Table 7. Association between Patient or Surgeon Characteristics and Second Surgery within 14 days of First Surgery (N=1,031,961patients^a).

	Relative Risk (95% CIb) of 2nd surgery <= 14 days after 1st surgery
	Unadjusted	Adjusted
Patient Characteristics
Female	Reference	Reference
Male	1.13 (1.12, 1.14)	1.11 (1.10, 1.12)
Age (years)
65-74	Reference	Reference
75-84	0.80 (0.80, 0.81)	0.82 (0.81, 0.83)
85+	0.70 (0.69, 0.71)	0.72 (0.71, 0.74)
Race
White	Reference	Reference
Black	0.72 (0.70, 0.73)	0.73 (0.71, 0.75)
Hispanic	0.76 (0.73, 0.79)	0.87 (0.83, 0.90)
Asian	0.56 (0.53, 0.59)	0.69 (0.65, 0.72)
Other Racec	0.76 (0.73, 0.80)	0.78 (0.74, 0.82)
Surgeon Characteristics
Annual Surgical Volume
1-50	Reference	Reference
51-200	1.61 (1.55, 1.68)	1.56 (1.50, 1.63)
201-500	2.77 (2.66, 2.88)	2.57 (2.47, 2.67)
501-1000	4.04 (3.88, 4.20)	3.63 (3.48, 3.78)
1001+	6.82 (6.55, 7.10)	6.04 (5.81, 6.30)
Years of Experience (since med school graduation through 2004)
1-10 yrs	Reference	Reference
11-20 yrs	1.13 (1.11, 1.15)	0.95 (0.93, 0.96)
21-30 yrs	1.08 (1.06, 1.10)	0.84 (0.83, 0.86)
31+ yrs	1.08 (1.06, 1.10)	0.83 (0.81, 0.84)
Place of Service
Hospital	Reference	Reference
ASCd	1.66 (1.64, 1.67)	1.35 (1.33, 1.36)

^aMissing data: n=975 with unknown race; n=1086 with unknown surgeon years of experience; n=22548 with inaccurate service location

^bCI=Confidence Interval

^cOther Race includes North American Natives and “other” from the Medicare classification.

^dASC=Ambulatory Surgery Center