Comparison of neurohormone and callus volume formation in long bone fractures associated with or without traumatic brain injury

Table 1 Biochemical marker parathyroid hormone over time in patients with and without traumatic brain injury

PTH (pg/mL)	Group	n	mean ± SD	Statistic (test type)	P value	Significance
7 days	Without TBI	25	7.2 ±3.0	t = -9.05 (t-test)	< 0.0001	Significant
	With TBI	16	42.0 ± 15.2
6 weeks	Without TBI	25	15.8 ± 5.5	U = 175 (Mann-Whitney)	0.51	Non-significant
	With TBI	16	305.2 ± 500.3
12 weeks	Without TBI	25	8.9 ± 4.0	t = -5.25 (t-test)	< 0.0001	Significant
	With TBI	16	38.2 ± 22.1

PTH: Parathyroid hormone; TBI: Traumatic brain injury.

Table 2 Biochemical marker growth hormone over time in patients with and without traumatic brain injury

GH (pg/mL)	Group	n	mean ± SD	Statistic (test type)	P value	Significance
7 days	Without TBI	25	0.08 ± 0.06	t = -7.59 (t-test)	< 0.0001	Significant
	With TBI	16	1.6 ± 0.8
6 weeks	Without TBI	25	0.55 ± 0.22	t = -4.79 (t-test)	< 0.0001	Significant
	With TBI	16	8.1 ± 6.3
12 weeks	Without TBI	25	0.22 ± 0.09	t = -7.55 (t-test)	< 0.0001	Significant
	With TBI	16	2.3 ± 1.1

GH: Growth hormone; TBI: Traumatic brain injury.

Table 3 Biochemical marker interleukin-6 over time in patients with and without traumatic brain injury

IL-6 (pg/mL)	Group	n	mean ± SD	Statistic (test type)	P value	Significance
7 days	Without TBI	25	22.3 ± 8.2	t = -10.52 (t-test)	< 0.0001	Significant
	With TBI	16	130.2 ± 40.5
6 weeks	Without TBI	25	78.2 ± 20.1	t = -8.80 (t-test)	< 0.0001	Significant
	With TBI	16	410.5 ± 150.2
12 weeks	Without TBI	25	25.6 ± 10.3	t = -11.00 (t-test)	< 0.0001	Significant
	With TBI	16	220.5 ± 70.4

IL-6: Interleukin-6; TBI: Traumatic brain injury.

Table 4 Callus volume over time in patients with and without traumatic brain injury

Time point	Group	n	mean ± SD (cm3)	Statistic (test type)	P value	Significance
6 weeks post-injury	Without TBI	25	12.3 ± 28.0	t = -3.10 (t-test)	0.0058	Significant
	With TBI	16	62.1 ± 60.2
12 weeks post-injury	Without TBI	25	22.1 ± 38.5	t = -3.20 (t-test)	0.0049	Significant
	With TBI	16	98.2 ± 90.1

TBI: Traumatic brain injury.

Table 5 Correlation analysis of neurohormonal parameters in bone repair

Variable pair	Correlation coefficient (r)	P value	Interpretation
GH-PTH	0.55	0.001	Significant positive correlation
GH-IL-6	0.47	0.005	Significant positive correlation
PTH-IL-6	0.60	0.0008	Significant positive correlation

GH: Growth hormone; PTH: Parathyroid hormone; IL-6: Interleukin-6.

Table 6 Multivariate regression: Predictors of callus volume at 6 weeks

Variable	Coefficient	P value	Significant
GH 7 days	0.38	0.002	Yes
PTH 7 days	0.31	0.011	Yes
IL-6 7 days	0.41	0.001	Yes
TBI status	0.49	0.0005	Yes
Age	-0.02	0.21	No
Sex	0.06	0.33	No

GH: Growth hormone; PTH: Parathyroid hormone; IL-6: Interleukin-6; TBI: Traumatic brain injury.