Table 2 Results of multivariate regression analysis.

	β	SE of β	t Value	p Value
A. Parameters correlating with the initial sural SNAP
BMI	–0.15	0.15	–0.96	0.34
AHI	–0.33	0.15	–2.19	0.034
Age	–0.44	0.13	–3.46	0.001
B. Parameters correlating with the difference between the second and the first sural SNAP
BMI	0.09	0.25	0.13	0.72
AHI	–0.37	0.20	0.37	0.085
Age	–0.43	0.24	–1.83	0.087
SNAP	0.25	0.18	–1.82	0.17
Compl	0.56	0.17	3.25	0.005

AHI, Apnoea–Hypopnea Index; β, partial correlation coefficient; BMI, body mass index; Compl, treatment compliance; SNAP, pretreatment sensory nerve action potential.