Figure. Criteria for a diagnosis of infection and initiation of antibiotic therapy. The same criteria were used for both sutured wounds and those healing by second intention.
Lilly E, Schmults CD. A Comparison of High- and Low-Cost Infection-Control Practices in Dermatologic Surgery. Arch Dermatol. 2012;148(7):859-861. doi:10.1001/archdermatol.2012.602
Author Affiliations: Mohs and Dermatologic Surgery Center, Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
Though several studies have examined infection risk in dermatologic surgery, studies comparing costs of different infection control protocols are lacking. This study was undertaken to determine whether a low risk of infection could be maintained with a low-cost infection-control protocol.
A prospective study of 573 consecutive patients with 670 tumors undergoing Mohs surgery with same-day reconstruction or second-intention healing evaluated whether a low rate of surgical site infection (SSI) could be maintained with a low-cost infection-control protocol. Surgical site infections were tracked from January through September 2010 in a single-surgeon academic Mohs practice (termed low-cost group), and these were compared with those from a previously published group of 585 cases in which the infection rate had dropped from 2.5% (the practice's initial infection rate) to 0.9% with initiation of a more stringent but expensive infection-control protocol (high-cost group).1 The infection-control protocols investigated are summarized in Table 1. The study was approved by the Partners Human Research Office.
Infection was defined as any case in which antibiotic therapy was used for suspected wound infection. Criteria for determining the presence of infection and initiating antibiotic therapy are summarized in the Figure. Patients were seen for suture removal or for wound check (in cases of second-intention healing) at postoperative day 7 to 10. The presence or absence of infection was assessed at this visit. In addition, all patients were given an instruction sheet on the day of surgery describing symptoms of infection (redness, pain, swelling, fever, or pus) with instructions to come to the office for evaluation if these symptoms occurred. Wounds were cultured before antibiotic therapy was begun in all cases.
Surgical skin preparation differed between groups because chloroxylenol, 3%, became commercially unavailable during the study period. This likely had little impact on results because the efficacy of chloroxylenol and iodine skin preparations are reportedly equivalent.2 There were no personnel changes, and resident participation was consistent (approximately 20% of cases) between the groups.
Potential confounders that differed significantly on χ2 test results between infection control protocol groups were tested for association with the primary study outcome (presence or absence of infection) via the Fisher exact test. Statistical significance was set at P < .05 (STATA 9; StataCorp LP).
The cost of infection control per case was calculated by tabulating the costs of infection-control protocols for a 1-stage Mohs procedure and reconstruction performed by 1 surgeon and 1 assistant (Table 1). The cost per infection prevented was calculated by dividing the cost of infection control per case by the reduction in infection risk from the baseline risk of 2.5%.
Patients in the low-cost group were statistically different from those in the high-cost group with regard to several variables (Table 2). However, none of these variables was significantly associated with infection on Fisher exact testing (data not shown), indicating that there was no confounding of infection risk due to these between-group differences.
Infection risk was the same between high-cost (n = 5, 0.9%) and low-cost groups (n = 5, 0.7%). The cost of infection control per case was lowered from $14.62 in the high-cost group to $6.22 in the low-cost group. Compared with the baseline cost of $3.76 and infection risk of 2.5% previously published,1 the high-cost group had a $10.86 cost increase per case and a 1.6% drop in infection risk, whereas the low-cost group had a $2.46 increase in cost and a 1.8% drop in infection risk. This corresponds to a cost per infection prevented of $678.75 for the high-cost group and $136.67 for the low-cost group ($10.86/0.016 and $2.46/0.018, respectively).
This study indicates that low-cost infection-control protocols can be implemented without impacting infection risk in office-based Mohs surgery. The cost per infection prevented was reduced to $136.67, which is likely cost-effective, since the costs associated with diagnosing and treating surgical site infections (including physician time, patient time and discomfort, and costs of wound cultures and antibiotic therapy) exceed this amount.
Infection-control costs were reduced by eliminating sterile gloves during Mohs stages, and sterile gowns and half-sheet drapes during reconstruction. It may be possible to further reduce costs without altering infection rate by using clean, nonsterile gloves during reconstruction as well.3,4 Since infection risks for Mohs and general dermatologic surgery are similarly low,5 the low-cost infection-control protocol described herein may be applicable to all office-based dermatologic surgery.
The major limitation of this study is its single-surgeon practice setting. There may be factors unique to this study site or staff that are not generalizable to others. In addition, since the 3 changes in the low-cost protocol were made simultaneously, the impact of each individual change cannot be evaluated. However, infection-control measures are frequently implemented and studied as regimens involving several elements. A randomized, multicenter trial comparing infection regimens would eliminate the possibility of bias from use of historical controls and enhance generalizability of results. Such studies are needed to define optimally cost-effective infection-control protocols in the dermatologic surgery patient population.
Correspondence: Dr Schmults, Mohs and Dermatologic Surgery Center, Department of Dermatology, Brigham and Women's Hospital, 1153 Centre St, Ste 4349, Jamaica Plain, MA 02130 (firstname.lastname@example.org).
Accepted for Publication: February 3, 2012.
Author Contributions: Both authors had full access to all of the data in the study and take responsibility for the integrity and the accuracy of the data analysis. Study concept and design: Schmults. Acquisition of data: Lilly. Analysis and interpretation of data: Lilly and Schmults. Drafting of the manuscript: Lilly. Critical revision of the manuscript for important intellectual content: Lilly and Schmults. Statistical analysis: Schmults. Administrative, technical, and material support: Lilly. Study supervision: Schmults.
Financial Disclosure: None reported.