New Research Uncovers Some Clues to Aid Prevention

By Brenda L. Mooney

WASHINGTON — As the VHA works to reduce the overall post-operative rate of Clostridium difficile infection (CDI), important new research has uncovered some clues to the circumstances that increase risk for the infection.

The rate of CDI, which can cause severe diarrhea and life-threatening intestinal conditions, was 0.4% per year among more than 468,386 surgical procedures at the VHA, according to a study recently published in JAMA Surgery.1

Study authors note that the VHA rate is on the low end. A 2010 study published in the journal Surgery reported that CDI rates among patients who underwent abdominal surgery at a teaching hospital in New York were as much as 1.2%.2

Perhaps more significantly, the research team from the VHA’s National Surgery Office and colleagues identified indicators associated with more cases of the post-operative infection.

“To our knowledge, this is the first study to report that the rate of postoperative CDI is significantly associated with the number of antibiotic classes administrated within 60 days before surgery,” wrote the authors led by Xinli Li, PhD. “To our knowledge, this is also the first study to report that the rate of postoperative CDI is significantly associated with the complexity of the surgical procedure and the complexity of the surgical program in which the procedure is performed.”

Already known risk factors for CDI include older age, severe coexisting illnesses, hospitalization and antibiotic use.

With more than 400,000 surgical procedures annually, the Veterans Affairs Surgical Quality Improvement Program (VASQIP) started collecting 30-day post-operative CDI data in eligible non-cardiac surgical procedures in 2007.

For this study, researchers documented CDI incidence in the VHA over a four-year period from October 2009 through September 2013 across different surgical procedures. They sought to identify risk factors associated with CDI while determining how the infection affects post-operative death rates, illness and hospital length of stay (LOS).

Results indicated that, among 468,386 surgical procedures, 1,833 cases of 30-day post-operative CDI were diagnosed. Most, 1,239 patients or 67.6%, were diagnosed as having CDI during the initial hospitalization, while others were diagnosed as having a CDI on readmission or as outpatients.

Overall, 30-day CDI rates were higher in emergency procedures and procedures including those with greater complexity and those with a contaminated/infected wound classification, according to the results.

In addition, patients with post-operative CDI tended to be older, were more frequently hospitalized after surgery, had longer pre-operative hospital stays and had received three or more classes of antibiotics. CDI patients, compared to those without the infection, had higher rates of post-operative illness (86% vs. 7.1%), dying within 30 days (5.3% vs. 1%) and longer post-operative LOS (17.9 days vs. 3.6 days).

“The CDI rate of cases with three more different antibiotic classes prescribed was almost six times higher than that for cases with no or only one antibiotic class prescribed within 60 days before surgery,” the researchers wrote.

Specifically, independent risk factors for CDI were found to be:

  • advanced age,
  • albumin less than 3.5 g/dL,
  • higher ASA classification,
  • bleeding disorder,
  • dialysis,
  • impaired functional status,
  • hematocrit less than 38%,
  • hemiplegia,
  • history of chronic obstructive pulmonary disease,
  • pain/gangrene,
  • open-wound infection,
  • weight loss greater than 10% within six months before surgery,
  • duration of hospitalization before surgery, and
  • pre-operative cumulative antibiotic use.

At the same time, C. Diff infection rates differed among surgery specialties, with transplant surgery having the highest CDI rate at 2.37%, according to the study, which points out that there were no CDI cases among oral surgery procedures during the four-year period. Gynecological surgery also had a low rate of 0.06%.

That contrasts with a CDI rate of 2.6% and 3.1% for kidney and lung transplant cases, respectively, according to study authors, who noted that is still relatively low, considering some study found CDI rates after solid organ transplant to be as high as 12.4%.

“Surgical administrators and clinical teams may consider the results of this study to target interventions for specific patients undergoing high-risk procedures,” the authors concluded. “Such interventions include selective antibiotic administration, early testing of at-risk patients, hand hygiene with non-alcohol agents, early contact precautions and specific environmental cleaning protocols. The results of this study can help inform best practice and provide actionable data to VHA leadership for the prevention of future increases in CDI rates.”

In a related commentary, Paul K. Waltz, MD, and Brian S. Zuckerbraun, MD, of the VA Pittsburgh Healthcare System, noted, “What is to be highlighted is the twelvefold increase in morbidity and fivefold increase in mortality associated with CDI [Clostridium difficile infection] compared with postoperative patients without CDI.”3

“While CDI can directly lead to clinical deterioration resulting in increased morbidity and mortality, this may also suggest that patients who develop CDI have an impaired immune response and are a vulnerable population for other hospital-acquired infections and poor outcomes,” Waltz and Zuckerbraun wrote. “Taken together, this article adds to our understanding of CDI and underscores the importance of infection control and prevention strategies, including antibiotic stewardship. These findings also support the importance of the development of prophylactic strategies, expeditious recognition of CDI, adequate supportive care and improved therapies.”

1 Li X, Wilson M, Nylander W, Smith T, Lynn M, Gunnar W. Analysis of Morbidity and Mortality Outcomes in Postoperative Clostridium difficile Infection in the Veterans Health Administration. JAMA Surg. 2015 Nov 25:1-9. doi: 10.1001/jamasurg.2015.4263. [Epub ahead of print] PubMed PMID: 26606675. 

2 Southern WN, Rahmani R, Aroniadis O, Khorshidi I, Thanjan A, Ibrahim C, Brandt LJ. Postoperative Clostridium difficile-associated diarrhea. Surgery. 2010 Jul;148(1):24-30. doi: 10.1016/j.surg.2009.11.021. Epub 2010 Feb 8. PubMed PMID: 20116817; PubMed Central PMCID: PMC2886164.

3 Waltz PK, Zuckerbraun BS. The High Stakes of Postoperative Clostridium difficile Infection. JAMA Surg. 2015 Nov 25:1. doi: 10.1001/jamasurg.2015.4254. [Epub ahead of print] PubMed PMID: 26606279.