Table 1.

Patient characteristics (frequency and percentage, unless otherwise noted)

Characteristic	Total (N=3802)		Primary participants (N=3577)		Revisional participants (n = 225)		p value*
Patient age (years), mean, median		44.22	43.98		47.95		<.001
		44.0	44.0		49.0
Patient age (years)							<.001
<30	390	10.3	380	10.6	10	4.4
30–39	990	26	952	26.6	38	16.9
40–49	1108	29.1	1043	29.2	65	28.9
50–59	991	26.1	899	25.1	92	40.9
60–64	238	6.3	225	6.3	13	5.8
65+	85	2.2	78	2.2	7	3.1
BMI (kg/m^2), mean, median		48.51	48.98		40.95		<.001
		47.0	47.3		41.2
BMI (kg/m^2)							<.001
<35	89	2.3	25	0.7	64	28.6
35–<40	391	10.3	353	9.9	38	17
40–<50	1919	50.5	1844	51.6	75	33.5
50–< 60	1019	26.8	983	27.5	36	16.1
60+	383	10.1	372	10.4	11	4.9
Male	761	20	732	20.5	29	12.9	0.01
Patient race white	3365	89.3	3159	89.1	206	92.4	0.13
missing, n	34		32		2
Hispanic	240	6.3	227	6.3	13	5.8	0.73
missing, n	1		1		0
Smoker within last							0.29
year	584	15.4	555	15.5	29	12.9
missing, n	1		1		0

^*Chi-square test for categorical variables (with continuity correction for categorical data), Kruskal-Wallis test for continuous variables