Table 2.

Comparison of postoperative PTH and serum calcium in CNs and control groups

Results	CN group	Control group	χ²(t/Z) value	P value
Day one after surgery
PTH (n, %)
≥ 15 pg/mL	177/326 (54.3%)	31/51 (60.8%)	χ² = 0.751	0.386
< 15 pg/mL	149/326 (45.7%)	20/51 (39.2%)	χ² = 0.751	0.386
∆PTH(%, $\bar{x} \pm s$ ,)	(57.2 ± 28.6)%	(55.7 ± 27.8)%	Z = − 0.372	0.710
Serum calcium (n, %)
≥ 2.1 mmol/L	142/325 (43.7%)	19/50 (38.0%)	χ² = 0.573	0.449
< 2.1 mmol/L	183/325 (56.3%)	31/50 (62.0%)	χ² = 0.573	0.449
1 month after surgery
PTH (n, %)
≥ 15 pg/mL	251/271 (92.6%)	43/45 (95.6%)	χ² = 0.160	0.689
< 15 pg/mL	20/271 (7.4%)	2/45 (4.4%)	χ² = 0.160	0.689
Serum calcium (n, %)
≥ 2.1 mmol/L	275/312 (88.1%)	32/40 (80.0%)	χ² = 2.107	0.147
< 2.1 mmol/L	37/312 (11.9%)	8/40 (20.0%)	χ² = 2.107	0.147
Half year after surgery
PTH (n, %)
≥ 15 pg/mL	300/311 (96.5%)	49/50 (98.0%)	χ² = 0.019	0.890
< 15 pg/mL	11/311 (3.5%)	1/50 (2.0%)	χ² = 0.019	0.890
Serum calcium (n, %)
≥ 2.1 mmol/L	291/314 (92.7%)	42/47 (89.4%)	χ² = 0.250	0.617
< 2.1 mmol/L	23/314 (7.3%)	5/47 (10.6%)	χ² = 0.250	0.617
Unintentional parathyroid removal (n, %)
No	291/334 (87.1%)	45/52 (86.5%)	χ² = 0.014	0.907
Yes	43/334 (12.9%)	7/52 (13.5%)	χ² = 0.014	0.907

CNs carbon nanoparticles, PTH parathyroid hormone, ∆PTH = (PTH before surgery–PTH of day 1 after surgery)/PTH before surgery × 100%