Topical cutaneous application of carbon dioxide via a hydrogel for improved fracture repair: results of phase I clinical safety trial

Table 9 Sub-group analysis regarding the influence of smoking on the increase in blood flow by the CO₂ therapy in the fractured limb of patients

Measuring site	Treatment day	Smoking status	n	Mean (range) [95%CI]	p-value (1)	p-value (2)
Fracture level	1	Non-smoker	5	1.377 (1.153–1.618) [1.117–1.637]	0.063	0.65
		Current smoker	12	1.429 (0.970–2.846) [1.109–1.749]	< 0.001
		Previous smoker	2	1.420 (1.366–1.473) [0.739–2.100]	0.50
	14	Non-smoker	5	1.656 (1.156–2.057) [1.202–2.110]	0.063	0.055
		Current smoker	12	1.899 (1.184–3.152) [1.500–2.299]	< 0.001
		Previous smoker	2	1.220 (1.158–1.281) [0.436–2.003]	0.50
	28	Non-smoker	5	1.692 (1.306–2.844) [0.884–2.500]	0.063	0.12
		Current smoker	12	2.455 (1.236–5.100) [1.664–3.247]	< 0.001
		Previous smoker	2	1.343 (1.277–1.408) [0.515–2.170]	0.50
5 cm from the fracture level	1	Non-smoker	5	1.457 (1.164–2.000) [1.062–1.852]	0.063	0.93
		Current smoker	12	1.503 (1.010–2.000) [1.337–1.669]	< 0.001
		Previous smoker	2	1.382 (1.060–1.705) [−2.71–5.478]	0.50
	14	Non-smoker	5	1.719 (1.206–2.611) [1.064–2.374]	0.063	0.036
		Current smoker	12	2.015 (1.453–2.660) [1.751–2.278]	< 0.001
		Previous smoker	2	1.241 (1.168–1.314) [0.313–2.168]	0.50
	28	Non-smoker	5	1.842 (1.215–3.018) [0.942–2.742]	0.063	0.036
		Current smoker	12	2.200 (1.488–3.431) [1.868–2.531]	< 0.001
		Previous smoker	2	1.170 (1.038–1.302) [−.504–2.843]	0.50

Blood flow increase is demonstrated by the ratio of blood flow measured after 20 min of CO₂ therapy to that at pre-treatment. n: number of patients. p-value (1): calculated using Wilcoxon signed rank test with a null hypothesis that the population mean of the blood flow ratio is 1. p-value (2): calculated using Kruskal–Wallis test to compare the three groups (Non-smoker versus current smoker versus previous smoker)

ISSN: 1471-2474