Researchers find evidence of the deadly infection in care settings outside the hospital and in numbers greater than previously estimated.
Clostridium difficile infection sickened 453,000 people in the U.S. in 2011—80% more than previously reported—and was associated with 29,000 deaths that year, says a report from the Centers for Disease Control and Prevention.
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Clifford McDonald, MD |
"This is a tremendous burden of suffering and premature death, 80% of which occurs in people 65 and older who die within 30 days," says Clifford McDonald, MD, senior author of the study, which was published in the New England Journal of Medicine.
The study conducted lab-confirmed surveillance in 10 states—a population of 11.2 million people—and extrapolated the data nationally. It found a significantly larger number of cases than a 2013 CDC report which estimated 250,000 cases of C. difficile infections resulting in hospitalization which were associated with two types of care settings.
The new report looks more broadly across the healthcare continuum for infections and symptom onset and attributes acquired infections to four care settings:
- Community-associated (a positive sample is collected in an outpatient setting or within three days after hospital admission indicating infection outside the hospital)
- Community-onset associated with prior contact with a healthcare facility
- Nursing home-onset
- Hospital-onset
"This is our largest, most comprehensive snapshot, because we're looking at C. diff in the whole continuum of healthcare settings and the community," says McDonald, the CDC's senior adviser for science and integrity in the Division of Healthcare Quality Promotion. He emphasizes that the study should prompt more aggressive interventions by all healthcare facilities, especially with regard to more judicious and appropriate use of antibiotics, which predisposes patients to C. difficile illness.
Of the 453,000 cases identified, 293,000 were related to healthcare facilities. Of those infections:
- 107,600 were hospital-onset
- 104,400 were nursing home-onset
- 81,300 were community-onset associated with a healthcare facility
Additionally, although people who were treated in hospitals made up about one-third of all C. difficile infections, two-thirds of those occurred after the patients were discharged.
Also of concern is that among those infected and whose infections were resolved, often after more than a week of illness and sometimes after surgery to remove the bowel, one in five patients experienced a recurrence. Cost is another concern. It is estimated that the cost to treat C. difficile is $4.8 billion a year in added U.S. healthcare costs.
In a news conference Wednesday, CDC deputy director Michael Bell, MD, said that epidemiologists have a lot of work to do to stem the infection, especially to better understand the role of people who carry C. difficile without having symptoms, and "how much do they contribute to the transfer of infection within communities and hospitals."
Additionally, "there's a need to better understand approaches to cleaning healthcare environments," which may be one way that the infection moves through communities outside of healthcare facilities.
Antibiotics Use on the Ward
In a related study in this week's edition of JAMA Internal Medicine, researchers looked at C. difficile infection patterns in 16 wards within Toronto's Sunnybrook Health Sciences Center over four years and found that for every 10% increase in ward-level antibiotic use, there was a 34% increase in the risk of C. difficile infection.
What's more, says the study's senior author, Nick Daneman, MD, many of the patients who got sick with the infection did not themselves receive an antibiotic, but were treated in units where a lot of antibiotics were used.
"What this study shows is that it's not only your individual receipt of antibiotics that's a risk factor, but that it's the overall amount of antibiotics being used within a hospital ward, above and beyond the individual risk posed by the patient receiving an antibiotic," Daneman says.
The "hypothesis is that many of these transmissions of C. diff are from patients colonized with the bacteria but are not symptomatic," he says. "These patients can transmit the bacteria to others by contact or by contamination of the hand of healthcare workers or the environment, and result in secondary cases of the disease."
Antibiotics are a major contributor to C. difficile infections because they kill hundreds of types of bacteria that contribute to a gastrointestinal health. Prolonged antibiotic treatment, or treatment with broad spectrum antibiotics rather than medications more specifically targeted, are the culprit.
Going forward, Daneman says he is conducting a study at Sunnybrook that compares rates of C. difficile illness afterantibiotic use for seven days rather than the traditional 14 days during regimens for treating patients with bloodstream infections or sepsis.
"Amazingly, there's no data out there that says how long these people need to be treated, though we're getting more evidence emerging that shorter durations are as effective as longer-duration treatments for many other infections from pneumonia, cellulitis, and kidney infections. We already have a lot of data to think this is a safe approach. And you can imagine, if seven days is equivalent to 14, that's hundreds and hundreds of fewer days of antibiotic treatment, and far less antibiotic resistance and C. diff."
Infection Reduction Efforts
Numerous efforts are underway to reduce the burden of C. difficile, McDonald says. The Centers for Medicare & Medicaid Services now requires hospitals and long-term acute care facilities to report infections, posts hospital-specific infection rates on Hospital Compare, and has added infection rates to the value-based purchasing program algorithm for hospital payments starting Oct. 1, 2016.
The CDC is working with CMS to develop a National Quality Forum-endorsed measure that reflects healthcare facilities' use of electronic health records—perhaps as an ingredient in meaningful use requirements — to reduce antibiotic use across the facility, he adds.
Such a measure would capture practices of individual physicians, "and really bring home to hospitals and their leaders what their antibiotic prescribing by physician looks like in relation to their peers."
McDonald adds that there are numerous hurdles. EHR vendors need to incorporate that data in their products, and with the current "fragmented healthcare system, many clinicians are independent contractors and sometimes it's like herding cats. But when people can see how they are using antibiotics relative to others, I think we can get some real traction."
But some initiatives appear to be working. McDonald says that between 2011 and 2013, the CDC has tracked a 10% decrease in hospital-onset C. difficile infections.
McDonald and Bell note that U.S. healthcare settings should look to England, where through a number of strategies such as better management of how antibiotics are used, rates of C. difficile dropped by 60% over a three-year period.