Rates of ischemic stroke during warfarin treatment for atrial fibrillation.

BACKGROUND AND PURPOSE: Recent evidence suggests that there may be an increased risk of ischemic stroke immediately after warfarin initiation. We examined the rate of ischemic stroke among patients with atrial fibrillation newly started on warfarin therapy. METHODS: We conducted a population-based cohort study among Ontario residents aged ≥66 years with atrial fibrillation who received warfarin between April 1, 1997, and March 31, 2010. Each patient was followed up for ≤5 years in 30-day intervals. For each interval, we determined the rate of ischemic stroke. RESULTS: After 5 years, the cumulative incidence of ischemic stroke among new users of warfarin (n=148,446) was 4.0% (n=6006). The risk was highest during the first 30 days after initiation (6.0% per person-year; 95% confidence interval, 5.5%-6.4%) compared with the remainder of follow-up (1.6% per person-year; 95% confidence interval, 1.5%-1.6%), and increased with higher baseline CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes, previous stroke) scores. Less frequent monitoring may have contributed. CONCLUSIONS: In a large cohort of older patients with atrial fibrillation, we observed the highest rate of ischemic stroke in the first 30 days after warfarin initiation. Although causation cannot be established given the observational nature of this study, our findings highlight the need for future research in this population.

Prevention of Clostridium difficile infection with Saccharomyces boulardii: a systematic review.

BACKGROUND: Clostridium difficile is a major cause of antibiotic-associated diarrhea within the hospital setting. The yeast Saccharomyces boulardii has been found to have some effect in reducing the risk of C difficile infection (CDI); however, its role in preventive therapy has yet to be firmly established. OBJECTIVE: To review the effectiveness of S boulardii in the prevention of primary and recurrent CDI. Benefit was defined as a reduction of diarrhea associated with C difficile. Risk was defined as any adverse effects of S boulardii. METHODS: A literature search in MEDLINE, EMBASE, CINAHL and the Cochrane Library was performed. Included studies were English language, randomized, double-blind placebo controlled trials evaluating S boulardii in CDI prevention. RESULTS: Four studies were reviewed. Two studies investigated the prevention of recurrence in populations that were experiencing CDI at baseline. One trial showed a reduction of relapses in patients experiencing recurrent CDI (RR=0.53; P<0.05). The other demonstrated a trend toward reduction of CDI relapse in the recurrent treatment group of patients receiving high-dose vancomycin (RR=0.33; P=0.05). Two other studies examined primary prevention of CDI in populations that had been recently prescribed antibiotics. These studies lacked the power to detect statistically significant differences. Patients on treatment experienced increased risk for thirst and constipation. CONCLUSION: S boulardii seems to be well tolerated and may be effective for secondary prevention in some specific patient populations with particular concurrent antibiotic treatment. Its role in primary prevention is poorly defined and more research is required before changes in practice are recommended.