Journal watch: recent studies of note

Recent studies about C. diff. infections, antibiotic use at teaching hospitals, and other topics.

C. diff. infections at hospitals higher than thought, study reports

A new study estimates that 13 out of every 1,000 inpatients are either infected or colonized with Clostridium difficile (C. diff), significantly higher than previous estimates.

The study by the Association for Professionals in Infection Control and Epidemiology (APIC) reported that there are at least 7,178 infected inpatients on any given day in American hospitals, with an associated cost of $17.6 million to $51.5 million. The study is based on data collected by APIC's 12,000 members on one day between May and August 2008, and represent 12.5% of all U.S. medical facilities.

According to the survey, 54.4% of patients with C. diff. infection were identified within 48 hours of admission and 84.7% were on the medical services, suggesting that the majority of patients were already infected upon admission. A study author urged hospitals to look for patients with severe diarrhea and promptly institute precautions to prevent spreading the infection if C. diff. is suspected.

APIC's “Guide to the Elimination of Clostridium difficile in Healthcare Settings” makes the following recommendations:

  • risk assessment to identify high-risk areas for CDI;
  • a surveillance program to provide early identification of CDI cases;
  • adherence to CDC hand hygiene guidelines;
  • use of contact precautions (e.g., gloves, gowns and separating CDI patients from other patients);
  • environmental and equipment cleaning and decontamination, especially items that are close to patients such as bedrails and bedside equipment; and
  • antimicrobial stewardship programs with focus on restriction of antibiotics associated with CDI and unnecessary antimicrobial use.

Antibiotic use on the rise at teaching hospitals

Use of antibiotics increased at academic medical centers between 2002-06, driven by a surge in prescriptions for vancomycin, a recent study reported.

In the study, the average total antibacterial use at 22 hospitals that reported five-year data increased from 798 days of therapy for every 1,000 patient days in 2002 to 855 per 1,000 patient days in 2006. In 2006, 63.5% of the patients discharged from 35 reporting hospitals received an antibiotic. The study appears in the Nov. 10 Archives of Internal Medicine.

Fluoroquinolones were the most commonly prescribed class of antibiotics, the study found, while the mean use of vancomycin alone increased by 43% over the five-year period, making it the single most commonly used antibiotic at the participating hospitals between 2004-06.

The authors said the findings underscore the importance of antimicrobial stewardship programs and aggressive infection control efforts, including stopping antibiotics when appropriate, switching to more narrow-spectrum drug regimens and optimal dosing using pharmacokinetic and pharmacodynamic principles. The study was funded in part by an investigator-initiated grant from Bayer.

Study connects predicted probability of thrombolysis to PE mortality

Thrombolysis was associated with a significantly higher risk of death among hospitalized pulmonary embolism (PE) patients who are hemodynamically uncomplicated, according to a recent study.

Research published in the Archives of Internal Medicine evaluated data from a statewide Pennsylvania sample. It found that both during the hospitalization and in the 30 days following admission, almost one-third of the deaths among patients who received thrombolysis and about 15% of deaths among patients who did not receive thrombolysis occurred in a small subgroup of hemodynamically unstable patients.

The unadjusted overall 30-day mortality rate for patients who received thrombolytic therapy was 17.4% compared with 8.6% for those who did not. Risk of in-hospital and 30-day mortality appears to be elevated for patients who were unlikely candidates for this therapy, but not for patients with a relatively high predicted probability of receiving thrombolysis. Furthermore, patients who received thrombolytic therapy were less likely to have diagnoses of lung disease, heart failure, and/or cerebrovascular disease and more likely to have diagnoses of ischemic heart disease, pulmonary vascular disease, and/or syncope.

Patients who received thrombolytic therapy were more likely than those who did not to register a higher pulse rate, lower systolic blood pressure, higher respiration rate, hypothermia, hypoxemia, renal insufficiency and/or acidosis. They were also more likely to have an elevated troponin level, abnormal PCO2, higher mean or systolic pulmonary arterial pressure and/or cardiomegaly.

The American College of Chest Physicians guideline recommends against the use of thrombolytic therapy in hemodynamically uncomplicated patients with PE.

Recommendations on ICD as primary prevention for post-MI patients

A review spells out which factors to consider when deciding whether to recommend implantable cardioverter-defibrillators (ICDs) as primary prevention in high-risk patients who have had myocardial infarction.

ICDs are an established device as secondary prevention for patients who have survived a life-threatening ventricular arrhythmia. Major trials also suggest a benefit to ICD use in high-risk patients in whom life-threatening arrhythmias haven't yet occurred, but the studies' limitations make the picture less clear, the reviewer said in the Nov. 20 New England Journal of Medicine.

When selecting primary prevention patients for ICD, physicians should start by assessing ejection fraction (EF), then consider other factors, the reviewer said. Generally, those with an EF of 25% or less after MI are candidates, while those with higher than 35% EF aren't, the reviewer said. For patients with EF between 25% and 35%, studies suggest those at the lower end see more benefit than those near the top; thus additional factors in this 25%-35% EF group can tip the balance. These additional factors include:

  • Heart failure. Those with symptomatic heart failure or a history of heart failure seem more likely to benefit from an ICD, particularly in the 26%-30% group. If a patient's EF is on the borderline, a heart failure history adds support for ICD therapy.
  • QRS duration. Doctors should take into account a prolonged duration of the QRS interval (120 milliseconds or more), which studies have associated with a benefit from ICDs in the 26%-35% EF group.
  • Ventricular tachycardia (VT). Ambient nonsustained VT or VT induced by programmed electrical stimulation increase the indication for ICD in those with 26% to 35% EF.

Patients with none of the above factors can defer ICD implementation, especially if their EF is between 30%-35%. In addition, ICD isn't appropriate for patients with serious comorbidities and expected survival of one year or less. Some research suggests people age 75-plus years are just as likely to benefit as younger patients, but these patients should be in reasonably good shape both physically and mentally to be considered for ICD, the reviewer said.

Combination of psychological therapies may help patients manage diabetes

Psychological issues may interfere with type 1 diabetes management tasks such as insulin injections, diet and exercise, reported the Annals of Internal Medicine. To find out whether psychological therapy could improve diabetes management, researchers assigned 344 patients to either regular care, cognitive behavioral therapy or a combination of nurse-delivered cognitive behavioral therapy and motivational enhancement therapy (brief counseling that focuses on self-motivation). Researchers collected information on change in blood sugar levels, low blood sugar episodes, depression, quality of life, diabetes self-care activities and weight for one year. Patients who received both psychological therapies fared the best, having a greater decrease in blood sugar levels than patients who received usual care. However, the changes were small and this study cannot determine whether they would persist beyond 12 months.

Rifampin safer than standard treatment for preventing recurrent tuberculosis

While patients with latent tuberculosis infection (LTBI) are not contagious and have no symptoms, they are at risk for developing active tuberculosis at a later stage of their life, reported the Annals of Internal Medicine. Typically, LTBI is treated with nine months of daily isoniazid. However, isoniazid is associated with poor patient adherence and dangerous side-effects such as liver damage. Researchers compared adverse events and treatment completion among 847 patients receiving either nine months of isoniazid or four months of Rifampin. Researchers found that patients in the Rifampin arm had fewer serious adverse events and better adherence. Researchers believe their findings justify a large-scale trial to compare the ability of the two treatments to prevent active TB from developing.

PCI has helped reduce mortality from cardiogenic shock

Angioplasty may be reducing the incidence of cardiogenic shock by improving blood flow to the damaged heart muscle, a study in the latest Annals of Internal Medicine reports.

Researchers carefully reviewed data on more than 23,000 patients with acute coronary syndrome (ACS) in Switzerland between 1997-2006. They found that rates of cardiogenic shock on admission remained constant but the incidence of cardiogenic shock as a complication of ACS steadily decreased because fewer patients developed the condition during hospitalization. Percutaneous coronary intervention (PCI) and lipid-lowering therapy were associated with lower mortality rates among all patients with ACS.

The authors concluded that medical management, mainly PCI rates, helped lower mortality rates among patients with ACS and lower rates of cardiogenic shock development during hospitalization.