Table 2

Adjusted HRs for secondary palate surgery

Risk factor	Secondary palate surgery*
Risk factor	HR (95% CI)	p Value
Sex		0.70
Male	0.98 (0.87 to 1.10)
Female	Reference
Race		0.10
White	Reference
Black	0.75 (0.58 to 0.97)
Asian or Pacific Islander	1.01 (0.77 to 1.32)
American Indian	1.09 (0.59 to 2.02)
Other	0.97 (0.81 to 1.18)
Not specified	1.28 (0.99 to 1.65)
Median annual household income of ZIP code		0.16
$33 525 or less (<1.5 FPL†)	Reference
$33 526–$44 700 (1.5–2 FPL)	0.95 (0.82 to 1.10)
$44 701–$67 050 (2–3 FPL)	0.84 (0.72 to 0.98)
$67 051 or more (>3 FPL)	0.91 (0.74 to 1.14)
Age at primary palate repair		<0.001
<9 months‡
At baseline	6.74 (5.20 to 8.73)
At 1 year after repair	4.70 (3.44 to 6.43)
At 5 years after repair	1.11 (0.66 to 1.89)
9–15 months	1.15 (0.94 to 1.42)
16–24 months	Reference
Postoperative antibiotic use		0.06
None	Reference
Yes	0.86 (0.74 to 1.01)
Surgeon procedure volume (on day of repair)		0.17
Low (<10 repairs in prior year)	Reference
Medium (10–25)	1.11 (0.94 to 1.31)
High (>25)	1.25 (0.99 to 1.58)
Hospital procedure volume (on day of repair)		0.14
Low (<25 repairs in prior year)	Reference
Medium (25–50)	0.94 (0.77 to 1.14)
High (>50)	0.78 (0.60 to 1.02)
Length of stay after surgery		0.33
≤1 night	1.07 (0.94 to 1.22)
≥2 nights	Reference

Model assumes clustering of patients within surgeons and clustering of surgeons within hospitals; p<0.001 for likelihood-ratio tests of theta=0 for both surgeon and hospital.
†FPL, US Federal Poverty Level for a family of four.
‡Age less than 9 months at primary repair is a time varying covariate, with baseline HR 6.74 (5.20−8.73) that decreases by 30% (26–34%) each subsequent year.