sinaiem.org

That is the question…

And a group of researchers at the Integrated Soft Tissue Infection Services (ISIS) Clinic at San Francisco General Hospital attempted to answer it with a randomized, double-blind, placebo-controlled trial (Editor’s note: This Journal Club recap, written by guest-blogger Jennifer, covers a paper by Rajendran et al. in Antimicrobial Agents and Chemotherapy, Nov. 2007; pdf and background articles here). Patients who met rather broad inclusion criteria (including febrile and immune deficient patients) were treated with incision and drainage, and then randomized to receive either cephalexin or placebo.

The results? There was no significant difference between the “treatment” arm of the study and the “placebo” arm of the study.

Although the study design seems reasonable, several holes in the investigators’ plan were brought up at this month’s Journal Club.

A survey at the ISIS Clinic found that 87% of physicians discharged patients with antibiotics, and 80% of those were prescribing antibiotics that are ineffective against CA-MRSA in clinical trials. Of ineffective antibiotics being prescribed, cephalexin was by far the most commonly used drug.

What does this mean for the “placebo-controlled” trial? With an ineffective drug being tested against a placebo, is there really any comparison being made? Was this study nothing more than a single-armed study evaluating the effectiveness of incision and drainage of abscesses, with no virtually no antibiotic contribution to cure rates? For all intents and purposes, the study only validates incision and drainage without addressing antibiotic treatment at all.

Furthermore, with self-reported treatment adherence rates of 72.2% for cephalexin and 78.0% for placebo, it’s hard to say that cephalexin was really tested at all. The only “standardized” treatment in the study was incision and drainage of abscesses. But how do emergency physicians and surgeons compare when it comes to I&D? Do we all cut the same? How deep do we cut? How long is our incision? Is it possible to standardize a procedure performed by more than one surgeon?

Although efforts were taken to standardize treatment, the study did fail to explore one other very important aspect of treatment – long-term outcomes. As patients were only followed for 7 days, it’s impossible to draw any conclusions regarding long-term outcomes. Did patients who received antibiotics have fewer recurrences? Did patients who received antibiotics contribute to future drug resistance? Though cephalexin has relatively few side effects, several drugs that are effective against MRSA have side effects that could limit adherence to treatment. Allergies, sensitivity to sunlight, and other untoward effects of antibiotics may make a study with a true treatment arm difficult to perform.

ACEP upholds the following when it comes to antibiotics for abscess treatment:

  -No antibiotics are recommended for an otherwise healthy patient with no risk factors, who has no signs of systemic illness and an isolated cutaneous abscess. Primary treatment is appropriate I&D, packing, and culture. If there is concern for surrounding cellulitis, consider using a beta-lactam antibiotic in those patients without risk factors for CA-MRSA if the local prevalence is less than 15%-20%.

- In patients with mild immune suppressive diseases, such as diabetes, or those who have early systemic illness, follow the same guidelines as above, except consider initiating CA-MRSA antimicrobial coverage with TMP-SMX, a tetracycline, or clindamycin as guided by your local susceptibilities

- For those patients with severe disease, immediate recognition of potential CA-MRSA involvement is essential. Consider empiric linezolid or vancomycin therapy while initiating any appropriate resuscitation efforts.

Most of the time, a good I&D with packing should be sufficient. Keep in mind that a good history will identify those who may require antibiotics, and when choosing an antibiotic, go with something that will have more than a placebo effect.

Thank you, Jennifer! I would only add something that came out of our small-group discussion, namely, that any clinic that somehow inspired these high-risk, low socieconomic-status, chronically-ill patients to come in daily for wound checks was probably going that have pretty good outcomes regardless of medication (I’d like to see a trial quantifying the effect of this amazing clinic). Applicability to some of our ED patients, with likely poorer followup, is somewhat tenuous.

Posted on Monday, September 22nd, 2008 at 2:44 am by Nick. Filed under Wound Care, Infectious Disease, Journal Club, Blog.
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