Background: Clinical guidelines recommend beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers, and statins for the secondary prevention of acute myocardial infarction (AMI). It is not clear whether variation in real-world practice reflects poor quality-of-care or a balance of outcome tradeoffs across patients. Methods: The study cohort included Medicare fee-for-service beneficiaries hospitalized 2007-2008 for AMI. Treatment within 30-days post-discharge was grouped into one of eight possible combinations for the three drug classes. Outcomes included one-year overall survival, one-year cardiovascular-event-free survival, and 90-day adverse events. Treatment effects were estimated using an Instrumental Variables (IV) approach with instruments based on measures of local-area practice style. Pre-specified data elements were abstracted from hospital medical records for a stratified, random sample to create \"unmeasured confounders\" (per claims data) and assess model assumptions. Results: Each drug combination was observed in the final sample (N = 124,695), with 35.7% having all three, and 13.5% having none. Higher rates of guideline-recommended treatment were associated with both better survival and more adverse events. Unmeasured confounders were not associated with instrumental variable values. Conclusions: The results from this study suggest that providers consider both treatment benefits and harms in patients with AMIs. The investigation of estimator assumptions support the validity of the estimates.

No guidelines have been published regarding stereotactic radiosurgery (SRS) in the management of Spetzler-Martin grade I and II arteriovenous malformations (AVMs).
To establish SRS practice guidelines for grade I-II AVMs on the basis of a systematic literature review.
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant search of Medline, Embase, and Scopus, 1986-2018, for publications reporting post-SRS outcomes in ≥10 grade I-II AVMs with a follow-up of ≥24 mo. Primary endpoints were obliteration and hemorrhage; secondary outcomes included Spetzler-Martin parameters, dosimetric variables, and \"excellent\" outcomes (defined as total obliteration without new post-SRS deficit).
Of 447 abstracts screened, 8 were included (n = 1, level 2 evidence; n = 7, level 4 evidence), representing 1102 AVMs, of which 836 (76%) were grade II. Obliteration was achieved in 884 (80%) at a median of 37 mo; 66 hemorrhages (6%) occurred during a median follow-up of 68 mo. Total obliteration without hemorrhage was achieved in 78%. Of 836 grade II AVMs, Spetzler-Martin parameters were reported in 680: 377 were eloquent brain and 178 had deep venous drainage, totaling 555/680 (82%) high-risk SRS-treated grade II AVMs.
The literature regarding SRS for grade I-II AVM is low quality, limiting interpretation. Cautiously, we observed that SRS appears to be a safe, effective treatment for grade I-II AVM and may be considered a front-line treatment, particularly for lesions in deep or eloquent locations. Preceding publications may be influenced by selection bias, with favorable AVMs undergoing resection, whereas those at increased risk of complications and nonobliteration are disproportionately referred for SRS.

In this paper, we discuss the consensus problem of non-linear multi-agent systems where an impulsive protocol with event-based asynchronously sampled data is adopted. Systems that communicate by data asynchronously sampled in limited time intervals are constructed. By separating time instants at which the sampling and communication occur into different ones, resources for such activations that every agent must execute can be reallocated to reduce the system load at communication instants. Event-based schemes are introduced to manipulate the sampling behavior. Two cases that with and without leader in directed networks topologies are both investigated. Sufficient conditions for system parameters and the event-based sampling schemes are given to guarantee the consensus. Numerical simulations are presented to illustrate the effectiveness of our proposed method.

Clinical practice guidelines abound. The recommendations contained in these guidelines are used not only to make decisions about the care of individual patients but also as practice standards to rate physician \"quality.\" Physicians\' confidence in guidelines is based on the supposition that there is a rigorous, objective process for developing recommendations based on the best available evidence. Though voluntary standards for the development of guidelines exist, the process of guideline development is unregulated and the quality of many guidelines is low. In addition, the few tools available to assess the quality of guidelines are time consuming and designed for researchers, not clinicians. Few guidelines are evaluated, either before or after their dissemination, for their impact on patient outcomes. Just as with pharmaceuticals and other products that can affect patients for better or worse, perhaps it is time to develop more standardized ways to evaluate the development and dissemination of clinical practice guidelines to ensure a similar balance between risk and benefit.

Clinical and population research on dementia and related neurologic conditions, including Alzheimer\'s disease, faces several unique methodological challenges. Progress to identify preventive and therapeutic strategies rests on valid and rigorous analytic approaches, but the research literature reflects little consensus on \"best practices.\" We present findings from a large scientific working group on research methods for clinical and population studies of dementia, which identified five categories of methodological challenges as follows: (1) attrition/sample selection, including selective survival; (2) measurement, including uncertainty in diagnostic criteria, measurement error in neuropsychological assessments, and practice or retest effects; (3) specification of longitudinal models when participants are followed for months, years, or even decades; (4) time-varying measurements; and (5) high-dimensional data. We explain why each challenge is important in dementia research and how it could compromise the translation of research findings into effective prevention or care strategies. We advance a checklist of potential sources of bias that should be routinely addressed when reporting dementia research.

OBJECTIVE: To create guidelines for randomized controlled trials (RCTs) investigating interventions used in the management of vitiligo.
METHODS: Guideline developers included authors (clinicians, patient representatives, and a statistician) of the Cochrane systematic review \"Interventions for Vitiligo\" plus the coordinator of the vitiligo priority-setting partnership at the Centre of Evidence-Based Dermatology at the University of Nottingham.
METHODS: The guidelines are based on the assessment of the quality of design and reporting of RCTs evaluating interventions for vitiligo included in the 2010 update of the Cochrane systematic review \"Interventions for Vitiligo.\"
METHODS: We reviewed and commented on the sources of bias in existing RCTs on interventions for vitiligo (selection bias, blinding assessment, attrition bias, characteristics of participants, interventions, and outcomes) based on the findings of the Cochrane review, and we used open discussion on guideline drafts focusing on the study question (participants, interventions, and outcomes), study design (research methods), and reporting.
CONCLUSIONS: Much opportunity exists for improving the design and reporting of vitiligo clinical trials. The proposed guidelines will help overcome methodologic challenges faced when conducting RCTs to answer treatment questions.

暂无摘要。

The diagnostic gold standard for food allergy is challenge with the culprit food, particularly in double-blind placebo-controlled challenge. This approach involves risks and consumes both time and resources. A more efficient system would be desirable. The detection of serum specific immunoglobulin E (sIgE) against the culprit food enables us to establish sensitization, although this is not always accompanied by clinical reactivity. Age, symptoms (immediate/late reaction, local/systemic reaction), concomitant condition (eg, atopic dermatitis, pollinosis) and selection sample criteria (eg, presence of symptoms related to ingestion, positive skin prick test result) can influence the detection and concentration of IgE against foods. We analyze the clinical usefulness of sIgE determination in light of studies in which oral food challenge is used as the diagnostic method. We review clinical usefulness at diagnosis and in the decision to reintroduce the food, as well as the prognostic value of the determination of IgE to foods.

OBJECTIVE: Health-state changes can lead to response shifts in internal standards. The most commonly used method for detecting such recalibration response shift is the retrospective pretest-posttest design, here referred to as thentest. Since this design faces significant problems, there is a pressing need to improve the stringency of studies using the thentest approach. Our objective is to provide guidelines for the optimal use of the thentest approach for detecting recalibration response shift.
METHODS: Discussion of methods based on relevant literature.
RESULTS: A checklist is provided that includes recommendations for studies using the thentest approach focusing on: (1) designing the study; (2) formulating hypotheses; (3) constructing the thentest; (4) identifying change; (6) taking alternative explanations into account; (7) using analytic standards; and (8) interpreting results.
CONCLUSIONS: The guidelines-checklist has the potential to stimulate rigorous and replicable research using the thentest. This checklist might also be of use for journal editors and reviewers as \'gate keepers\' of stringent research. Many of these suggestions also apply to other methods of detecting response shift.

BACKGROUND: Poor reporting compromises the reliability and clinical value of prognostic tumour marker studies. We review articles to assess the reporting of patients and events using REMARK guidelines, at the time of guideline publication.
METHODS: We sampled 50 prognostic tumour marker studies from higher impact cancer journals between 2006 and 2007. The inclusion criteria were cancer; focus on single biological tumour marker; survival analysis; multivariable analysis; and not gene array or proteomic data. Articles were assessed for the REMARK profile and other REMARK guideline items. We propose a reporting aid, the REMARK profile, motivated by the CONSORT flowchart.
RESULTS: In 50 studies assessed for the REMARK profile, the number of eligible patients (56% of articles), excluded patients (54%) and patients in analyses (98%) was reported. Only 50% of articles reported the number of outcome events. In multivariable analyses, 54% and 30% of articles reported patient and event numbers for all variables. Of the studies, 66% used archival samples, indicating a potentially biased patient selection. Only 36% of studies reported clearly defined outcomes.
CONCLUSIONS: Good reporting is critical for the interpretability and clinical applicability of prognostic studies. Current reporting of key information, such as the number of outcome events in all patients and subgroups, is poor. Use of the REMARK profile would greatly improve reporting and enhance prognostic research.