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Clinicians, providers and guideline panels use absolute effects to weigh the advantages and downsides of treatment alternatives. Relative measures have the potential to mislead readers. However, little is known about the reporting of absolute measures in systematic reviews. The objectives of our study are to determine the proportion of systematic reviews that report absolute measures of effect for the most important outcomes, and ascertain how they are analyzed, reported and interpreted. We will conduct a methodological survey of systematic reviews published in 2010. We will conduct a 1:1 stratified random sampling of Cochrane vs. non-Cochrane systematic reviews. We will calculate the proportion of systematic reviews reporting at least one absolute estimate of effect for the most patient-important outcome for the comparison of interest. We will conduct multivariable logistic regression analyses with the reporting of an absolute estimate of effect as the dependent variable and pre-specified study characteristics as the independent variables. For systematic reviews reporting an absolute estimate of effect, we will document the methods used for the analysis, reporting and interpretation of the absolute estimate. Our methodological survey will inform current practices regarding reporting of absolute estimates in systematic reviews. Our findings may influence recommendations on reporting, conduct and interpretation of absolute estimates. Our results are likely to be of interest to systematic review authors, funding agencies, clinicians, guideline developers and journal editors. Source


Alonso-Coello P.,Biomedical Research Institute Sant Pau | Zhou Q.,McMaster University | Guyatt G.,McMaster University
Thrombosis and Haemostasis | Year: 2012

Oral anticoagulation with vitamin k antagonists (VKAs) requires regular testing and dose adjustment. Home-monitoring (self-testing or self-management) is more effective than usual management. Dabigatran, does not require dose-adjustment and appears to be more effective at reducing the risk of stroke with similar risks of bleeding in patients with atrial fibrillation (AF). Dabigatran, however, has not been compared to the homemonitoring. It was the objective to evaluate the efficacy of dabigatran compared with home-monitoring of oral anticoagulation with VKAs. Randomised controlled trials (RCTs) comparing usual management of oral anticoagulation with home-monitoring, dabigatran with usual management, and RCTs comparing dabigatran with home-monitoring and including patient-important outcomes (thromboembolic events, death and major bleeding) were eligible. For our direct comparison we calculated pooled relative risks (RRs) using the Mantzel-Haenzel random effect model. For the indirect comparison we estimated lnRRs and back transformed to RR. We evaluated the quality of the evidence with the GRADE system. Dabigatran, compared with warfarin, was associated with lower rates of stroke or thromboembolism and systemic embolism but similar rates of major haemorrhage and death. Dabigatran 150 mg also increased non-significantly the rate of myocardial infarction. The quality of the evidence was high. Our indirect comparison of home-monitoring of oral anticoagulation versus dabigatran showed no convincing differences in the risk of thromboembolism, death or major bleeding. The estimates for selfmanagement vs. dabigatran showed stronger but still non-significant trends. The quality of the evidence was low. In conclusion, the indirect comparison of home monitoring of oral anticoagulation with dabigatran suggests that the treatments have similar impact on thrombosis, bleeding and death. However, the confidence in the estimate of effect is low to very low. Our analyses contrast with the available comparison of dabigatran with conventional warfarin monitoring. © Schattauer 2012. Source


Riba J.,Biomedical Research Institute Sant Pau
Drug testing and analysis | Year: 2012

Ayahuasca is an Amazonian psychotropic plant tea obtained from Banisteriopsis caapi, which contains β-carboline alkaloids, chiefly harmine, harmaline and tetrahydroharmine. The tea usually incorporates the leaves of Psychotria viridis or Diplopterys cabrerana, which are rich in N,N-dimethyltryptamine (DMT), a psychedelic 5-HT(2A/1A/2C) agonist. The β-carbolines reversibly inhibit monoamine-oxidase (MAO), effectively preventing oxidative deamination of the orally labile DMT and allowing its absorption and access to the central nervous system. Despite increased use of the tea worldwide, the metabolism and excretion of DMT and the β-carbolines has not been studied systematically in humans following ingestion of ayahuasca. In the present work, we used an analytical method involving high performance liquid chromatography (HPLC)/electrospray ionization (ESI)/selected reaction monitoring (SRM)/tandem mass spectrometry(MS/MS) to characterize the metabolism and disposition of ayahuasca alkaloids in humans. Twenty-four-hour urine samples were obtained from 10 healthy male volunteers following administration of an oral dose of encapsulated freeze-dried ayahuasca (1.0 mg DMT/kg body weight). Results showed that less than 1% of the administered DMT dose was excreted unchanged. Around 50% was recovered as indole-3-acetic acid but also as DMT-N-oxide (10%) and other MAO-independent compounds. Recovery of DMT plus metabolites reached 68%. Harmol, harmalol, and tetrahydroharmol conjugates were abundant in urine. However, recoveries of each harmala alkaloid plus its O-demethylated metabolite varied greatly between 9 and 65%. The present results show the existence in humans of alternative metabolic routes for DMT other than biotransformation by MAO. Also that O-demethylation plus conjugation is an important but probably not the only metabolic route for the harmala alkaloids in humans. Copyright © 2012 John Wiley & Sons, Ltd. Source


Martinez Garcia L.,Biomedical Research Institute Sant Pau
Implementation science : IS | Year: 2012

Scientific knowledge is in constant change. The flow of new information requires a frequent re-evaluation of the available research results. Clinical practice guidelines (CPGs) are not exempted from this phenomenon and need to be kept updated to maintain the validity of their recommendations. The objective of our review is to systematically identify, describe and assess strategies for monitoring and updating CPGs. We conducted a systematic review of studies evaluating one or more methods of updating (with or without monitoring) CPGs or recommendations. We searched MEDLINE (PubMed) and The Cochrane Methodology Register (The Cochrane Library) from 1966 to June 2012. Additionally, we hand-searched reference lists of the included studies and the Guidelines International Network book of abstracts. If necessary, we contacted study authors to obtain additional information. We included a total of eight studies. Four evaluated if CPGs were out of date, three updated CPGs, and one continuously monitored and updated CPGs. The most detailed reported phase of the process was the identification of new evidence. As opposed to studies updating guidelines, studies evaluating if CPGs were out of date applied restricted searches. Only one study compared a restricted versus an exhaustive search suggesting that a restricted search is sufficient to assess recommendations' Validity. One study analyzed the survival time of CPGs and suggested that these should be reassessed every three years. There is limited evidence about the optimal strategies for monitoring and updating clinical practice guidelines. A restricted search is likely to be sufficient to monitor new evidence and assess the need to update, however, more information is needed about the timing and type of search. Only the exhaustive search strategy has been assessed for the update of CPGs. The development and evaluation of more efficient strategies is needed to improve the timeliness and reduce the burden of maintaining the validity of CPGs. Source


Roque i Figuls M.,Biomedical Research Institute Sant Pau
Cochrane database of systematic reviews (Online) | Year: 2012

This is an update of the original Cochrane review published in 2005 and updated in 2007. Acute bronchiolitis is the leading cause of medical emergencies during winter in children younger than two years of age. Chest physiotherapy is thought to assist infants in the clearance of secretions and to decrease ventilatory effort. The main objective was to determine the efficacy of chest physiotherapy in infants aged less than 24 months old with acute bronchiolitis. A secondary objective was to determine the efficacy of different techniques of chest physiotherapy (for example, vibration and percussion and passive forced exhalation). We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4) which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to November week 3, 2011), MEDLINE in-process and other non-indexed citations (8 December 2011), EMBASE.com (1990 to December 2011), CINAHL (1982 to December 2011), LILACS (1985 to December 2011) and Web of Science (1985 to December 2011). Randomised controlled trials (RCTs) in which chest physiotherapy was compared against no intervention or against another type of physiotherapy in bronchiolitis patients younger than 24 months of age. Two review authors independently extracted data. Primary outcomes were respiratory parameters and improvement in severity of disease. Secondary outcomes were length of hospital stay, duration of oxygen supplementation and the use of bronchodilators and steroids. No pooling of data was possible. Nine clinical trials including 891 participants were included comparing physiotherapy with no intervention. Five trials (246 participants) evaluated vibration and percussion techniques and four trials (645 participants) evaluated passive expiratory techniques. We observed no significant differences in the severity of disease (eight trials, 867 participants). Results were negative for both types of physiotherapy. We observed no differences between groups in respiratory parameters (two trials, 118 participants), oxygen requirements (one trial, 50 participants), length of stay (five trials, 222 participants) or severe side effects (two trials, 595 participants). Differences in mild transient adverse effects (vomiting and respiratory instability) have been observed (one trial, 496 participants). Since the last publication of this review new good-quality evidence has appeared, strengthening the conclusions of the review. Chest physiotherapy does not improve the severity of the disease, respiratory parameters, or reduce length of hospital stay or oxygen requirements in hospitalised infants with acute bronchiolitis not on mechanical ventilation. Chest physiotherapy modalities (vibration and percussion or forced expiratory techniques) have shown equally negative results. Source

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