Table 6. Multivariate linear regression analysis evaluating the time-dependent effect of surgical treatment on AHI changes, adjusted for clinical covariates (n=74)

Variable	Coefficient (B)	SE	t-value	p-value	95% CI
Constant	–13.04	10.08	–1.29	0.200	–33.16 to 7.08
Surgical treatment (+)	–19.84	6.52	–3.04	0.003*	–32.86 to –6.82
ΔBMI (kg/m2)	3.40	0.90	3.79	<0.001*	1.61 to 5.19
Time interval (months)	0.05	0.07	0.84	0.403	–0.08 to 0.18
Surgical treatment × Time	0.37	0.10	3.51	0.001*	0.16 to 0.57
Age (yr)	0.21	0.19	1.10	0.278	–0.17 to 0.58

p<0.05.
The interaction term (surgical treatment × time) represents the time-dependent effect of surgical treatment on ΔAHI compared to the untreated group. The multivariate model was adjusted for baseline AHI, age, and ΔBMI to control for potential confounding factors.
B: unstandardized regression coefficient, SE: standard error, CI: confidence interval, ΔBMI: change in body mass index.