (%)
No	257 (100)	143 (100)
Wound hematoma, n (%)
No	249 (96.9)	140 (97.9)	χ2 = 0.35, df = 1, p = 0.753
Yes	8 (3.1)	3 (2.1)	χ2 = 0.35, df = 1, p = 0.753
Bleeding during surgery, n (%)
No	256 (99.6)	143 (100)	χ2 = 0.56, df = 1, p = 1.000
Yes	1 (0.4)	0	χ2 = 0.56, df = 1, p = 1.000
Clinical voice hoarseness, n (%)
No	245 (95.3)	139 (97.2)	χ2 = 0.84, df = 1, p = 0.434
Yes	12 (4.7)	4 (2.8)	χ2 = 0.84, df = 1, p = 0.434
Recurrent laryngeal nerve paralysis on one side, ORL, n (%)
No	252 (98.1)	140 (97.9)	χ2 = 0.84, df = 1, p = 0.434
Yes	5 (1.9)	3 (2.1)	χ2 = 0.84, df = 1, p = 0.434
Recurrent laryngeal nerve paralysis on both sides, ORL, n (%)
No	257 (100)	143 (100)
Clinical manifestation of hypocalcemia, n (%)
None	197 (76.7)	143 (100)	χ2 = 39.27, df = 2, p < 0.001
Day 1	14 (3.5)	0
Day 2	46 (17.9)	0
Hypocalcemia without clinical manifestation, n (%)
No	60 (23.3)	143 (100)	χ2 = 215.99, df = 1, p < 0.001
Yes	197 (76.7)	0	χ2 = 215.99, df = 1, p < 0.001
Hypocalcemia - Chvostekʼs symptoms, n (%)
No	243 (94.6)	143 (100)	χ2 = 8.07, df = 1, p = 0.004
Yes	14 (5.4)	0	χ2 = 8.07, df = 1, p = 0.004
Hypocalcemia - Trousseau’s symptoms, n (%)
No	249 (96.9)	143 (100)	χ2 = 4.54, df = 1, p = 0.033
Yes	8 (2.0)	0	χ2 = 4.54, df = 1, p = 0.033
Hypocalcemia - Numbness of fingers, n (%)
No	199 (77.4)	143 (100)	χ2 = 37.75, df = 1, p < 0.001
Yes	58 (22.6)	0	χ2 = 37.75, df = 1, p < 0.001
Treatment commenced in hospital with calcium and vitamin D preparations after surgery, n (%)
None	23 (8.9)	139 (97.2)	χ2 = 297.04, df = 4, p < 0.001
Day 1	15 (5.8)	0)
Day 2	33 (12.8)	0
Day 3	5 (1.9)	0
On discharge	181 (70.3)	4 (2.8)

^aContinuous variables are presented as means and standard deviations (SD) & medians and interquartile ranges (IQR); categorical variables are presented as n (%). ^bStudent t test; ^cMann-Whitney U test. ^* p < 0.05, z test, ^** p < 0.01, ^*** p < 0.001. PTH Parathyroid hormone, ORL otorhinolaryngologist

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