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2.
J Clin Epidemiol ; 125: 16-25, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32416338

RESUMO

BACKGROUND AND OBJECTIVE: Randomized trials included in meta-analyses are often affected by bias caused by methodological flaws or limitations, but the degree of bias is unknown. Two proposed methods adjust the trial results for bias using empirical evidence from published meta-epidemiological studies or expert opinion. METHODS: We investigated agreement between data-based and opinion-based approaches to assessing bias in each of four domains: sequence generation, allocation concealment, blinding, and incomplete outcome data. From each sampled meta-analysis, a pair of trials with the highest and lowest empirical model-based bias estimates was selected. Independent assessors were asked which trial within each pair was judged more biased on the basis of detailed trial design summaries. RESULTS: Assessors judged trials to be equally biased in 68% of pairs evaluated. When assessors judged one trial as more biased, the proportion of judgments agreeing with the model-based ranking was highest for allocation concealment (79%) and blinding (79%) and lower for sequence generation (59%) and incomplete outcome data (56%). CONCLUSION: Most trial pairs found to be discrepant empirically were judged to be equally biased by assessors. We found moderate agreement between opinion and data-based evidence in pairs where assessors ranked one trial as more biased.

3.
BMJ ; 368: l6802, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964641

RESUMO

OBJECTIVES: To study the impact of blinding on estimated treatment effects, and their variation between trials; differentiating between blinding of patients, healthcare providers, and observers; detection bias and performance bias; and types of outcome (the MetaBLIND study). DESIGN: Meta-epidemiological study. DATA SOURCE: Cochrane Database of Systematic Reviews (2013-14). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Meta-analyses with both blinded and non-blinded trials on any topic. REVIEW METHODS: Blinding status was retrieved from trial publications and authors, and results retrieved automatically from the Cochrane Database of Systematic Reviews. Bayesian hierarchical models estimated the average ratio of odds ratios (ROR), and estimated the increases in heterogeneity between trials, for non-blinded trials (or of unclear status) versus blinded trials. Secondary analyses adjusted for adequacy of concealment of allocation, attrition, and trial size, and explored the association between outcome subjectivity (high, moderate, low) and average bias. An ROR lower than 1 indicated exaggerated effect estimates in trials without blinding. RESULTS: The study included 142 meta-analyses (1153 trials). The ROR for lack of blinding of patients was 0.91 (95% credible interval 0.61 to 1.34) in 18 meta-analyses with patient reported outcomes, and 0.98 (0.69 to 1.39) in 14 meta-analyses with outcomes reported by blinded observers. The ROR for lack of blinding of healthcare providers was 1.01 (0.84 to 1.19) in 29 meta-analyses with healthcare provider decision outcomes (eg, readmissions), and 0.97 (0.64 to 1.45) in 13 meta-analyses with outcomes reported by blinded patients or observers. The ROR for lack of blinding of observers was 1.01 (0.86 to 1.18) in 46 meta-analyses with subjective observer reported outcomes, with no clear impact of degree of subjectivity. Information was insufficient to determine whether lack of blinding was associated with increased heterogeneity between trials. The ROR for trials not reported as double blind versus those that were double blind was 1.02 (0.90 to 1.13) in 74 meta-analyses. CONCLUSION: No evidence was found for an average difference in estimated treatment effect between trials with and without blinded patients, healthcare providers, or outcome assessors. These results could reflect that blinding is less important than often believed or meta-epidemiological study limitations, such as residual confounding or imprecision. At this stage, replication of this study is suggested and blinding should remain a methodological safeguard in trials.


Assuntos
Ensaios Clínicos como Assunto , Projetos de Pesquisa Epidemiológica , Avaliação de Resultados em Cuidados de Saúde , Ensaios Clínicos como Assunto/métodos , Ensaios Clínicos como Assunto/organização & administração , Ensaios Clínicos como Assunto/normas , Humanos , Variações Dependentes do Observador , Avaliação de Resultados em Cuidados de Saúde/métodos , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Projetos de Pesquisa/normas
4.
Int J Epidemiol ; 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31993631

RESUMO

BACKGROUND: Systematic reviews of prenatal alcohol exposure effects generally only include conventional observational studies. However, estimates from such studies are prone to confounding and other biases. OBJECTIVES: To systematically review the evidence on the effects of prenatal alcohol exposure from randomized controlled trials (RCTs) and observational designs using alternative analytical approaches to improve causal inference. SEARCH STRATEGY: Medline, Embase, Web of Science, PsychINFO from inception to 21 June 2018. Manual searches of reference lists of retrieved papers. SELECTION CRITERIA: RCTs of interventions to stop/reduce drinking in pregnancy and observational studies using alternative analytical methods (quasi-experimental studies e.g. Mendelian randomization and natural experiments, negative control comparisons) to determine the causal effects of prenatal alcohol exposure on pregnancy and longer-term offspring outcomes in human studies. DATA COLLECTION AND ANALYSIS: One reviewer extracted data and another checked extracted data. Risk of bias was assessed using customized risk of bias tools. A narrative synthesis of findings was carried out and a meta-analysis for one outcome. MAIN RESULTS: Twenty-three studies were included, representing five types of study design, including 1 RCT, 9 Mendelian randomization and 7 natural experiment studies, and reporting on over 30 outcomes. One study design-outcome combination included enough independent results to meta-analyse. Based on evidence from several studies, we found a likely causal detrimental role of prenatal alcohol exposure on cognitive outcomes, and weaker evidence for a role in low birthweight. CONCLUSION: None of the included studies was judged to be at low risk of bias in all domains, results should therefore be interpreted with caution. SYSTEMATIC REVIEW REGISTRATION: This study is registered with PROSPERO, registration number CRD42015015941.

5.
Environ Sci Pollut Res Int ; 27(4): 4089-4103, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31828708

RESUMO

The purpose of this study was to examine the accumulation potential of spontaneously developed Tussilago farfara populations colonizing sites with different levels of anthropogenic pollution. Physical characteristics of the soil are presented, together with the concentrations of macroelements and microelements (Ca, Mg, Fe, S, Al, Pb, Zn, Cu, Cd, Mn, As, Sb, Ag, Ti, and Sr) in both soil and plants. The biological concentration, accumulation, and translocation factors were used to assess the potential for heavy metal accumulation. Considerable differences were found among assessions from unevenly contaminated habitats, particularly in comparison with an unpolluted site. In line with the ore's characteristics, substrate samples from polluted sites were heavily contaminated with Pb, Zn, As, and Sb. Increased levels of microelements were also detected in plant samples from flotation tailings. Despite active absorption of Zn, Cu, Cd, Mn, and Sr by the plants from mining sites, the detected quantities of these elements in all samples were below the hyperaccumulation threshold. However, the obtained results indicate that the use of T. farfara from such sites in traditional medicine could pose a risk to human health due to accumulation of several toxic elements in the plant's aboveground tissues. Additionally, as a successful primary colonizer and stabilizer of technogenic substrates, T. farfara has an important role in the initial phases of revegetation of highly contaminated sites.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Oligoelementos/análise , Tussilago/química , Sérvia , Solo/química
6.
Eur J Cardiothorac Surg ; 57(1): 8-17, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31209468

RESUMO

Limited uptake of minimally invasive surgery (MIS) of the aorta hinders assessment of its efficacy compared to median sternotomy (MS). The objective of this systematic review is to compare operative and perioperative outcomes for MIS versus MS. Online databases Medline, EMBASE, Cochrane Library and Web of Science were searched from inception until July 2018. Both randomized and observational studies of patients undergoing aortic root, ascending aorta or aortic arch surgery by MIS versus MS were eligible for inclusion. Primary outcomes were 30-day mortality, reoperation for bleeding, perioperative renal impairment and neurological events. Intraoperative and postoperative timing measures were also evaluated. Thirteen observational studies were included comparing 1101 MIS and 1405 MS patients. The overall quality of evidence was very low for all outcomes. Mortality and the incidence of stroke were similar between the 2 cohorts. Meta-analysis demonstrated increased length of cardiopulmonary bypass (CPB) time for patients undergoing MS [standardized mean difference 0.36, 95% confidence interval (CI) 0.15-0.58; P = 0.001]. Patients receiving MS spent more time in hospital (standardized mean difference 0.30, 95% CI 0.17-0.43; P < 0.001) and intensive care (standardized mean difference 0.17, 95% CI 0.06-0.27; P < 0.001). Reoperation for bleeding (risk ratio 1.51, 95% CI 1.06-2.17; P = 0.024) and renal impairment (risk ratio 1.97, 95% CI 1.12-3.46; P = 0.019) were also greater for MS patients. There was substantial heterogeneity in meta-analyses for CPB and aortic cross-clamp timing outcomes. MIS may be associated with improved early clinical outcomes compared to MS, but the quality of the evidence is very low. Randomized evidence is needed to confirm these findings.

7.
Res Synth Methods ; 11(2): 260-274, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31851427

RESUMO

Randomized clinical trials underpin evidence-based clinical practice, but flaws in their conduct may lead to biased estimates of intervention effects and hence invalid treatment recommendations. The main approach to the empirical study of bias is to collate a number of meta-analyses and, within each, compare the results of trials with and without a methodological characteristic such as blinding of participants and health professionals. Estimated within-meta-analysis differences are combined across meta-analyses, leading to an estimate of mean bias. Such "meta-epidemiological" studies are published in increasing numbers and have the potential to inform trial design, assessment of risk of bias, and reporting guidelines. However, their interpretation is complicated by issues of confounding, imprecision, and applicability. We developed a guide for interpreting meta-epidemiological studies, illustrated using MetaBLIND, a large study on the impact of blinding. Applying generally accepted principles of research methodology to meta-epidemiology, we framed 10 questions covering the main issues to consider when interpreting results of such studies, including risk of systematic error, risk of random error, issues related to heterogeneity, and theoretical plausibility. We suggest that readers of a meta-epidemiological study reflect comprehensively on the research question posed in the study, whether an experimental intervention was unequivocally identified for all included trials, the risk of misclassification of the trial characteristic, and the risk of confounding, i.e the adequacy of any adjustment for the likely confounders. We hope that our guide to interpretation of results of meta-epidemiological studies is helpful for readers of such studies.

8.
BMJ ; 366: l5221, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31533922

RESUMO

OBJECTIVE: To examine the design characteristics, risk of bias, and reporting adequacy of pivotal randomised controlled trials of cancer drugs approved by the European Medicines Agency (EMA). DESIGN: Cross sectional analysis. SETTING: European regulatory documents, clinical trial registry records, protocols, journal publications, and supplementary appendices. ELIGIBILITY CRITERIA: Pivotal randomised controlled trials of new cancer drugs approved by the EMA between 2014 and 2016. MAIN OUTCOME MEASURES: Study design characteristics (randomisation, comparators, and endpoints); risk of bias using the revised Cochrane tool (bias arising from the randomisation process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result); and reporting adequacy (completeness and consistency of information in trial protocols, publications, supplementary appendices, clinical trial registry records, and regulatory documents). RESULTS: Between 2014 and 2016, the EMA approved 32 new cancer drugs on the basis of 54 pivotal studies. Of these, 41 (76%) were randomised controlled trials and 13 (24%) were either non-randomised studies or single arm studies. 39/41 randomised controlled trials had available publications and were included in our study. Only 10 randomised controlled trials (26%) measured overall survival as either a primary or coprimary endpoint, with the remaining trials evaluating surrogate measures such as progression free survival and response rates. Overall, 19 randomised controlled trials (49%) were judged to be at high risk of bias for their primary outcome. Concerns about missing outcome data (n=10) and measurement of the outcome (n=7) were the most common domains leading to high risk of bias judgments. Fewer randomised controlled trials that evaluated overall survival as the primary endpoint were at high risk of bias than those that evaluated surrogate efficacy endpoints (2/10 (20%) v 16/29 (55%), respectively). When information available in regulatory documents and the scientific literature was considered separately, overall risk of bias judgments differed for eight randomised controlled trials (21%), which reflects reporting inadequacies in both sources of information. Regulators identified additional deficits beyond the domains captured in risk of bias assessments for 10 drugs (31%). These deficits included magnitude of clinical benefit, inappropriate comparators, and non-preferred study endpoints, which were not disclosed as limitations in scientific publications. CONCLUSIONS: Most pivotal studies forming the basis of EMA approval of new cancer drugs between 2014 and 2016 were randomised controlled trials. However, almost half of these were judged to be at high risk of bias based on their design, conduct, or analysis, some of which might be unavoidable because of the complexity of cancer trials. Regulatory documents and the scientific literature had gaps in their reporting. Journal publications did not acknowledge the key limitations of the available evidence identified in regulatory documents.


Assuntos
Antineoplásicos/uso terapêutico , Aprovação de Drogas/métodos , Neoplasias/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Viés , Estudos Transversais , Controle de Medicamentos e Entorpecentes , Humanos , Projetos de Pesquisa , Relatório de Pesquisa
10.
MDM Policy Pract ; 4(2): 2381468319866828, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31453363

RESUMO

Objectives. Determine the optimal, licensed, first-line anticoagulant for prevention of ischemic stroke in patients with non-valvular atrial fibrillation (AF) in England and Wales from the UK National Health Service (NHS) perspective and estimate value to decision making of further research. Methods. We developed a cost-effectiveness model to compare warfarin (international normalized ratio target range 2-3) with directly acting (or non-vitamin K antagonist) oral anticoagulants (DOACs) apixaban 5 mg, dabigatran 150 mg, edoxaban 60 mg, and rivaroxaban 20 mg, over 30 years post treatment initiation. In addition to death, the 17-state Markov model included the events stroke, bleed, myocardial infarction, and intracranial hemorrhage. Input parameters were informed by systematic literature reviews and network meta-analysis. Expected value of perfect information (EVPI) and expected value of partial perfect information (EVPPI) were estimated to provide an upper bound on value of further research. Results. At willingness-to-pay threshold £20,000, all DOACs have positive expected incremental net benefit compared to warfarin, suggesting they are likely cost-effective. Apixaban has highest expected incremental net benefit (£7533), followed by dabigatran (£6365), rivaroxaban (£5279), and edoxaban (£5212). There was considerable uncertainty as to the optimal DOAC, with the probability apixaban has highest net benefit only 60%. Total estimated population EVPI was £17.94 million (17.85 million, 18.03 million), with relative effect between apixaban versus dabigatran making the largest contribution with EVPPI of £7.95 million (7.66 million, 8.24 million). Conclusions. At willingness-to-pay threshold £20,000, all DOACs have higher expected net benefit than warfarin but there is considerable uncertainty between the DOACs. Apixaban had the highest expected net benefit and greatest probability of having highest net benefit, but there is considerable uncertainty between DOACs. A head-to-head apixaban versus dabigatran trial may be of value.

11.
Recenti Prog Med ; 109(9): 421-431, 2018 Sep.
Artigo em Italiano | MEDLINE | ID: mdl-30303184

RESUMO

OBJECTIVE: To develop ROBIS, a new tool for assessing the risk of bias in systematic reviews (rather than in primary studies). STUDY DESIGN AND SETTING: We used four-stage approach to develop ROBIS: define the scope, review the evidence base, hold a face-to-face meeting, and refine the tool through piloting. RESULTS: ROBIS is currently aimed at four broad categories of reviews mainly within health care settings: interventions, diagnosis, prognosis, and etiology. The target audience of ROBIS is primarily guideline developers, authors of overviews of systematic reviews ("reviews of reviews"), and review authors who might want to assess or avoid risk of bias in their reviews. The tool is completed in three phases: 1) assess relevance (optional), 2) identify concerns with the review process, and 3) judge risk of bias. Phase 2 covers four domains through which bias may be introduced into a systematic review: 1) study eligibility criteria; 2) identification and selection of studies; 3) data collection and study appraisal; and 4) synthesis and findings. Phase 3 assesses the overall risk of bias in the interpretation of review findings and whether this considered limitations identified in any of the phase 2 domains. Signaling questions are included to help judge concerns with the review process (phase 2) and the overall risk of bias in the review (phase 3); these questions flag aspects of review design related to the potential for bias and aim to help assessors judge risk of bias in the review process, results, and conclusions. CONCLUSIONS: ROBIS is the first rigorously developed tool designed specifically to assess the risk of bias in systematic reviews.


Assuntos
Viés , Literatura de Revisão como Assunto , Medição de Risco/métodos , Humanos , Projetos Piloto , Projetos de Pesquisa/normas
14.
BMC Psychiatry ; 18(1): 275, 2018 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-30176844

RESUMO

BACKGROUND: There is conflicting evidence on the association between antipsychotic polypharmacy and metabolic syndrome in schizophrenia. We conducted a review of published systematic reviews to evaluate evidence on the association between metabolic syndrome (diabetes, hypertension, and hyperlipidaemia) and exposure to antipsychotic polypharmacy in schizophrenia. METHODS: We searched five electronic databases, complemented by reference screening, to find systematic reviews that investigated the association of antipsychotic polypharmacy in schizophrenia with hypertension, diabetes, or hyperlipidaemia. Selection of reviews, data extraction and review quality were conducted independently by two people and disagreements resolved by discussion. Results were synthesised narratively. RESULTS: We included 12 systematic reviews, which reported heterogeneous results, mostly with narrative syntheses and without pooled data. The evidence was rated as low quality. There was some indication of a possible protective effect of drug combinations including aripiprazole for diabetes and hyperlipidaemias, compared to other combinations and/or monotherapy. Only one review reported the association between APP and hypertension. The most frequently reported combinations of medication included clozapine, possibly representing a sample of patients with treatment resistant illness. No included review reported results separately by setting (primary or secondary care). CONCLUSIONS: Further robust studies are needed to elucidate the possible protective effect of aripiprazole. Long-term prospective studies are required for accurate appraisal of diabetes risk, hypertension and hyperlipidaemia in patients exposed to antipsychotic polypharmacy.


Assuntos
Antipsicóticos/uso terapêutico , Síndrome Metabólica/etiologia , Polimedicação , Esquizofrenia/tratamento farmacológico , Adulto , Antipsicóticos/efeitos adversos , Aripiprazol/uso terapêutico , Clozapina/uso terapêutico , Quimioterapia Combinada , Feminino , Humanos , Masculino , Síndrome Metabólica/tratamento farmacológico , Pessoa de Meia-Idade , Estudos Prospectivos , Esquizofrenia/metabolismo , Revisões Sistemáticas como Assunto
16.
BMJ Open ; 8(1): e015538, 2018 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-29358414

RESUMO

OBJECTIVES: To evaluate the association between the quality of relationship between a person with dementia and their family carer and outcomes for the person with dementia. DESIGN: Systematic review. ELIGIBILITY CRITERIA: Cohort studies of people with clinically diagnosed dementia and their main carers. Exposures of interest were any elements of relationship quality, for example, attachment style, expressed emotion and coping style. Our primary outcome was institutionalisation, and secondary outcomes were hospitalisation, death, quality of life and behavioural and psychiatric symptoms of dementia ('challenging behaviour'). DATA SOURCES: MEDLINE, Embase, Web of Science, PsycInfo, the Cochrane Library and Opengrey were searched from inception to May 2017. STUDY APPRAISAL AND SYNTHESIS METHODS: The Newcastle-Ottawa Scale was used to assess risk of bias. A narrative synthesis of results was performed due to differences between studies. RESULTS: Twenty studies were included. None of the studies controlled for all prespecified confounding factors (age, gender, socioeconomic status and severity of dementia). Reporting of results was inadequate with many studies simply reporting whether associations were 'statistically significant' without providing effect size estimates or CIs. There was a suggestion of an association between relationship factors and global challenging behaviour. All studies evaluating global challenging behaviour provided statistical evidence of an association (most P values below 0.02). There was no consistent evidence for an association for any other outcome assessed. CONCLUSIONS: There is currently no strong or consistent evidence on the effects of relationship factors on institutionalisation, hospitalisation, death or quality of life for people with dementia. There was a suggestion of an association between relationship factors and challenging behaviour, although the evidence for this was weak. To improve our ability to support those with dementia and their families, further robust studies are needed. PROSPERO REGISTRATION NUMBER: CRD42015020518.


Assuntos
Cuidadores/psicologia , Demência/psicologia , Relações Familiares , Qualidade de Vida , Adaptação Psicológica , Demência/mortalidade , Hospitalização/estatística & dados numéricos , Humanos , Fatores de Risco
17.
Trials ; 19(1): 23, 2018 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-29321046

RESUMO

BACKGROUND: Applications of causal inference methods to randomised controlled trial (RCT) data have usually focused on adjusting for compliance with the randomised intervention rather than on using RCT data to address other, non-randomised questions. In this paper we review use of causal inference methods to assess the impact of aspects of patient management other than the randomised intervention in RCTs. METHODS: We identified papers that used causal inference methodology in RCT data from Medline, Premedline, Embase, Cochrane Library, and Web of Science from 1986 to September 2014, using a forward citation search of five seminal papers, and a keyword search. We did not include studies where inverse probability weighting was used solely to balance baseline characteristics, adjust for loss to follow-up or adjust for non-compliance to randomised treatment. Studies where the exposure could not be assigned were also excluded. RESULTS: There were 25 papers identified. Nearly half the papers (11/25) estimated the causal effect of concomitant medication on outcome. The remainder were concerned with post-randomisation treatment regimens (sequential treatments, n =5 ), effects of treatment timing (n = 2) and treatment dosing or duration (n = 7). Examples were found in cardiovascular disease (n = 5), HIV (n = 7), cancer (n = 6), mental health (n = 4), paediatrics (n = 2) and transfusion medicine (n = 1). The most common method implemented was a marginal structural model with inverse probability of treatment weighting. CONCLUSIONS: Examples of studies which exploit RCT data to address non-randomised questions using causal inference methodology remain relatively limited, despite the growth in methodological development and increasing utilisation in observational studies. Further efforts may be needed to promote use of causal methods to address additional clinical questions within RCTs to maximise their value.


Assuntos
Análise de Dados , Ensaios Clínicos Controlados Aleatórios como Assunto , Humanos , Probabilidade
18.
Int J Equity Health ; 17(1): 8, 2018 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-29338739

RESUMO

BACKGROUND: Excessive drinking leads to poor absorption of nutrients and homeless problem-drinkers often have nutritionally inadequate diets. Depletion of nutrients such as vitamin B1 can lead to cognitive impairment, which can hinder efforts to reduce drinking or engage with services. This review aimed to assess effectiveness of interventions designed to prevent or treat malnutrition in homeless problem-drinkers. METHODS: We systematically searched nine electronic databases and 13 grey literature sources for studies evaluating interventions to improve nutrition in homeless populations, without regional or language restrictions. Screening for inclusion was done in duplicate. One reviewer extracted data and assessed risk of bias, and another checked the extractions. Primary outcomes were nutrition status/deficiency, liver damage, and cognitive function. Secondary outcomes included abstinence, comorbidities, resource use, acceptability and engagement with intervention. Results were synthesised narratively. RESULTS: We included 25 studies (2 Randomised Controlled Trials; 15 uncontrolled before and after; 7 surveys; 1 case-control). Nine studies evaluated educational and support interventions, five food provision, and three supplement provision. Eight studies evaluated a combination of these interventions. No two interventions were the same, and all studies were at high risk of bias. Nutritional status (intake/ deficiency) were reported in 11 studies and liver function in one. Fruit and vegetable intake improved with some education and support interventions (n = 4 studies) but not others (n = 2). Vitamin supplements appeared to improve vitamin deficiency levels in the blood (n = 2). Free or subsidised meals (n = 4) and food packs (n = 1) did not always fulfil dietary needs, but were usually considered acceptable by users. Some multicomponent interventions improved nutrition (n = 3) but acceptability varied (n = 3). No study reported cost effectiveness. CONCLUSIONS: The evidence for any one intervention for improving malnutrition in homeless problem-drinkers was based on single studies at high risk of bias. Various food and supplement provision interventions appear effective in changing nutritional status in single studies. Educational and multicomponent interventions show improved nutritional behaviour in some studies but not others. Further better quality evidence is required before these interventions can be recommended for implementation. Any future studies should seek the end user input in their design and conduct. TRIAL REGISTRATION: Registered with PROSPERO: CRD42015024247 .


Assuntos
Consumo de Bebidas Alcoólicas/terapia , Alcoolismo/terapia , Pessoas em Situação de Rua , Desnutrição/terapia , Estado Nutricional , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
J Clin Epidemiol ; 95: 45-54, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29217451

RESUMO

OBJECTIVE: We investigated the associations between risk of bias judgments from Cochrane reviews for sequence generation, allocation concealment and blinding, and between-trial heterogeneity. STUDY DESIGN AND SETTING: Bayesian hierarchical models were fitted to binary data from 117 meta-analyses, to estimate the ratio λ by which heterogeneity changes for trials at high/unclear risk of bias compared with trials at low risk of bias. We estimated the proportion of between-trial heterogeneity in each meta-analysis that could be explained by the bias associated with specific design characteristics. RESULTS: Univariable analyses showed that heterogeneity variances were, on average, increased among trials at high/unclear risk of bias for sequence generation (λˆ 1.14, 95% interval: 0.57-2.30) and blinding (λˆ 1.74, 95% interval: 0.85-3.47). Trials at high/unclear risk of bias for allocation concealment were on average less heterogeneous (λˆ 0.75, 95% interval: 0.35-1.61). Multivariable analyses showed that a median of 37% (95% interval: 0-71%) heterogeneity variance could be explained by trials at high/unclear risk of bias for sequence generation, allocation concealment, and/or blinding. All 95% intervals for changes in heterogeneity were wide and included the null of no difference. CONCLUSION: Our interpretation of the results is limited by imprecise estimates. There is some indication that between-trial heterogeneity could be partially explained by reported design characteristics, and hence adjustment for bias could potentially improve accuracy of meta-analysis results.


Assuntos
Metanálise como Assunto , Projetos de Pesquisa/normas , Teorema de Bayes , Viés , Interpretação Estatística de Dados , Projetos de Pesquisa Epidemiológica , Humanos
20.
Am J Epidemiol ; 187(5): 1113-1122, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29126260

RESUMO

Flaws in the design of randomized trials may bias intervention effect estimates and increase between-trial heterogeneity. Empirical evidence suggests that these problems are greatest for subjectively assessed outcomes. For the Risk of Bias in Evidence Synthesis (ROBES) Study, we extracted risk-of-bias judgements (for sequence generation, allocation concealment, blinding, and incomplete data) from a large collection of meta-analyses published in the Cochrane Library (issue 4; April 2011). We categorized outcome measures as mortality, other objective outcome, or subjective outcome, and we estimated associations of bias judgements with intervention effect estimates using Bayesian hierarchical models. Among 2,443 randomized trials in 228 meta-analyses, intervention effect estimates were, on average, exaggerated in trials with high or unclear (versus low) risk-of-bias judgements for sequence generation (ratio of odds ratios (ROR) = 0.91, 95% credible interval (CrI): 0.86, 0.98), allocation concealment (ROR = 0.92, 95% CrI: 0.86, 0.98), and blinding (ROR = 0.87, 95% CrI: 0.80, 0.93). In contrast to previous work, we did not observe consistently different bias for subjective outcomes compared with mortality. However, we found an increase in between-trial heterogeneity associated with lack of blinding in meta-analyses with subjective outcomes. Inconsistency in criteria for risk-of-bias judgements applied by individual reviewers is a likely limitation of routinely collected bias assessments. Inadequate randomization and lack of blinding may lead to exaggeration of intervention effect estimates in randomized trials.


Assuntos
Viés , Avaliação de Resultados em Cuidados de Saúde/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Teorema de Bayes , Estudos Epidemiológicos , Humanos , Metanálise como Assunto , Razão de Chances
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