Table 2. Mixed-effects logistic regression to identify factors associated with flatfoot adjusting for different variables.

Variables	B	E.E	P	OR	95% CI
Age (years)	0.071	0.031	0.024	1.073	(1.009; 1.141)
Gender (female)	1.267	0.529	0.017	3.549	(1.258; 10.011)
BMI (kg/m2)	0.329	0.050	<0.001	1.390	(1.261; 1.532)
Waist-to-hip ratio	0.827	2.550	0.746	2.286	(0.015; 338.883)
Charlson score	0.080	0.226	0.724	1.083	(0.696; 1.586)
Forefoot width (cm)	0.539	0.344	0.117	1.714	(0.874; 3.362)
Foot (left)	−6.13e−19	0.221	1.000	1	(0.648; 1.542)
Constant	−25.754	4.235	<0.001	—	—
Random-effects parameters	Estimate	E.E	P
Patients			<0.001
var(constant)	16.271 35	2.204 196			(12.477; 21.219)

B, regression coefficient; BMI, body mass index; CI, confidence interval; OR, odds ratio; SE, standard error.