SSI Prevention Bundle in Cardiac, Hip, and Knee Surgery - A Home Run

...and I'm being modest...

As I mentioned yesterday, it's really hard to write a post when you've already written the accompanying editorial. Today, I have a taller task - posting on a study led by two close colleagues (and favorite people), Marin Schweizer and Loreen Herwaldt. (COI alert) Fortunately, JAMA Associate Editor, Preeti Malani, has done the heavy lifting with her excellent editorial.

In today's JAMA, Schweizer and colleagues reported the results of an AHRQ-funded trial examining the benefits of an SSI prevention bundle in orthopedic and cardiac surgery. The bundle was outlined in a meta-analysis they published in BMJ two years ago and included preoperative nasal screening for MRSA/MSSA, mupirocin BID and daily CHG baths for 5 days if screen positive and vancomycin added to perioperative prophylaxis if MRSA positive. The quasi-experimental intervention study took place in 20 US hospitals across 9 states with 39 months of pre-intervention SSI rates and 21 months of rates collected during the intervention period.

Overall, the results are impressive (i.e. not modest). First, there was a 42% reduction in SSIs after the intervention was implemented (see Figure, below), despite modest bundle adherence (39% full adherence, 44% partial adherence).

The key finding for me relates to the number of months where there were ZERO SSIs across all 20 hospitals. Looking at the Figure above, you can see that "the number of months without any complex S aureus SSIs increased from 2 of 39 months (5.1%) to 8 of 22 months (36.4%; P = .006 by Fisher exact test)." Seven times as many zero-months in all 20 hospitals. That's not a modest finding. ;)

Key points from the editorial:

"inclusion of patients undergoing emergency or urgent operations, a population recognized as at high risk for SSI, improves the generalizability of the findings."

"the primary study outcome was limited to complex S aureus SSIs, eliminating much of the subjectivity of infection surveillance. Even though surveillance practices varied among participating hospitals, complicated S aureus SSIs are not clinically subtle and can be identified easily by any surveillance system."

and given the modest adherence to the bundle, "Moving forward, efforts to promote and maintain adherence to prevention protocols will remain important"

"The study’s setting is among its limitations. All 20 study sites were from a single health care system with a well-established quality improvement infrastructure - certain factors in this health care system may differ from other clinical settings, including a below-average baseline infection rate. It remains unclear what challenges and barriers may present as this bundle is implemented at other institutions. Further studies in different settings will offer additional guidance."

and my favorite quote:"Although getting to zero is unlikely to be achievable, efforts that move closer to this elusive goal hold tremendous value for clinicians, hospitals, payers, and, most importantly, patients."

My final thoughts:
This is a wonderful study that took many years of planning, hard work and tremendous collaborators, including HCA and Ed Septimus. Congrats to all involved. Not every study is a grand slam, but we'll take a home run for infection prevention.

Searching for an Optimal Hand Hygiene Bundle

One of the things we frequently discuss is the central role that hand hygiene compliance plays in preventing the horizontal transmission of resistant bacterial pathogens. 16 "hand hygiene" posts so far in 2013. Hand hygiene compliance is consistently lower than we wish for and it's common that healthcare workers are blamed for poor compliance. I've often mentioned the 2011 Cochrane Review of "Interventions to Improve Hand Hygiene Compliance in Patient Care" and how only 4 papers made the cut, as it struck me that the inclusion criteria were too restrictive. We then wondered if expanding the number of studies included would offer any additional guidance for developing a standardized hand hygiene improvement program.

With the support of the VA National Center for Occupational Health and Infection Control (COHIC) and VA Office of Public Health, Marin Schweizer and our group at Iowa City have completed an extensive meta-analysis of interventions (and bundles) targeting hand hygiene compliance (just published in CID). The review included all studies published from 2000-2012; The year 2000 was selected since ABHR became more widely utilized around that time. 8148 articles were identified and 46 studies were reviewed and included with 1/3 from the US and 1/3 from Europe.

There were several important findings:

1) Only 46 studies from 45 populations have been completed in over a decade. For a critical intervention, this is an unacceptably low number of studies. Funding agencies (and folks that blame HCW for poor compliance) should take note.

2) Meta-analyses of single interventions could not be performed because there were too few studies. It's surprising that we are building bundles without examining individual components first.

3) Increasing the number of interventions included in a bundle was not associated with greater improvements in compliance. For example, bundles with only 1 or 2 interventions were associated with more than a 3-fold increase in hand hygiene compliance while bundles of 3-4 or >5 interventions were associated with a smaller 2-fold improvement in compliance.

4) Several bundles were frequently studied and deemed effective. One bundle that included education, reminders, feedback, administrative support, and access to alcohol-based hand rub was associated with improved hand hygiene compliance (pooled odds ratio [OR], 1.82, Group B below) and another bundle that included education, reminders, and feedback was also associated with improved compliance (pooled OR, 1.47 - Group A below). See the figure below.

More work to do!

Reference: Schweizer ML, Reisinger HS, Ohl M, Formanek MB, Blevins A, Ward MA, Perencevich EN. Clin Infect Dis; 2013.

Save your mupirocin for SSI prevention in cardiac and orthopedic surgery

As our guest blogger, Marc-Oliver Wright, posted last week, widespread use of mupirocin was associated with 400% increase in mupirocin resistance at his hospital. Many are very concerned about widespread and non-selective use of mupirocin as a result of the REDUCE MRSA trial, particularly since the incremental benefit of mupirocin added to CHG is not known. Based on prior studies, it is possible that many of the benefits seen were due to CHG and not necessarily mupirocin.

With that in mind, why should we care about mupirocin resistance? Well, there are instances were mupirocin has more established benefits in the literature and one is in surgical site infection prevention. The issue with most infection prevention intervention studies is that most outcomes like SSIs are rare (fortunately) and research budgets are small, which leads to numerous underpowered quasi-experimental studies. The problem with this type of literature base is that it can lead to unnecessary controversy with clinicians cherry-picking study results to support their specific hypothesis.

To make use of such a literature base and scientifically determine the benefits of nasal decolonization (and other interventions), Marin Schweizer and Loreen Herwaldt at the University of Iowa completed a meta-analysis of SSI prevention intervention studies in cardiac and orthopedic surgery, which was published today in the BMJ (free open access). (COI note: I'm a co-author on the paper and was an independent reviewer/data abstracter) After screening 1423 articles published between 1995 and 2012, they identified 39 studies of moderate to high quality. 17 studies assessed the benefits of nasal decolonization (16 mupirocin and 1 nasal CHG), 15 studied glycopeptide prophylaxis and seven examined the bundle: screening+nasal decolonization+vancomycin). The pooled effects were quite impressive.

Nasal decolonization was associated with a 61% reduction in S. aureus SSIs, a 70% reduction in MRSA SSIs and a 50% reduction in MSSA SSIs. Glycopeptide prophylaxis was associated with a 60% reduction in MRSA SSIs while the full bundle was associated with a significant reduction in S. aureus, MRSA, MSSA and Gram-positive SSIs. I have pasted the table below (click to magnify), but since the full article is open access, you can also read the full article at BMJ.

This meta-analysis guided the implementation of an ongoing trial funded by AHRQ, so more data are coming soon. But what to make of this paper in the context of the recent REDUCE MRSA trial?  I myself am concerned that widespread mupirocin use in all ICU patients will select for resistant S. aureus isolates and render this highly-effective SSI bundle ineffective in short order. It will be sad to watch this example of the 'tragedy of the commons' play out in real time, as I suspect we will. And we will only have ourselves to blame. The data is right before our eyes.