Patients who are immunocompromised showed no increased risk of surgical site infection when undergoing Mohs micrographic surgery, regardless of whether or not they received antibiotics, suggesting that antibiotic prophylaxis, which is often used for these patients, may not be necessary, according to new research.
Dr Tuyet Nguyen
The retrospective cohort study found that “immunosuppressed patients had similar infection rates as immunocompetent patients following Mohs micrographic surgery,” first author Tuyet A. Nguyen, MD, of the Department of Dermatology, Cedars-Sinai Medical Center, Los Angeles, told Medscape Medical News.
“Therefore, antibiotic prescribing patterns should not change simply due to immunosuppression. Furthermore, immunosuppressed patients appear to respond well to antibiotics and recover similarly to immunocompetent patients,” she said.
The study was presented at the American College of Mohs Surgery (ACMS) 2022 Annual Meeting.
Mohs surgery is increasingly being performed for patients who are immunosuppressed because of the higher incidence of skin cancer in this group of patients and their higher risk of more aggressive skin cancers.
Overall, the rate of surgical site infections following Mohs surgery generally ranges from 0.5% to 2.4%. However, research is lacking on the risk among patients who are immunosuppressed and on how effective the use of prophylactic antibiotics is for these patients.
For the retrospective study, Nguyen and her colleagues evaluated data on 5886 patients who underwent Mohs surgery at Cedars-Sinai between October 2014 and August 2021. Among these patients, 741 (12.6%) were immunocompromised.
Causes of immunosuppression in the cohort included the following: immunosuppression after transplant surgery; having HIV, chronic myeloid leukemia, multiple myeloma, or other hematogenous forms of immunosuppression; or immunosuppression related to other conditions, such as chronic inflammatory diseases.
Overall, postprocedural infections occurred in 1.6% (95) of patients, a rate that mirrors that of the general population, Nguyen noted. No significant differences in surgical site infection rates were observed between immunocompromised patients (2.1%, n=15) and those who were immunocompetent (1.6%, n = 80; P = .30).
Importantly, among those who were immunocompromised, the rates of infection were not significantly different between those who did receive antibiotics (3.0%, n = 8) and those who did not receive antibiotics (1.5%, n = 7; P = .19).
The lack of a difference in surgical site infection rates among those who did and those who did not receive antibiotics extended to the entire study population (2.0% vs 1.4%; P = .12).
Dr Nima Gharavi
The study cohort mainly comprised immunosuppressed transplant patients, notably, heart, lung, and kidney transplant patients. However, “even in this population, we did not see a higher rate of infection,” senior author Nima M. Gharavi, MD, PhD, director of dermatologic surgery and Mohs micrographic surgery and associate professor of medicine and pathology and laboratory medicine at Cedars-Sinai Medical Center, told Medscape Medical News.
Yet the risk of infection among those patients has been shown to be high and of consequence. Data indicate that infections account for 13% to 16% of deaths among kidney and heart transplant patients and up to 21% of deaths among lung transplant patients. The rate of mortality appears to parallel the level of immunosuppression, Nguyen explained.
Furthermore, up to 25% of patients who undergo heart and lung transplantation develop bacteremia.
In terms of why worse infections or bacteremia surgeries may not occur in association with Mohs, Nguyen speculated that, as opposed to other surgeries, those involving the skin may benefit from unique defense mechanisms.
“The skin is a complex system in its defense against foreign pathogens and infectious agents,” she explained during her presentation. “There is the physical barrier, the antimicrobial peptides, and an adaptive as well as innate immune response.
“In immunosuppressed patients, with the decrease in adaptive immunity, it’s possible this loss is less important because the skin has such a robust immune system in general.”
In her presentation, Nguyen noted that “further studies are necessary to investigate why patients aren’t presenting with greater severity, and we plan to try to investigate whether the unique nature of skin-mediated immunity makes this organ less susceptible to severe or life-threatening infections in patients on immunosuppression.”
Of note, the rate of prophylactic antibiotic prescriptions was no higher for those who were and those who were not immunosuppressed (37.9% vs 34.1%; P = .14), which Nguyen said is consistent with recommendations.
“Immunosuppression is not an indication for antibiotic use, and hence, we did not have a higher rate of antibiotics use in this population,” she told Medscape. However, a 2021 ACMS survey found that a high percentage of Mohs surgeons prescribe antibiotics for procedures in whch antibiotics are not indicated so as to reduce the risk of infections and that immunosuppression is a common reason for doing so.
The authors have disclosed no relevant financial relationships.
American College of Mohs Surgery (ACMS) 2022 Annual Meeting: Presented May 12, 2022.
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