Table 3.
Univariate Comparisons of Risk Factors in Patients With and Without Breast Incisional SSI
| Characteristic | No. (%) patients with breast SSI (n = 57) | No. (%) uninfected patients (n = 268) | Odds ratio (95% CI) | p |
|---|---|---|---|---|
|
| ||||
| Body mass index | ||||
| 25 or less | 15 (26) | 89 (33) | ||
| 25–30 | 10 (18) | 88 (33) | 0.7 (0.3,1.6) | .365 |
| 30–35 | 15 (26) | 45 (17) | 2.0 (0.9,4.4) | .095 |
| > 35 | 17 (30) | 46 (17) | 2.2 (1.0,4.8) | .049 |
|
| ||||
| Obesity (BMI > 30) | 32 (56) | 91 (34) | 2.5 (1.4,4.5) | .002 |
|
| ||||
| Diabetes | 12 (21) | 37 (14) | 1.7 (0.8,3.4) | .165 |
|
| ||||
| Any glucose > 200 mg/dLa | 10 (20) | 22 (12) | 1.9 (0.8,4.4) | .116 |
|
| ||||
| Diabetes or any glucose > 200 mg/dLa | 14 (25) | 40 (15) | 1.9 (0.9,3.7) | .076 |
|
| ||||
| Current smoking or quit within past 6 months | 12 (21) | 38 (14) | 1.6 (0.8,3.3) | .192 |
|
| ||||
| ASA class 3 or 4 | 21 (37) | 54 (20) | 2.3 (1.2,4.2) | .007 |
|
| ||||
| Skin disorders at time of surgery | 10 (18) | 29 (11) | 1.8 (0.8,3.8) | .156 |
|
| ||||
| Prior chest irradiation | 12 (21) | 39 (15) | 1.6 (0.8,3.2) | .220 |
|
| ||||
| Previous chemotherapy (any) | 16 (28) | 47 (18) | 1.8 (1.0,3.5) | .068 |
|
| ||||
| Recent chemotherapy (within 6 months before surgery) | 9 (16) | 29 (11) | 1.5 (0.7,3.5) | .289 |
|
| ||||
| Tamoxifen therapy at time of surgery | 9 (16) | 25 (9) | 1.8 (0.8,4.1) | .148 |
|
| ||||
| Breast biopsy within 1 year | ||||
| None | 13 (23) | 91 (34) | ||
| Needle only | 23 (40) | 93 (35) | 1.7 (0.8,3.6) | .145 |
| Any open biopsy or surgery | 21 (37) | 84 (31) | 1.8 (0.8,3.7) | .145 |
|
| ||||
| Mastectomy | ||||
| No mastectomy | 8 (14) | 90 (34) | ||
| 0–2 lymph nodes removed | 13 (23) | 45 (17) | 3.3 (1.3,8.4) | .015 |
| ≥3 lymph nodes removed | 36 (63) | 133 (50) | 3.0 (1.4,6.9) | .007 |
|
| ||||
| Axillary dissectionb | 34 (60) | 134 (50) | 1.5 (0.8,2.6) | .186 |
|
| ||||
| Current breast cancer | 45 (79) | 174 (65) | 2.0 (1.0,4.0) | .040 |
|
| ||||
| Current or past breast cancer | 54 (95) | 204 (76) | 5.6 (1.7,18.7) | .002 |
|
| ||||
| Current diagnosis | ||||
| None/history of malignancy | 12 (21) | 94 (35) | ||
| Carcinoma in situ only | 9 (16) | 21 (8) | 3.4 (1.3,9.0) | .016 |
| Invasive carcinoma | 36 (63) | 153 (57) | 1.8 (0.9,3.7) | .088 |
|
| ||||
| Breast implant | ||||
| No implant | 36 (63) | 225 (84) | ||
| Permanent implant | 6 (11) | 13 (5) | 2.9 (1.0,8.1) | .044 |
| Tissue expander | 15 (26) | 30 (11) | 3.1 (1.5,6.4) | .002 |
|
| ||||
| Local infiltration of anesthetic agent | 7 (12) | 65 (24) | 0.4 (0.2,1.0) | .048 |
|
| ||||
| Reduction surgery only | 3 (5) | 68 (25) | 0.2 (0.0,0.5) | .001 |
|
| ||||
| Sub-optimal prophylactic antibiotic dose | 29 (51) | 78 (29) | 2.5 (1.4,4.5) | .001 |
|
| ||||
| Sub-optimal timing of prophylactic antibiotic (none, or > 60 minutes before or after incision) | 10 (18) | 50 (19) | 0.9 (0.4, 2.0) | .844 |
|
| ||||
| Any sub-optimal timing of prophylactic antibiotic administration (sub-optimal timing of 1st dose as above, or for surgeries with duration > 6 hrs, no 2nd dose or 2nd dose > 6 hrs after incision) | 15 (26) | 65 (24) | 1.1 (0.6, 2.1) | .743 |
|
| ||||
| Estimated blood loss during operation (mL)c | ||||
| ≤50 | 17 (29.8) | 77 (28.7) | ||
| 51 – 200 | 19 (33.3) | 104 (38.8) | 0.8 (0.4, 1.7) | .605 |
| 201 – 499 | 17 (29.8) | 66 (24.6) | 1.2 (0.6, 2.5) | .686 |
| ≥500 | 4 (7.0) | 21 (7.8) | 0.9 (0.3, 2.8) | .808 |
|
| ||||
| Transfusion | 9 (16) | 21 (8) | 2.2 (1.0,5.1) | .060 |
a
Serum glucose from blood collected during preoperative clinic visit or in the hospital before surgery, or within 5 days after surgery.
b
Axillary dissection as described in operative note
c
Estimated blood loss was missing for 46 patients (17.2%), and was assumed to be ≤ 50 mL for analysis. The results did not change when these patients were excluded from analysis.