"Nightmare" on Hospital Street

Not sure how we missed last week's JAMA medical news piece featuring our very own co-blogger Dan, but I suspect we might have been distracted by something pretty terrible. The article highlights the rise of carbepenem (CRE) and 3rd-generation cephalosporin-resistant Klebsiella pneumonia strains originally described in ICHE by Braykov et al. The CDC's Arjun Srinivasan emphasized that these strains are almost exclusively hospital-associated and now is the time for hospitals to implement the latest CRE recommendations from the CDC 2012 toolkit.

Dan "emphasized the importance of infection control basics such as ensuring a high rate of hand hygiene adherence among staff and making sure that surfaces and equipment are properly disinfected."  And said "If you don't shore up those things, screening [for CRE] isn't going to help."

I'll just paste in my favorite section: "An additional problem is the piecemeal approach to tracking these infections. Only 6 states require facilities to report CRE cases. “We need a more coordinated response,” Diekema said. He explained that the CDC is doing as much as it can with the resources it has, but underfunding of public health at the national and state levels makes it difficult to mount a more coordinated national effort to contain the spread of these infections. More research is also needed on the best strategies for environmental disinfection, ensuring adherence to hand hygiene and other measures that would prevent the spread of health care–acquired infections."

CRE isn't just a nightmare, it's a recurring nightmare. And just like the nine Nightmare on Elm Street films, it'll get worse over time. Especially if we continue with the current "piecemeal approach" prevention plan.

Source: Bridget Kuehn, JAMA 4/27/2013
Image source: wikipedia

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The Environment and HAI – Where does Biological Plausibility Come In?

This May's Infection Control and Hospital Epidemiology (ICHE) contained a randomized trial of copper-coated surfaces in ICU settings which reported a 50-70% reduction in several aggregate outcomes that included hospital-acquired infections and colonization with MRSA and VRE.  In this guest blog post, physician-scientists Dr. Matthias Maiwald from the KK Women’s and Children’s Hospital in Singapore and Dr. Stephan Harbarth from University of Geneva Hospitals in Geneva, Switzerland question the plausibility of these findings and put them in the larger context of what actually causes HAIs.

In 1965, Sir Austin Bradford Hill published a landmark paper, entitled “The Environment and Disease: Association or Causation?” in which he outlined what would become known as the “Bradford Hill Criteria.” The “Hill Criteria” help distinguish association from causation in epidemiological research. One of nine criteria was biological plausibility. Quoting: “It will be helpful if the causation we suspect is biologically plausible. But this is a feature I am convinced we cannot demand. What is biologically plausible depends upon the biological knowledge of the day.” As commented elsewhere, the spirit of this criterion is to check whether the proposed causation violates any of the known laws and facts of science of biology, and as Hill outlines, this depends on currently available knowledge. It is said that Hill did not intend the criteria to be applied rigidly in the sense of a checklist approach; instead, he regarded them as “viewpoints” that would merely help in the assessment.

Fast-forward to the May 2013 Special Topic Issue of ICHE concerning the role of the environment in infection prevention. In the issue’s introduction, Weber and Rutala quote figures from a 1991 article by Weinstein concerning the biologically plausible sources of healthcare-acquired infections (HAIs): “patients’ endogenous flora, 40-60%; cross infection via the hands of personnel, 20-40%; antibiotic-driven changes in flora, 20-25%; and other (including contamination of the environment), 20%.”

In the same issue, an article by Salgado and colleagues caught our attention. This clinical trial compares 614 patients randomly placed into standard ICU rooms or into rooms where 6 frequently-touched items (e.g. bed rails, overbed tables, intravenous poles, etc.) had been replaced with copper alloy surfaces. The measured primary outcomes, according to the paper’s methods, were:
   (a) any HAIs and
   (b) colonization with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE). Besides HAI and colonization, outcomes presented in the results section included the numbers of patients who had
   (c) both HAI and colonization,
   (d) HAI and/or colonization,
   (e) HAI only but no colonization (i.e. number of patients who had HAI minus the ones who had both HAI and colonization), and
   (f) colonization only but no HAI.

Are you confused? Separate data for outcomes in each trial arm were only reported for (d-f) but not (a-c).

For HAI and/or colonization (d), the article reported what amounted to a 49% reduction in the copper rooms vs. non-copper rooms (21 vs. 41 patients; p=.02), for HAI only (e) a 62% reduction in the copper rooms (10 vs. 26; p=.013), and for colonization only (f), a 67% reduction (4 vs. 12; p=.063, NS). What was was not reported were the numbers of patients with (a) HAI and (b) colonization, listed separately for each trial arm, but the article concluded – in the discussion – that copper surfaces in rooms reduced the risk of HAIs by more than half. Conventional wisdom, however, would suggest that (a) any HAIs and (b) any colonization events, would be the most biologically relevant outcomes, and that it may not be so informative to combine these two events (under d) in the same statistical calculation, because they are biologically very different from each other. So, we extracted the missing numbers from the other numbers presented and arrived at (a) HAIs 17 vs. 29, and (b) colonization, 11 vs. 15 events. Putting these into our statistics calculator, they were – non-significant.

Now, let us revisit possible transmission routes in hospitals. We have: (i) endogenous transmission, from within the patient’s own flora, (ii) exogenous transmission via direct transfer, (e.g. as in handborne without surfaces), and (iii) exogenous transmission via surfaces and secondary transmission from surfaces onto the patients. If we look at (a) HAIs and (b) colonization with MRSA or VRE, then all three pathways can lead to HAIs, while only the two exogenous pathways can lead to colonization. If there is a >50% reduction of HAIs through copper surfaces (pathway iii), this would mean that the overall proportion of transmission from pathways (i) and (ii) plus the proportion of transmission from the remaining non-copper surfaces in the copper-treated rooms among pathway (iii) among all HAIs together would contribute less than 50% to overall HAIs.

The obvious question comes to mind: is that consistent with the known proportions of the different pathways leading to HAIs? The preliminary answer, given the Weinstein data (see above), would be, “given the biological knowledge of the day, apparently not.” It is also noted that the overall numbers of HAI and colonization events in the present article are relatively small.

Finally, anyone of us engaging in research can accidentally have outcomes that are surprising or do not quite add up with existing knowledge in the field. That is, in our opinion, where the intended purpose and scope of a discussion section of an article comes in, and where the Hill Criteria provide important food for thought. As one of us has put forward (Teleclass Feb. 7, 2013) on a different occasion and concerning a different topic, we would welcome the broad application of a check for biological plausibility when findings from clinical trials – and even systematic reviews – are reported. But we are not confident that our voices will be heard.

Image of Sir Austin Bradford Hill, source: toxipedia

Surveillance under pressure

There’s a great success story now published online in ICHE. The CDC, using National Nosocomial Infection Surveillance (NNIS) and National Healthcare Safety Network (NHSN) data, estimates that 100-200K central line associated bloodstream infections (CLABSIs) have been prevented since 1990 through implementation of evidence-based prevention practices. This accomplishment should be celebrated as a demonstration of the real progress that has been made in hospital infection prevention. As Mary Dixon-Woods and our fellow blogger Eli point out in an accompanying editorial, however, these results are also a time to reflect on how much surveillance has changed since 1990.

The CLABSI surveillance that we once performed exclusively to guide local prevention efforts is now used for much different purposes, with rates reported publicly and soon to have a real impact on each hospital’s bottom line. The pressure to bring CLABSI rates to “zero”, by any means necessary, gets passed along from hospital administrators to unit directors and infection prevention programs, turning CLABSI rates into what Mary and Eli correctly describe as a “reactive measure.” To quote their editorial,

“the more that organizations are incentivized by the prospect of shaming or financial penalties to decrease sensitivity—and thus not to find cases—the less certain it is that they are reporting a valid assessment of their infection rate”

It is instructive to examine what happens in other professions when intense pressure is brought to bear on a metric. Five minutes on The Google is enough to inform about what happens when law enforcement is under pressure to lower crime rates, or when teachers are under pressure to improve student test scores. Are police officers and teachers more inclined to “cheat” than are those tasked with counting infections in hospitals? Do officers who misclassify a burglary as a theft after receiving a call from a commander really have nothing in common with the IP program that misclassifies a primary CLABSI as secondary after a call from a unit director or hospital administrator?

This increased pressure is also felt at the CDC and NHSN, as a metric that was initially designed for one purpose is now appropriated for very different purposes. We recently performed an email survey of over 50 prominent hospital epidemiologists to gather their opinions about the direction of surveillance over the next decade. The results can be found here. Some of the highlights:

• Over 75% of those surveyed thought it likely or extremely likely that their local surveillance efforts will erode to focus only on those linked to payment policies or state/federal requirements.
• All thought that HAI surveillance metrics linked to payment policies and state/federal mandates would continue to grow to include more outcome and process measures.
• Respondents felt that pay-for-performance metrics were most likely to drive practice change (moreso than public disclosure of data, use of data by practitioners, or release of national summary statistics).
• Fewer than half thought it was likely that fully automated metrics from existing data elements would replace manual review of records for HAI determination.
• About half of respondents thought that the increased attention to HAI prevention from payment policies, mandates and public reporting has made patients safer (13% thought it hadn’t, and 40% thought the jury was still out).
• Almost 80% of respondents thought that infection prevention experts and clinical providers should have a much larger role in developing and modifying state/federal reporting requirements.

In other words, there is real concern in the HAI prevention community that the increased attention to HAIs, the drive to “zero”, the link to payment policies and public reporting requirements, is a double-edged sword. It has resulted in some tangible successes (CLABSI reductions being a prime example), but threatens to undermine our ability to respond nimbly to emerging local priorities by consuming all of our time and energy, and by producing data that no longer accurately reflect the true rate of adverse outcomes. To quote again from Mary and Eli:

"Undermining our surveillance system to serve ill-designed demands for accountability means that it may no longer be useful for monitoring and driving patient-safety improvements. That would truly be a shame."

Prevention Fund love (finally!)

At long last, someone is showing a little backbone in trying to protect the Prevention and Public Health Fund.  The fact that it's the Senator from Iowa makes it all the sweeter.  Go Tom!  The money quote from Senator Harkin:

"I am greatly disappointed that the administration chose to help pay for the Affordable Care Act in fiscal year 2013 by raiding the Public Health and Prevention Fund. The Prevention Fund works. Thanks to this funding, more children are being immunized. More people are quitting smoking. More communities are fighting chronic disease. More people are being screened for hepatitis C. Robbing prevention when we know these efforts can improve people's health and lower healthcare costs goes against the very mission of healthcare reform."

h/t to Mike for e-mailing me the link.

Give Gloves a Chance: Benefits of Mandatory Gloving Policy in Pediatrics

We spend a lot of time discussing the importance of clean hands in preventing hospital-acquired infections (HAIs). Most of the time we equate clean hands with hand-hygiene compliance and complicated and fleeting surveillance and educational programs. It would be one thing if these efforts led to compliance levels above 90%, but even the Joint Commission could barely get compliance above 80% after massive efforts.

Which leads me to one question - are we asking the wrong question?

Instead of focusing solely on driving hand hygiene compliance above 90%, perhaps we should focus on clean hands. If we ask a new question: "What do we need to do at our hospital to get healthcare worker hands to be 90% clean?", we get very different answers than if we focus solely on increasing hand rub use. For example, we could begin studying long-acting hand disinfection products that work all day or environmental cleaning products that keep hands clean in the first place. And another thing we could consider looking at is the benefits of the humble examination glove. We just published a study in Pediatrics, led by Jun Yin a PhD student in statistics, that aimed to do just that.

At the University of Iowa, we have a policy that mandates that healthcare workers wear gloves for all patient contacts during RSV season. We wanted to see if we could take advantage of this natural experiment to see what happened to HAI infection rates during the mandatory gloving periods compared to non-gloving periods.  To do that we completed a quasi-experimental study using time series analysis (Poisson regression models) on data from 2002-2010. We studied the effect in 5 units including a 20-bed PICU, a 62-bed NICU, a 5-bed Pediatric Bone Marrow Transplant Unit, a 26-bed Pediatric Hematology-Oncology Special Care Unit, and a 35-bed Pediatric Medical/Surgical Mixed Acuity Unit.

What did we find? Universal gloving periods were associated with a 25% reduction in HAI rates after adjusting for long term trends and seasonal effects. There was a 37% reduction in bloodstream infections (BSIs), a 39% reductions in central line-association BSIs and an 80% reduction in hospital-acquired pneumonias. The reductions were statistically significant in the PICU, NICU and Bone-Marrow Transplant Unit.

Yes, this unfunded study has limitations. It's a non-randomized, single center study. There could have been other factors that started just when RSV season started every year along with the gloving policy (although we couldn't think of any). Since this intervention was turned on and off every year for 9 years (with an exemption in 2009 for the novel H1N1 pandemic), it's unlikely there were other interventions that biased these results every year at the exact same time. 

Perhaps we need further study and cluster-randomized trails. We won't have to wait long. There is an important AHRQ-funded study that Anthony Harris's group is just completing at the University of Maryland that looks at the benefits of mandatory glove+gown policies in ICUs. However, this study won't tell us if it's the gowns or gloves or if they work in Pediatrics. So what do we do in the interim while waiting for future trials and magical interventions that get hand hygiene compliance above 90%?  All we are saying is "Give Gloves a Chance."

Reference: Yin J et al. Pediatrics April 22, 2013

Image: wikipedia

Media coverage: Reuters Health and Wired (Superbug)

Good riddance?

This week we suspended our tuberculin skin test program for healthcare workers due to the nationwide shortage of tuberculin. I say, Glory Hallelujah! I can't think of a more poorly performing test. Really, it's junk. And we've reached a point at our hospital that no healthcare worker will take isoniazid after a positive skin test until an interferon-gamma release assay has been done and is positive. However, there doesn't appear to be a good correlation between the skin test and the IGRA, so when the two tests are discordant, it's a coin toss as to which is the true result. To complicate matters even more, there's also a nationwide shortage of isoniazid. And don't even get me started on the use of isoniazid to treat latent TB (see here).

Photo:  Mayo Clinic

Nosocomial listeriosis

The Sydney Morning Herald is reporting that 3 patients in 2 Sydney hospitals have developed listeriosis after consuming profiteroles served to patients at the hospitals. The infecting strain in all patients was identical. One of the patients has died from an apparently unrelated cause.

Nosocomial foodborne illnesses, particularly those of bacterial origin, are seemingly uncommon. I suspect this is likely due to a lack of appetite in many hospitalized patients, and the highly processed nature of hospital foods (sometimes I'm not sure it's actually food).

A few weeks ago, while making morning rounds on the inpatient infectious diseases consult service, I went to see an immunosuppressed patient with pneumonia. As I was about to leave his room, I noted a clear plastic container of macaroni salad on his overbed table that had been served the evening before. My paranoia of foodborne infections must have been palpable. He thought it was quite funny that I alarmingly said, "Don't eat that!" While laughing at me, he said, "that's old Doc, I'm not gonna eat that." Just to be sure, I threw it in the garbage, which made him laugh all the more.

Photo: Culinary Catastrophy