Journal watch: Recent studies of note

Recent studies of note.


Simple bedside tool helps predict mortality in heart failure patients

A risk scoring system using commonly available clinical variables offers a convenient bedside tool for stratifying risk and predicting in-hospital mortality in patients with heart failure, a study concluded.

Researchers studied data on almost 40,000 participants in the American Heart Association's Get With the Guidelines-Heart Failure (GWTG-HF) Program. Using the GWTG-HF risk scoring system, researchers found that older age, low systolic blood pressure, elevated heart rate, low serum sodium, elevated blood urea nitrogen (BUN), presence of chronic obstructive pulmonary disease and nonblack race were predictive of in-hospital mortality. Age, systolic blood pressure and BUN contributed more to the overall point score than other factors. The results were published in January's Circulation: Cardiovascular Quality and Outcomes.

The risk model is applicable to a broad spectrum of HF patients and was equally effective in patients with preserved and impaired left ventricular systolic function, the authors noted. The GWTG-HF risk score has several advantages over other HF mortality risk models, they added. It uses a contemporary cohort of population-based patients with diverse demographic characteristics and a wide range of comorbidities and includes patients regardless of left ventricular systolic function.

In addition, the GWTG-HF model includes variables that are routinely collected at time of admission, the authors added, and the score can easily be calculated at the bedside or online when data are entered into the GWTG Web-based tool.

Contraindicated drugs raise risk of bleeding in dialysis patients after PCI

More than 20% of dialysis patients undergoing PCI received a contraindicated antithrombotic drug, and those patients had a significantly higher risk of major bleeding than patients who did not receive the drugs, a study found.

Researchers analyzed data on more than 22,000 patients in the National Cardiovascular Data Registry who underwent percutaneous coronary intervention (PCI) between 2004 and 2008. Just over 22% of the patients received a contraindicated antithrombotic (either enoxaparin, eptifibatide or both) and those patients had a higher risk of in-hospital bleeding (5.6% vs. 2.9%) and death (6.5% vs. 3.9%) compared with patients who did not receive the drugs. There was a significant association with in-hospital bleeding, but not in-hospital death, in a subgroup analysis of patients matched by propensity scores. The association was particularly striking in patients undergoing PCI in the setting of acute coronary syndrome. The results appeared in the Dec. 9, 2009 Journal of the American Medical Association.

A possible reason for the use of contraindicated drugs is that enoxaparin, given either intravenously or as a subcutaneous injection without a continuous IV drip, is easier to administer than unfractionated heparin, the authors said. Eptifibatide also is often less expensive and more available than abciximab, they added.

To date, there has been a dearth of direct evidence from clinical trials regarding the use of contraindicated drugs in dialysis patients, who are often excluded from trials, the authors noted. This lack of evidence may have contributed to physicians' willingness to use the drugs despite labeling about contraindications.

Based on the findings, enoxaparin and eptifibatide should be avoided in dialysis patients in favor of non-renally cleared antithrombotic alternatives, the authors concluded. Quality improvement efforts are needed, they said, such as amending clinical pathway order sets to include consideration of renal function.

Prone positioning doesn't improve mortality for ARDS patients

Prone positioning doesn't provide a survival benefit over supine positioning in patients with moderate and severe acute respiratory distress syndrome (ARDS), according to a study in the Nov. 11, 2009 Journal of the American Medical Association.

Researchers randomly assigned 342 mechanically ventilated adults with ARDS to undergo supine or prone positioning during ventilation. Patients were drawn from 23 centers in Italy and two in Spain and were prospectively stratified into subgroups with moderate and severe hypoxemia. Those in the prone position remained so for at least 20 hours per day, either until the ARDS resolved or the study ended. In the supine group, prone positioning was used only as a rescue maneuver in cases of life-threatening hypoxemia. Mechanical ventilation was given according to a set protocol in both groups, while other interventions—such as nutrition and sedation—were not specified. The primary outcome was all-cause mortality 28 days after enrollment; mortality after six months and mortality from any cause at ICU discharge were secondary outcomes.

Mortality rates were similar among prone patients and supine patients at 28 days (31% vs. 32.8%; relative risk, 0.97; 95% CI, 0.84-1.13; P=0.72) and six months (47% vs. 52.3%; RR, 0.9; 95% CI, 0.73-1.11; P=0.33). The prone group had a significantly higher complication rate. Outcomes were similar between supine and prone patients with moderate hypoxemia at 28 days (25.5% vs. 22.5%; RR, 1.04; 95% CI, 0.89-1.22; P=0.62) and six months (42.6% vs. 43.9%; RR, 0.98; 95% CI, 0.76-1.25; P=0.85), as well as between prone and supine patients with severe hypoxemia at 28 days (37.8% vs. 46.1%; RR, 0.87; 95% CI, 0.66-1.14; P=0.31) and six months (52.7% vs. 63.2%; RR, 0.78; 95% CI, 0.53-1.14; P=0.19).

There's no apparent survival advantage to using prone positioning in patients with ARDS, though there was a favorable trend toward its use in severely hypoxemic patients, the authors said.

Risk of VTE high in middle-aged women following surgery

Middle-aged women have a higher risk of venous thromboembolism for up to three months after surgery, a study reported.

Researchers used data from the Million Women Study to determine the risk of venous thromboembolism (VTE) following different types of surgery. Compared with women who did not have surgery, women who had an inpatient operation were 70 times more likely to be admitted with VTE in the first six weeks following surgery, while women who had day surgery were 10 times more likely to develop VTE. Risks remained high for up to 12 weeks post-surgery, but peaked in the third week. Women who had hip or knee replacement or cancer surgery had the highest relative risks of developing VTE. The results were published Dec. 3, 2009 in BMJ.

The risk of VTE post-surgery remained elevated for up to a year, noted an accompanying editorial. This is important considering that most patients only receive preventive treatment for the days they are in the hospital, meaning that thromboprophylaxis often stops before the peak incidence of VTE, the editorialist said. It is also significant that day patients had increased risk, suggesting that preventive treatment should be more widely used in day case patients.

Current evidence suggests that thromboprophylaxis is needed for at least seven to 10 days for inpatients undergoing many orthopedic, general surgery and cancer surgery procedures, the editorial continued. Prolonged prophylaxis up to five weeks has also shown benefit in high-risk patients, and the current findings suggest that it should be extended for even longer periods. The editorialist urged further research on the risks of VTE and preventive treatments in a wider range of patients, including those without additional risk factors for VTE.

More infections with mechanical valve needleless connectors

Mechanical valve needleless connectors (MV-NCs) are associated with higher health care-associated, central venous catheter-related bloodstream infection rates than split septum needleless connectors (SS-NCs), a study found.

Researchers studied health care-associated bloodstream infection (HA-BSI) rates on 16 intensive care units, one oncology ward, and one whole hospital, all of which had switched from SS connectors or needles to MV-NCs. They compared bloodstream infection rates and prevention practices in the pre-MV-NC period, the MV-NC period, and the post MV-NC period. Results were published in the Dec. 15, 2009 Clinical Infectious Diseases.

The HA-BSI rate increased in all ICUs and wards when MV-NCs replaced SS-NCs, from a mean of 3.80 infections per 1,000 central venous catheter (CVC) days with SS-NCs to 6.83 infections per 1,000 CVC days with MV-NCs. In the 16 ICUs combined, the rate increased significantly with replacement of SS-NCs or needles (6.15 vs. 9.49 bloodstream infections per 1,000 CVC days; relative risk, 1.54; 95% CI, 1.37-1.74; P<0.001). Fourteen ICUs switched back to SS-NCs, and saw significant reductions in bloodstream infection rates (9.49 vs. 5.77 BSIs per CVC-days; RR, 1.65; 95% CI, 1.38-1.96; P<0.001).

MV-NCs are associated with higher bloodstream infection rates than are SS-NCs and needles, even when surveillance remains the same and prevention efforts are steady or increase, the authors concluded. As such, inferior infection control practices alone can't explain the higher infection risk with MV-NCs, they said. Possible reasons for the higher risk are that health care workers are unaware of the manufacturer's recommendations for MV-NC use, or that the impact of infection control breaches may be greater with MV-NC than SS-NC use.

Handheld devices help diagnose PE

Using mobile, handheld clinical decision-support systems in the emergency department improved diagnostic decision making and reduced unnecessary tests for patients with suspected pulmonary embolism, a study found.

Researchers conducted a cluster randomized trial in 20 emergency departments in France, which were randomly assigned to use either handheld electronic decision-support devices or posters and pocket cards showing guidelines for diagnosing pulmonary embolism (PE). Both groups improved their percentage of appropriate diagnostic workups but the increase was 19.3% higher in the handheld device group (P =0.023). Physicians assigned to mobile devices also ordered fewer inappropriate tests than those assigned to paper guidelines (P <0.001). The results appeared in the Nov. 17, 2009 Annals of Internal Medicine.

Mobile devices gave physicians real-time access to the probability of PE at each stage of the diagnostic workup, whereas physicians using paper had to search for information, the authors noted. The devices prompted physicians to assess initial pretest probability and helped them order appropriate tests, taking into account the clinical situation, availability and previous test results. Physicians using the devices were told to stop their workups after a PE diagnosis was excluded or confirmed and were less likely to stop their investigations prematurely if, for example, the patient had a positive d-dimer test result.

The authors concluded that handheld electronic decision-support systems have the potential to significantly improve decision making in the emergency department. Physician acceptance of the devices may increase as software becomes more sophisticated and efficient, predicted an accompanying editorial. For now, the findings are a promising start toward the goal of bringing evidence to practice, the editorial concluded.