Peter Loewen

Incidence, severity and preventability of medication-related visits to the emergency department: a prospective study

Background: Medication-related visits to the emergency department are an important but poorly understood phenomenon. We sought to evaluate the frequency, severity and preventability of drug-related visits to the emergency department. Methods: We performed a prospective observational study of randomly selected adults presenting to the emergency department over a 12-week period. Emergency department visits were identified as drug-related on the basis of assessment by a pharmacist research assistant and an emergency physician; discrepancies were adjudicated by 2 independent reviewers. Results: Among the 1017 patients included in the study, the emergency department visit was identified as drug-related for 122 patients (12.0%, 95% confidence interval [CI] 10.1%–14.2%); of these, 83 visits (68.0%, 95% CI 59.0%–76.2%) were deemed preventable. Severity was classified as mild in 15.6% of the 122 cases, moderate in 74.6% and severe in 9.8%. The most common reasons for drug-related visits were adverse drug reactions (39.3%), nonadherence (27.9%) and use of the wrong or suboptimal drug (11.5%). The probability of admission was significantly higher among patients who had a drug-related visit than among those whose visit was not drug-related (OR 2.18, 95% CI 1.46–3.27, p < 0.001), and among those admitted, the median length of stay was longer (8.0 [interquartile range 23.5] v. 5.5 [interquartile range 10.0] days, p = 0.06). Interpretation: More than 1 in 9 emergency department visits are due to drug-related adverse events, a potentially preventable problem in our health care system.

Medication-Induced Headache: Overview and Systematic Review of Therapeutic Approaches

OBJECTIVE: To review medication-induced headache (MIH) through a systematic evaluation of the literature regarding the pharmacologic management of this condition. METHODOLOGY: To identify and evaluate all pharmacologic interventions for MIH, we conducted a qualitative systematic review of the English-language literature from 1966 to June 1998 using MEDLINE. The following search terms were used: chronic daily headache, transformed migraine, analgesic withdrawal headache, analgesic rebound headache, drug-associated headache, medication-induced headache, detoxification, and dihydroergotamine. In addition, a review of the references from relevant literature was also conducted to collect reports not identified in the MEDLINE search. RESULTS: Numerous therapies for acute management of MIH have been evaluated, although no rigorously conducted clinical trials were identified. Therapies evaluated include abrupt withdrawal of analgesics, initiation of dihydroergotamine, nonsteroidal antiinflammatory agents, methylergonovine, dihydroergotamine, sumatriptan, amitriptyline, dexamethasone, piracetam, prothipendyl, and valproate. Epidemiology, diagnosis, clinical features, pathophysiology, and long-term prognosis of therapy are discussed and therapeutic guidelines are offered. CONCLUSIONS: MIH is an underrecognized and difficult condition affecting headache-prone patients. The published literature concerning treatment of patients with MIH is scant and of poor quality, making it difficult for clinicians to decide on appropriate therapy. Recognition and treatment of MIH may lead to a long-term improvement in headache relief for many patients. It appears that complete withdrawal of the medications being overused is required for favorable long-term results.

Cost-Utility Analysis of Tissue Plasminogen Activator Therapy for Acute Ischaemic Stroke A Canadian Healthcare Perspective

AbstractBackground: There are over 40 000 ischaemic strokes annually in Canada, which result in significant morbidity, mortality and burden to the healthcare system. A recent, large clinical trial has evaluated tissue plasminogen activator (t-PA) intravenously for the treatment of acute ischaemic stroke with promising outcomes but with an increased risk of symptomatic intracranial haemorrhage. Objective: To compare clinical and economic outcomes of intravenous t-PA therapy (0.9 mg/kg, to a maximum of 90mg, initiated within 3 hours of stroke onset) versus no t-PA for acute ischaemic stroke based on the outcomes achieved in the National Institute of Neurological Disorders and Stroke (NINDS) trial. Design: A Markov model depicting the natural lifetime course after an initial acute ischaemic stroke. On the basis of this model, a simulated trial compared no t-PA with t-PA. Patients: A hypothetical cohort of 1000 patients with acute ischaemic stroke. Study perspective: Canadian healthcare system. Outcome measures: Total acute stroke and post-stroke treatment costs and cumulative quality-adjusted life-years (QALYs). Results: For a hypothetical cohort of 1000 patients, the estimated lifetime stroke costs were 103 100 000 Canadian dollars (

Risk of bleeding with oral anticoagulants: an updated systematic review and performance analysis of clinical prediction rules.

Can) [1999 values) in the t-PA arm (

Losartan as an Alternative to ACE Inhibitors in Patients with Renal Dysfunction

Can103 100 per patient) compared with

Reasons for non‐use of proven pharmacotherapeutic interventions: systematic review and framework development

Can106 900 000 in the no t-PA arm (

Pharmacists' perceptions of the impact of care they provide

Can106 900 per patient), yielding a lifetime cost difference of

Learner : preceptor ratios for practice‐based learning across health disciplines: a systematic review

Can3 800 000 in favour of t-PA versus no t-PA (

Opportunities for Optimizing Pantoprazole Therapy in Patients with Acute Upper Gastrointestinal Bleeding

Can3800 per patient). In the hypothetical cohort, t-PA treatment resulted in 13 130 QALYs versus 9670 QALYs with no t-PA treatment. This translated into a net benefit of 3460 additional QALYs per 1000 patients (3.46 QALYs per patient). No treatment, outcome or economic variables influenced the model outcome. Conclusion: From the standpoint of cost effectiveness, treatment of acute ischaemic stroke with intravenous t-PA is an economically attractive strategy.

Patient preferences regarding atrial fibrillation stroke prophylaxis in patients at potential risk of atrial fibrillation

This study aimed to determine whether progress in developing bleeding risk estimation tools for patients on oral anticoagulant therapy has been made since 2006 when we last systematically reviewed this topic, and to refresh previously published quantitative evaluations of the clinical prediction rules (CPRs) available for estimating bleeding risk in patients on oral anticoagulant therapy. A systematic review of English language literature published since December 2006 was conducted when our previous systematic review ended. Studies were analyzed for predictive performance using likelihood ratios. Six studies detailed CPRs used to assess risk of bleeding prior to commencing warfarin therapy, four of which were included in the analysis. Three studies evaluated new CPRs (“RIETE” and “HAS-BLED”). One of the studies was a further validation of the modified outpatient bleeding risk index (mOBRI) in patients with atrial fibrillation. Individual trial and pooled analyses using likelihood ratios for mOBRI and HAS-BLED showed they have weak predictive accuracy. A RIETE score of 0 point was moderately predictive of the absence of major bleeding. None of the CPRs exhibited sufficient predictive accuracy or had sufficient validation to be recommended for routine use in practice. None of the available CPRs exhibit sufficient predictive accuracy or have trials evaluating the impact of their use on patient outcomes. Hence, no existing oral anticoagulation major bleeding CPR can be recommended for routine use in practice at present.