Continual Decrease in Blood Lead Level in Americans: United States National Health Nutrition and Examination Survey 1999-2014

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Inorganic mercury poisoning due to the use of beauty cream in Hong Kong

INTRODUCTION: Use of inorganic mercury compounds in cosmetic products is prohibited as it can cause significant nephrotoxicity. However, the public continues to have access to these illegal products in Hong Kong ...postprin

Duration of dual antiplatelet therapy after drug-eluting stent implantation: Meta-analysis of large randomised controlled trials

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Randomized controlled trial of the effect of phytosterols-enriched low-fat milk on lipid profile in Chinese

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Incentivizing research into the effectiveness of medical devices

Introduction Medical devices (MDs) often obtain market authorization with much less clinical evidence than other health technologies, especially pharmaceuticals. This is due to a number of reasons. First, in contrast to pharmaceuticals, there is no legal requirement to conduct adequately controlled clinical studies, other than for ‘high-risk’ devices in some jurisdictions. In the US for example, high-risk devices and innovative lower-risk devices are required to demonstrate ‘reasonable assurance of safety and effectiveness’, which may imply clinical evidence based on randomized studies in many instances. In contrast, in the EU the requirement is to demonstrate adequate performance and safety, which can often be achieved by conducting observational studies such as registries [1, 2]. Secondly, the devices industry comprises many small and medium-size enterprises (SMEs), which would find the cost of conducting clinical studies, especially randomized controlled trials, prohibitive. However, although some larger manufacturers do undertake clinical studies of some of their products, manufacturers with similar products (called ‘fast-followers’) can often claim ‘substantial equivalence’ to a product that already has market authorization, thus avoiding the need to conduct costly and timeconsuming clinical studies. Since regulatory agencies often accept these claims of equivalence, for example under the 510(k) process in the US [3], this further reduces the incentives for manufacturers to conduct expensive clinical studies. Therefore, although device manufacturers have patent protection, they are often not granted data exclusivity in the same way as pharmaceutical manufacturers. Finally, unlike pharmaceuticals, devices are often modified once on the market, meaning that even if clinical evidence was available for the original version of the product, it may not necessarily be available for the version currently being marketed. For example in the US, one analysis showed that for 77 original market authorization applications for cardiac implantable electronic devices (e.g., pacemakers, implantable cardioverter-defibrillators) since 1979, the FDA approved 5829 ‘supplements’ reflecting product modifications in the period up until 2012. Of course, many of these product modifications were minor and unlikely to affect the performance of the device, but 37 % involved a change to the device’s design. In the vast majority of these cases the FDA deemed that new clinical data were not necessary for approval [4]. The lack of clinical evidence prior to product launch, especially evidence of comparative effectiveness, limits the possibilities for health technology assessment [2]. However, it should be remembered that clinical evidence can be gathered both pre-market (i.e., through conducting controlled clinical trials in an experimental setting), and postmarket, through clinical studies undertaken in regular clinical practice. Post-market effectiveness research may be more important for MDs than pharmaceuticals, as the performance of the device often depends on the interaction with the user (the so-called learning curve) [5]. This suggests that solutions to the problem of inadequate clinical evidence should address the issue of conducting clinical research in both the pre- and post-market phase. In this editorial we consider ways in which MD manufacturers could be incentivized to produce more clinical evidence to facilitate health technology assessments, including economic evaluations

Optimal duration of dual antiplatelet therapy after drug-eluting stent implantation: Meta-analysis of randomized controlled trials

Objective After implantation of drug-eluting stents (DES), patients usually receive 6–12 months of dual antiplatelet therapy (DAPT). However, the optimal duration of DAPT is controversial. Therefore, we performed a meta-analysis of randomized controlled trials to assess the risks and benefits of different DAPT durations. Methods We searched the literature using MEDLINE, Scopus, EMBASE, ISI Web of Science, Cochrane Library, ClinicalTrials.gov and recent conference proceedings, and included those trials randomizing patients to receive different durations of DAPT after DES implantation and reporting frequencies of cardiovascular and bleeding events. Data from eleven trials were analyzed using RevMan. Results Compared to 12-month DAPT treatment, extended DAPT significantly reduced the frequencies of myocardial infarction (OR 0.54 95% CI: 0.43–0.66; p < 0.00001) and stent thrombosis (OR 0.36 95% CI: 0.24–0.55; p < 0.00001), but the risks of major bleeding (OR 1.54 95% CI 1.22–1.96) and all-cause mortality (OR 1.43 95% CI 1.14–1.81) were substantially increased. There was no significant difference in stroke, cardiovascular mortality or repeat revascularization. Compared to short-term DAPT, 12-month DAPT or longer was associated with increased major bleeds (OR 1.98 95% CI: 1.26–3.11). No significant differences were found in the risk of other primary outcomes. Conclusion 12-month DAPT appears to be a pragmatic compromise between preventing stent thrombosis and increasing bleeding risk. Patients at high bleeding risk should have shorter duration DAPT while those with low bleeding risk can be considered for DAPT beyond 12 months. © 2016 Elsevier Ireland Ltd.postprin

Validity and reliability of the Chinese critical thinking disposition inventory

2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe