Annals
Established in 1927 by the American College of Physicians

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15 November 2011 Annals of Internal Medicine Tip

Annals of Internal Medicine is published by the American College of Physicians on the first and third Tuesday of every month. These highlights are not intended to substitute for articles as sources of information.

1. High CHADS2 Score Associated with Complications, Death Among A-Fib Patients on Oral Anticoagulants

The CHADS2 score is a clinical prediction rule for estimating stroke risk in patients with atrial fibrillation, but the usefulness of the score in predicting risk of bleeding on anticoagulants is unknown. One point is assigned for a history of congestive heart failure, hypertension, diabetes, or being older than 75. Two points are assigned for a history of stroke or transient ischemic attack. Current patient treatment guidelines recommend warfarin for patients with a CHADS2 score of two or higher, but bleeding risk is a concern. Researchers recruited 18,113 patients to determine bleeding and survival rates in relations to CHADS2 score among A-fib patients at risk for stroke taking anticoagulants. Patients were assigned one of two blinded doses of dabigatran (150 mg and 110 mg twice daily) or open-label warfarin. The researchers found that higher CHADS2 scores were associated with increased risks for not only stroke or systemic embolism but also major and intracranial bleeding and vascular death in patients treated with oral anticoagulants. Rates of stroke or systemic embolism were lower with dabigatran, 150 mg twice daily, and rates of intracranial bleeding were lower with both dabigatran doses than with warfarin treatment, regardless of CHADS2 score.

2. Patients on Warfarin Can Safely Wait 12 Weeks Between Dose Assessments

Current guidelines recommend that patients on warfarin have a dose assessment every four weeks. Undergoing international normalized ratio (INR) monitoring every month can be a burden for patients and the health care system. Researchers studied 250 patients on long-term warfarin therapy whose dose had been unchanged for at least 6 months to determine if patients could safely extend monitoring intervals to 12 weeks. Patients were divided into two groups: assessment every 12 weeks (n=124) or assessment every four weeks (n=126). After 12 months, researchers found that a 12-week assessment interval was non-inferior to a four-week assessment interval, as the proportion of time that patients were within the target INR range did not statistically significantly differ between groups. The researchers recommend further study before widespread adoption of extended monitoring intervals in clinical practice.

3. Whole-body Vibration Shows No Benefit for Improving BMD or Bone Structure in Postmenopausal Women

Whole-body vibration (WBV), which involves standing on an oscillating platform, has been introduced as a promising new therapy for osteoporosis. In animal studies, WBV showed significant improvements in bone formation rate, bone mineral density (BMD), trabecular structure, and cortical thickness. However, these benefits have not been proven in postmenopausal women. Researchers studied 202 healthy postmenopausal women with BMD T-scores between -1.0 and -2.5 who were not taking prescription bone medications to determine whether WBV would improve bone density and structure. Participants were randomly assigned to either stand on a low-magnitude (0.3g) 90-Hz or 30-Hz WBV platform for 20 minutes daily or to serve as control participants. All participants received calcium and vitamin D. After 12 months, patients were assessed for trabecular volumetric BMD and other bone measurements. The researchers concluded that WBV at 0.3g and 90- or 30-Hz had no affect on BMD or bone structure. Therefore, WBV does not seem beneficial for preventing bone loss in postmenopausal women who receive calcium and vitamin D. supplements.