Carl van Walraven

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BACKGROUND Readmissions to hospital are common, costly and often preventable. An easy-to-use index to quantify the risk of readmission or death after discharge from hospital would help clinicians identify patients who might benefit from more intensive post-discharge care. We sought to derive and validate an index to predict the risk of death or unplanned(More)
BACKGROUND Adverse events (AEs) are adverse outcomes caused by medical care. Several studies have indicated that a substantial number of patients experience AEs before or during hospitalization. However, few data describe AEs after hospital discharge. We determined the incidence, severity, preventability and ameliorability of AEs in patients discharged from(More)
CONTEXT Patients with nonvalvular atrial fibrillation (AF) have an increased risk of stroke and other vascular events. OBJECTIVE To compare the risk of vascular and bleeding events in patients with nonvalvular AF treated with vitamin K -inhibiting oral anticoagulants or acetylsalicylic acid (aspirin). DESIGN Pooled analysis of patient-level data from 6(More)
BACKGROUND The rate of stroke in atrial fibrillation (AF) depends on the presence of comorbid conditions and the use of antithrombotic therapy. Although adjusted-dose warfarin is superior to aspirin for reducing stroke in AF, the absolute risk reduction of warfarin depends on the stroke rate with aspirin. This prospective cohort study tested the predictive(More)
BACKGROUND For patients receiving therapy with oral anticoagulants (OACs), the proportion of time spent in the therapeutic range (ie, anticoagulation control) is strongly associated with bleeding and thromboembolic risk. The effect of study-level factors, especially study setting, on anticoagulation control is unknown. OBJECTIVES Describe anticoagulation(More)
BACKGROUND Readmissions to hospital are increasingly being used as an indicator of quality of care. However, this approach is valid only when we know what proportion of readmissions are avoidable. We conducted a systematic review of studies that measured the proportion of readmissions deemed avoidable. We examined how such readmissions were measured and(More)
STUDY OBJECTIVE The benefit of Advanced Cardiac Life Support (ACLS) medications during cardiac resuscitation is uncertain. The objective of this study was to determine whether the use of these medications increased resuscitation from in-hospital cardiac arrest. METHODS A prospective cohort of patients undergoing cardiac arrest in 1 of 5 academic hospitals(More)
UNLABELLED Emergency department (ED) overcrowding is a common problem. Despite a widespread belief that low hospital bed availability contributes to ED overcrowding, there are few data demonstrating this effect. OBJECTIVES To identify the effect of hospital occupancy on ED length of stay for admitted patients and patient disposition. METHODS This was an(More)
OBJECTIVES To determine the association between inhibition of serotonin reuptake by antidepressants and upper gastrointestinal bleeding. DESIGN Retrospective cohort study from population based databases. SETTING Ontario, Canada. PARTICIPANTS 317 824 elderly people observed for more than 130 000 person years. The patients started taking an(More)
OBJECTIVE Adverse events are adverse patient outcomes resulting from medical care. We performed this study to estimate the rate of adverse events and potential adverse events-errors that have a high likelihood of causing patient harm-occurring during obstetric care. METHODS This was a prospective cohort study of an obstetric unit in a teaching hospital.(More)