499. Incidence of Surgical Site Infection Following Mastectomy With and Without Immediate Reconstruction Using Private Insurer Claims Data
Session: Poster Abstract Session: Surgical Site Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: The National Healthcare Safety Network (NHSN) classifies both mastectomy and breast reconstruction as "clean procedures" with expected 1-2% incidence of surgical site infection (SSI). However, reported mastectomy SSI rates vary widely by procedure type, length of follow-up, and surveillance method.

Methods: We used commercial claims data to establish a retrospective cohort of women aged 18 – 64 years with ICD-9-CM procedure or CPT-4® codes from facility or provider claims for a mastectomy from 1/1/04 – 12/31/08. SSIs ≤ 180 days after mastectomy were identified by ICD-9-CM diagnosis codes. Preexisting infections were accounted for in order to identify incident SSIs. We censored SSIs that occurred ≤ 180 days after mastectomy but followed a different NHSN operation. The incidence of SSI after mastectomy +/- immediate reconstruction (IR) was compared by the chi-square test.

Results: 12,209 mastectomy procedures among 11,770 women were performed during the study period; the mean age was 50.4 (standard deviation=8.5). The overall SSI rate following mastectomy with or without IR was 7.7% (935/12,209). IR was performed in 6,556 (54%) procedures. The SSI was first coded within 2-30 days post mastectomy in 50.3%, 23.0% within 31-60 days, 9.8% within 61-90 days, and 16.9% within 91-180 days. The incidence of SSI was 5.2% (294/5,653) after mastectomy only, 9.7% (458/4,721) after mastectomy plus immediate implant, 10.3% (147/1,426) after mastectomy plus flap, and 8.8% (36/409) after mastectomy plus flap and implant (p<0.001). In mastectomies with IR, the SSI rate was higher after bilateral compared with unilateral procedures (10.9% vs. 8.9%, p=0.006).

Conclusion: The incidence of SSI was higher after mastectomy with IR compared with mastectomy only and higher after bilateral compared with unilateral IR procedures. Although these procedures are all classified as “breast surgeries” by NHSN, there is significant variation in SSI incidence depending on the specific procedure type. The SSI incidence in our large, geographically diverse cohort of younger women was higher than expected for clean procedures. Only half of all SSIs were coded on medical claims ≤ 30 days of surgery, suggesting that longer term post mastectomy SSI surveillance is warranted.

Margaret A. Olsen, PhD, MPH1,2, Katelin B. Nickel, MPH1, Ida K. Fox, MD3, Julie A. Margenthaler, MD, FACS4, Kelly E. Ball, BSN, MPH1, Daniel Mines, MD, MSCE5, Anna E. Wallace, MPH5 and Victoria J. Fraser, MD1, (1)Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, (2)Division of Public Health Sciences, Washington University School of Medicine, St. Louis, MO, (3)Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO, (4)Division of General Surgery, Washington University School of Medicine, St. Louis, MO, (5)HealthCore, Inc., Wilmington, DE

Disclosures:

M. A. Olsen, None

K. B. Nickel, None

I. K. Fox, None

J. A. Margenthaler, None

K. E. Ball, None

D. Mines, None

A. E. Wallace, None

V. J. Fraser, None

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