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Biomedical subjects

Yoon K Loke

Publications and source records attributed to Yoon K Loke.

8 recordsLinked to original sources

Statins and pancreatitis: a systematic review of observational studies and spontaneous case reports.

Many anecdotal reports have suggested that therapy with HMG-CoA reductase inhibitors ('statins') can cause acute pancreatitis. We aimed to quantify the association between statins and pancreatitis and to classify the adverse effect under the dose, time, susceptibility (DoTS) system. We searched for controlled observational studies that assessed the risk of pancreatitis in patients receiving statins. In order to identify case reports of statin-induced pancreatitis, we looked for reports published in scientific journals and manually reviewed reports within the Canadian Adverse Drug Event Monitoring System (CADRMP) database. Two observational studies were identified and the data pooled together in a meta-analysis. This yielded an odds ratio of 1.41 (95% CI 1.15, 1.74) for the risk of acute pancreatitis in patients with a past history of exposure to statins. We also identified 20 published case reports and 33 spontaneous reports from the CADRMP database. These data showed that pancreatitis can occur at both high and low doses, with 12 cases developing pancreatitis at less than the dose equivalent of simvastatin 20 mg daily. Statin-induced pancreatitis can occur at any time but seems to be very uncommon early on and more likely to occur after many months of therapy. There does not appear to be a cumulative dose effect and increasing age does not appear to be a major susceptibility factor. These finding should help clinicians to better manage and diagnose patients who are at risk of statin-induced pancreatitis.

Age Factors↗

A comparison of three different sources of data in assessing the frequencies of adverse reactions to amiodarone.

AIMS: To compare the frequencies of adverse drug reactions (ADRs) to amiodarone from three separate datasets: (i) a meta-analysis of clinical trials, (ii) spontaneous reports published in medical journals, and (iii) spontaneous reports sent to the World Health Organization (WHO). METHODS: We classified the ADRs into eight categories, based on the site involved, and built a rank order of the ADRs by category (from most to least commonly reported) for each dataset. We also calculated the relative proportions for all eight ADR categories within each dataset, in order to be able to compare the distributions of ADR frequencies: we assigned an index value of 1.0 to the frequency of respiratory toxicity in each set and calculated values for the other ADRs relative to respiratory toxicity. RESULTS: Thyroid disorders were the most commonly reported ADRs in the WHO dataset. In contrast, published case reports showed a preponderance of respiratory disorders, while in the meta-analysis cardiac conduction problems were the most frequent. The rank orders of ADRs differed among the three datasets, as did the index values of specific ADR categories with respect to the respiratory category. CONCLUSIONS: The distributions of ADR rank order and relative frequencies are dissimilar among the three datasets, as each dataset compiles information in a different way. Nevertheless, each dataset has its own specific strengths, and all three should be used together in obtaining a complete picture of a drug's safety profile. Important therapeutic and regulatory decisions should not simply be based on one source of data.

Adverse Drug Reaction Reporting Systems↗

Determining the reporting quality of RCTs in clinical pharmacology.

BACKGROUND: The Consolidated Standards for Reporting Trials (CONSORT) are recommendations for improving the quality of reports of randomized controlled trials (RCTs). OBJECTIVE: To determine the extent to which clinical pharmacology journals implement specific CONSORT recommendations. DESIGN AND SETTING: Analysis of RCTs published between May 2002 and May 2003 in four clinical pharmacology journals. MAIN OUTCOME MEASURES: Proportion of RCTs that published a participant flow diagram and that reported on randomization and restriction methods, allocation concealment, blinding, intention-to-treat analysis, ethical considerations, adverse events and source of funding. RESULTS: Of 482 clinical trials, 193 were RCTs. Healthy participants were involved in 129 [66.8%, 95% confidence interval (CI) 59.9, 73.1] trials, patients who required treatment in 61 (31.6%, 95% CI 25.4, 38.4) trials and both in three (1.6%, 95% CI 0.5, 4.4) trials. The following items were infrequently reported: sequence generation (17%), allocation concealment (3%), use of restriction (16%), description of blinding (26%), and flow diagrams of study participants (2%). In contrast, the following areas were often reported: use of intention-to-treat analysis (79%), description of withdrawals (92.2%) and description of adverse events (71%), ethics review (94%) and informed consent (95%). Sources of funding were reported in 56% of studies. CONCLUSION: The use of the selected CONSORT items is limited in these journals, possibly as many items may not be relevant to the types of studies published in clinical pharmacology journals. Further efforts are required to determine the applicability of CONSORT to RCTs in clinical pharmacology.

Humans↗

Does anybody read "evidence-based" articles?

BACKGROUND: The electronic version of the British Medical Journal (eBMJ) has a unique feature in that it provides an electronic record of the number of times an article has been viewed ("hits") in the week after its publication. We sought to compare the relative popularity of primary research and "evidence-based" papers against that of narrative reviews and editorials. We surveyed four broad groupings of articles in 2001: Editorials, Clinical Reviews (which are narrative reviews), Education and Debate, and Papers (which are original research articles and systematic reviews). Clinical Reviews were the most frequently viewed articles, with an average of 4148 hits per article, while Papers were less popular (average of 1168 hits per article). Systematic reviews (23 articles, average of 1190 hits per article) were visited far less often than narrative reviews. Editorials (average of 2537 hits per article) were viewed much more frequently than Papers, even where the editorial was written as an accompanying piece with a direct link to the paper. DISCUSSION: Narrative reviews and editorials are accessed more frequently than primary research papers or systematic reviews in the first week after their publication. These findings may disappoint those who believe that it is important for readers to critically appraise the primary research data. Although the technical quality of journal articles may have been helped by recommendations on structured reporting, the readability of such articles has received little attention. Authors and journal editors must take steps to make research articles and systematic reviews more attractive to readers. This may involve using simpler language, as well as innovative use of web resources to produce shorter, snappier papers, with the methodological or technical details made available elsewhere. CONCLUSION: Primary research and "evidence-based" papers seem to be less attractive to readers than narrative reviews and editorials in the first week after publication. Authors and editors should try to improve the early appeal of primary research papers.

Evidence-Based Medicine↗

Air travel and venous thrombosis: how much help might aspirin be?

There has been considerable attention focused recently on the risk of deep venous thrombosis (DVT) associated with air travel. Despite the lack of evidence among air travelers, a single dose of aspirin has been widely recommended as a means of preventing such thrombosis. We have calculated the potential benefit of aspirin by applying the data for aspirin in preventing DVT in hip fracture patients to the estimated rates of travel-related DVT. If the rate of travel-related DVT is 20 per 100,000 travelers, then we will have to treat 17,000 people with aspirin to prevent 1 additional DVT.

Adult↗

Appetite suppressants and valvular heart disease - a systematic review.

BACKGROUND: Although appetite suppressants have been implicated in the development of valvular heart disease, the exact level of risk is still uncertain. Initial studies suggested that as many as 1 in 3 exposed patients were affected, but subsequent research has yielded substantially different figures. Our objective was to systematically assess the risk of valvular heart disease with appetite suppressants. METHODS: We accepted studies involving obese patients treated with any of the following appetite suppressants: fenfluramine, dexfenfluramine, and phentermine. Three types of studies were reviewed: controlled and uncontrolled observational studies, and randomized controlled trials. Outcomes of interest were echocardiographically detectable aortic regurgitation of mild or greater severity, or mitral regurgitation of moderate or greater severity. RESULTS: Of the 1279 patients evaluated in seven uncontrolled cohort studies, 236 (18%) and 60 (5%) were found to have aortic and mitral regurgitation, respectively. Pooled data from six controlled cohort studies yielded, for aortic regurgitation, a relative risk ratio of 2.32 (95% confidence intervals 1.79 to 3.01, p < 0.00001) and an attributable rate of 4.9%, and for mitral regurgitation, a relative risk ratio of 1.55 (95% confidence intervals 1.06 to 2.25, p = 0.02) with an attributable rate of 1.0%. Only one case of valvular heart disease was detected in 57 randomized controlled trials, but this was judged unrelated to drug therapy. CONCLUSIONS: The risk of valvular heart disease is significantly increased by the appetite suppressants reviewed here. Nevertheless, when considering all the evidence, valvulopathy is much less common than suggested by the initial, less methodologically rigorous studies.

Appetite Depressants↗

Adverse drug reactions: keeping up to date.

The amount of published literature on adverse drug reactions is overwhelming; for example, the serial publication Side Effects of Drugs Annual lists and critically discusses over 3000 references each year. As a group, pharmacotherapeutics journals publish more papers on adverse drug reactions than journals that cover other fields, but even so they publish a minority of the total number of papers, and no single journal or group of journals can be highlighted as being a frequent source of primary information. Non-specialists must therefore rely on secondary literature (reviews) and tertiary literature (critical summaries) for information. Most of the primary published literature is in the form of anecdotal reports (30%) and formal studies or randomized controlled trials (35%). The anecdotal reports vary in quality; a new serial publication devoted to this type of article would bring some of the literature together and would improve the quality of reporting. Although many of the randomized controlled trials are of good quality and large enough to reveal benefit, most are too small to provide robust information about adverse drug reactions. Systematic reviews are too few in number (only 1.25% of publications on adverse drug reactions cited in Side Effects of Drugs Annual); more are needed.

Adverse Drug Reaction Reporting Systems↗