Chair (Stream 1): Andrew Holmes (New Zealand Ministry of Health)
Chair:(Stream 2) Pat Crowley (Cochrane Pregnancy & Chilbirth Review Group)
The use of systematic reviews by Australian neonatologists and obstetricians
Authors: Christopher Jordens, Penelope Hawe, Les Irwig, (Department of Public Health and Community Medicine, University of Sydney), David Henderson-Smart, Deborah Donoghue (Australian and New Zealand Neonatal Network), Margaret Ryan, Roger Gabb, Ian Fraser (Royal Australian College of Obstetricians and Gynaecologists)
Background: Systematic reviews in obstetrics and neonatology have been available to practitioners for some years now through the Cochrane Pregnancy and Childbirth Database, the Oxford Database of Perinatal Trials, Effective Care in Pregnancy and Childbirth and Effective Care of the Newborn Infant.
Objectives: To determine current awareness of, access to and use of these resources among Australian neonatologists and obstetricians.
Methods: We contacted all 104 neonatologists and a random sample of 145 obstetricians. Using a structured telephone interview, we questioned respondents about information sources they use to keep up with their field and solve clinical problems. We then questioned them directly about the resources listed above. Clinicians who used these resources were asked how often and why they used them, and whether using them had changed their clinical practice.
Results: 90% of eligible clinicians completed the interview. 21% of neonatologists and 17% of obstetricians mentioned systematic reviews without prompting from the interviewer. When questioned about specific resources, 72% (95% CI 64% to 81%) of neonatologists and 44% (95% CI 36% to 53%) of obstetricians report using systematic reviews in one form or another. Neonatologists consulted a textbook more frequently than a database by a ratio of 2:1. Patient care was the most frequently cited reason for consulting systematic reviews. Of those neonatologists who used systematic reviews, half could cite an example of a treatment policy they had altered in response to a systematic review. Three factors independently predicted the use of systematic reviews among neonatologists: attendance at Australian Perinatal Society meetings; authorship of research, and familiarity with computers.
Conclusions: There is evidence that Australian neonatologists and obstetricians are using systematic reviews and modifying their practice accordingly. To maximise the benefit to patient care, however, there needs to be wider dissemination and implementation of evidence from databases of systematic reviews.
Systematic review of the effectiveness of specific anti-hypertensive drug therapy
Authors: Wright J.M, Lee C.H, Adams S.P, Chambers G.K.
Background: Hypertension is a common condition associated with an increased risk of cardiovascular disease and mortality. Anti-hypertensive treatment is important because of evidence that it is effective in reducing this increased morbidity and mortality. Data on the effectiveness of different classes and doses of drugs would be helpful to physicians to make selection of anti-hypertensive therapy more evidence-based.
Objectives: To assess the comparative effectiveness of antihypertensive therapy based on (1) low-dose thiazides, high-dose thiazides and beta-blockers vs. placebo and (2) thiazides vs. beta-blockers, in pre-venting cardiovascular morbidity and mortality.
Methods: All published randomized controlled trials (RCT) examining either the effectiveness of individual drugs vs. placebo or the relative effectiveness of thiazide and beta-blocker were identified through MEDLINE search and reference lists of articles. The identified trials were reviewed independently by 3 reviewers against a pre-established set of criteria. Only the results from the trials meeting the criteria were included in the meta-analysis and all the comparisons were made in terms of four outcomes: total cardiovascular events, total mortality, total stroke events and total CHD events.
Results: In the placebo RCT of individual treatment low-dose thiazide based treatment was found to statistically lower total mortality ( odds ratio, 0.80; 99% CI. 0.68 to 0.95; p<0.01), and the risk of total CHD ( odds ratio 0.70; CI, 0.57 to 0.86) while high-dose thiazide based treatment did not. Beta-blocker based treatments did not show statistically significant risk reduction in any of the endpoint categories. In the comparison between thiazide and beta-blocker based treatments, there is a trend for thiazides to be better for all outcomes, but none was statistically significant.
Conclusions: In placebo controlled trials, low-dose thiazides appear to reduce adverse cardiac outcomes better than high-dose thiazides or beta-blockers. In thiazide vs. beta-blocker RCT's, there a trend towards a better outcome with thiazide.
Results from RCTs and systematic reviews: to whom do they apply?
Authors: Dianne O'Connell, David Henry, Paul Glasziou, Jasminka Sarunac, Suzanne Hill, Julia Lowe, David Sackett.
Background: Evidence-based medicine involves the application of findings from randomised controlled trials (RCTs) and systematic reviews to clinical practice. However the identification of individual patients in whom the benefits of a particular treatment will outweigh the risks is problematic.
Objectives: (1) To undertake a systematic review of the literature on the applicability (or generalisability) of results from RCTs or systematic reviews. (2) To produce a pragmatic guide on how to assess applicability and how to use the findings of RCTs to identify subgroups in the community who are likely to benefit from a particular treatment.
Methods: A literature search is in progress using Medline, hand searching of key journals and checking references from identified papers. The papers are being reviewed by study members, grouped into subject areas and annotated bibliographies will be produced. From these, a synthesis of the literature will be compiled describing the methods currently used to assess applicability, the assumptions required and areas for further research.
Results: So far we have identified 378 articles to be reviewed. Initial impressions suggest that there are very few papers addressing general methods for assessing applicability. The majority tend to focus on a particular aspect such as subgroup analysis, patient selection or heterogeneity of treatment effect. A summary of the literature and preliminary conclusions will be presented at the meeting.
Implications: This project should contribute to better policy and clinical decisions regarding the implementation and funding of new technologies based on an accurate appraisal of the applicability of the findings from RCTs and systematic reviews to particular groups of patients in hospital, general practice and community settings.
Consumer health information providers and Cochrane reviews
Authors: Vikki Entwistle, Ian Watt, James Herring NHS Centre for Reviews and Dissemination, University of York, UK; Queen Margaret College, Edinburgh, UK
Abstract: Consumer health information services respond to a wide range of health related enquiries from patients and members of the public. Traditionally, they have provided readily understandable information about the nature of health problems, health care processes, local services and self help groups. They are now increasingly expected, by both their funders and their enquirers, to provide information about the effectiveness of health care interventions, which can be used to inform consumer participation in treatment decisions.
Many consumer health information services do not yet have the skills or resources needed to provide good quality research based information about health care effectiveness in formats which are appropriate for their enquirers.
This paper considers issues surrounding the use of the Cochrane Database of Systematic Reviews and other research based information sources by consumer health information providers. It draws on issues raised during a workshop of consumer health information providers in Scotland, and discusses in particular:
Quality of randomised controlled trials included in meta-analyses: how often and how is it assessed?
Authors: Jadad AR, Cook DJ, Jones AL, Klassen T, Moher M, Tugwell P, Moher D
Background: The assessment of the quality of reporting of randomised controlled trials included in meta-analysis remains controversial. Some researchers see quality assessment as a source of bias or as completely uninformative, while others regard it as an important strategy to identify and reduce bias. The amount of empirical evidence to inform these extreme positions, however, is insufficient. This study is part of a larger project that attempts to generate the empirical evidence necessary to resolve the controversy.
Objective: To estimate the proportion of published meta-analysis in which the quality of randomised controlled trials has been assessed, and the methods used to obtain and incorporate the assessments into the results of the meta-analyses.
Methods: We selected two populations of meta-analyses of randomised controlled trials: 36 from the Cochrane Database of Systematic Reviews, and 204 selected randomly from Medline. Each meta-analysis is being evaluated using 28 different questions related to quality assessment. The reviewers are completing the evaluations in pairs, masked to all journal identifiers. Before completing these assessments an inter-observer reliability study was completed using 10 separate meta-analyses.
Results: We will present descriptive and comparative results on the individual items assessed. We will also present time trends of quality assessment.
A Systematic Overview of School-Based Adolescent Suicide Prevention Programs
Authors: Jenny Ploeg, Donna Ciliska, Maureen Dobbins, Sarah Hayward, Helen Thomas, Jane Underwood. Regional Municipality of Hamilton-Wentworth Department of Public Health Services, Hamilton, Ontario, Canada.
Background: The best available evidence for many community health interventions, such as adolescent suicide prevention programs, is seldom based on randomized trials. Alternative overview methods are required to summarize the literature and make recommendations for practice.
Objectives: To develop a method to systematically appraise and summarize evidence on the effectiveness of adolescent suicide prevention programs and to summarize strategies used to disseminate results to practice settings.
Methods: Search strategies included on-line searches, hand searches of selected journals, and searches of reference lists. In total, 187 articles published between 1980 and 1995 were retrieved. Articles were assessed for relevance and validity by two independent reviewers. Articles were relevant if they evaluated a program within the scope of Public Health Nursing practice and gave information on student outcomes. The five validity criteria included method of allocation to study group, level of agreement to participate, control for confounders, method of data collection, and percent of subjects available for follow up. Articles were given an overall rating of strong, moderate or weak.
Results: Only eleven articles met the relevance criteria. All of these articles were rated weak, meaning that at least one criterion was rated fail. The most common weaknesses of the articles included lack of description of randomization, inadequate control for potential confounders and lack of pretesting of instruments. The evidence suggests that there may be both beneficial and harmful effects of the programs on some students, and that the potential negative effects, especially among males, could have serious consequences. Results have been disseminated in short reports, presentations and through the Internet.
Conclusions: The methods of this systematic overview have facilitated optimal use of the available evidence related to adolescent suicide prevention programs and can be used to appraise and summarize the effectiveness of other community health interventions.
Assessing the efficacy of anti-depressant treatment: methodological considerations for meta-analysis
Authors: Philippe Cialdella, Margaret Haugh, Jean-Pierre Boissel (The French Cochrane Centre, France); Per Bech (Frederiksborg General Hospital, Denmark), Martin Birkett, (Eli Lilly, UK)
Background: The "gold-standard" for analysing clinical trial data individually and in reviews is the intention-to-treat approach whereby patients are analysed in the group to which they were allocated, irrespective of the treatment they actually received. It can be argued that although this reduces the risk of certain biases, it does not represent the real situation in which patients do not follow a treatment for the time initially prescribed. We will use the example of fluoxetine treatment for major depression to illustrate this problem.
Objective: To examine the effect of the different analytical approaches for data from a clinical trial on the results of a meta-analysis.
Methods: Using the Eli Lilly Fluoxetine database, we selected trials in which fluoxetine was compared with tricyclic antidepressants (TCA) performed in the United States (US) and those performed outside the US (non-US) that satisfied our predefined inclusion criteria. The primary outcome was defined as a binary variable; partial remission, i.e. at least 50% reduction compared with the baseline score on the HDRS-17 instrument. Three types of analyses were performed using "a last observation carried forward" technique; 1) intention-to-treat; 2) patients that had completed at least 4 weeks therapy (efficacy analysis), and 3) patients that had at least one post-baseline visit (endpoint analysis). The logarithm of the odds ratio method was used.
Results:
Type of analysis OR [95% CI] p-assoc p-homo US vs TCA (11 trials; n = 1370) Intention to treat 1.18 [0.94; 1.48] 0.149 0.886 Efficacy 0.93 [0.71; 1.22] 0.599 0.593 Endpoint 1.10 [0.88; 1.37] 0.402 0.377 Non-US vs TCA (13 trials; n = 643) Intention to treat 0.80 [0.58; 1.12] 0.196 0.576 Efficacy 0.62 [0.42; 0.92] 0.019 0.608 Endpoint 0.73 [0.53; 1.02] 0.063 0.303
Conclusions: The efficacy and endpoint analyses gave similar results, whereas the efficacy analysis resulted in a lower value for the point estimate of the treatment effect.
Classification Criteria for Chronic Fatigue Syndrome
Authors: Axel Hoffmann, Roland Linder, Bernd Kroeger, Hans-Gerd Lipinski, Gerhard R.F. Krueger
Background: The following classification criteria (CC) for chronic fatigue syndrome (CFS) were based upon a prospective randomized multi-centre longitudinal study of 198 patients with severe fatigue over 6 months. For the first time the statistical value was determined of 26 CFS symptoms by comparing them with a control group consisting of patients with fibromyalgia (FMA) and systemic lupus erythematosus (SLE). These diseases are also associated with severe fatigue and they are well defined.
Objectives: To determine the statistical value of CFS symptoms and to develop classification criteria.
Methods: The CC were determined according to the recommendations of the American College of Rheumatology (ACR) using a collective of 158 randomized patients (CFS: n=79, male:female (m:f) 38:41, mean age 41.8 years; FMA: n=54, m:f 8:46, mean age 50.7 years; SLE: n=25, m:f 3:22, mean age 49.6 years). These include CC in the traditional format (TFC), regression coefficients criteria (RCC) and regression tree criteria (RTC). A validation of CC-CFS was undertaken with a collective of a further 40 patients (CFS: n=20, m:f 9:11, mean age 41.7 years; FMA: n=4, m:f 1:3, mean age 52.0 years; SLE: n=16, m:f 4:12, mean age 48.1 years), which had not been used for the generation of the criteria. A comparison to the CDC criteria was undertaken.
Results: The CC were shown to be easy to apply and to have high accuracies (A) and high validities (V) as TFC: A 94.3%, V 77.5%, RCC: A 97.5%, V 82.5% and RTC: A 98.7%, V 82.5%. The CDC criteria from Holmes yielded A 78.3% and V 62.5%. Sudden onset of fatigue and sore throat were demonstrated to be the most discriminative symptoms in CFS.
Conclusions: Using only clinical data the CC allow a reliable and valid classification with a well characterized symptomatology, which suggests an infectious aetiology in CFS.
This page was last updated on 15 November 1996
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