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David Moher

Publications and source records attributed to David Moher.

At least 37 records · Page 2Linked to original sources
PubMed2006

Critical appraisal of clinical studies in Chinese herbal medicine.

The use of complementary and alternative medicine (CAM) is currently widespread and appears to be growing. As an increasing proportion of the population turns to CAM therapies, whether singly or in combination with allopathic medicine, the need for quality research in this area is reinforced. Much of this research consists of clinical studies aimed primarily at clinicians, yet challenges arising from poor methodological quality will occur when interpreting study findings and their implications. For clinicians to be effective consumers of the scientific literature, familiarization with the principles of evidence-based medicine (EBM) is essential. The goal of this review is to introduce clinicians to the concept of critical appraisal of clinical studies and foster critical thinking when reading research articles in order to best evaluate and incorporate study findings into their daily practice. Topics discussed in this article include: (1) fundamentals of EBM; (2) types of clinical studies; (3) hierarchy of evidence; (4) Consolidated Standard of Randomized Trials (CONSORT) statement to evaluate the quality of reporting in randomized controlled trials (RCTs); (5) methodologic quality rating scales for RCTs; and (6) issues specific to evaluating studies of Chinese herbal medicine.

Evidence-Based Medicine↗
PubMed2005

[Developing guidelines for reporting healthcare research: scientific rationale and procedures].

Healthcare research is extremely important, with the clear potential to influence treatment and prevention of disease, possibly on a global scale. Yet deficiencies in how research studies are reported are both well-documented and widespread across all medical specialties, types of interventions and study designs. Although randomised trials have received the most attention in this regard, similar concerns have been expressed about reporting of other types of research including diagnostic and epidemiological studies. If a journal article describes in enough detail what was done at each stage of a study, readers will have enough information to allow them to decide on the merits of the results for themselves. From this simple idea comes the scientific rationale of developing guidelines on how to report research. We consider desirable attributes of such guidelines, emphasising the importance of being evidence-based where possible. We describe recommended processes to produce guidelines that have evolved over several years during the preparation of a sequence of reporting guidelines including CONSORT, QUOROM, STARD and STROBE.

Authorship↗
PubMed2005

A checklist to evaluate a report of a nonpharmacological trial (CLEAR NPT) was developed using consensus.

BACKGROUND AND OBJECTIVE: To develop a checklist of items measuring the quality of reports of randomized clinical trials (RCTs) assessing nonpharmacological treatments (NPTs). STUDY DESIGN AND SETTING: The Delphi consensus method was used to select and reduce the number of items in the checklist. A total of 154 individuals were invited to participate: epidemiologists and statisticians involved in the field of methodology of RCTs (n = 55), members of the Cochrane Collaboration (n = 41), and clinicians involved in planning NPT clinical trials (n = 58). Participants ranked on a 10-point Likert scale whether an item should be included in the checklist. RESULTS: Fifty-five experts (36%) participated in the survey. They were experienced in systematic reviews (68% were involved in the Cochrane Collaboration) and in planning RCTs (76%). Three rounds of the Delphi method were conducted to achieve consensus. The final checklist contains 10 items and 5 subitems, with items related to the standardization of the intervention, care provider influence, and additional measures to minimize the potential bias from lack of blinding of participants, care providers, and outcome assessors. CONCLUSIONS: This tool can be used to critically appraise the medical literature, design NPT studies, and assess the quality of trial reports included in systematic reviews.

Consensus↗
PubMed2005

A randomized, double-blind, placebo-controlled noninferiority trial of amoxicillin for clinically diagnosed acute otitis media in children 6 months to 5 years of age.

OBJECTIVES: Debate continues with respect to a "watch and wait" approach versus immediate antibiotic treatment for the initial treatment of acute otitis media. In this double-blind noninferiority trial, we compared clinical improvement rates at 14 days for children (6 months to 5 years of age) with acute otitis media who were randomly assigned to receive amoxicillin or placebo. METHODS: We enrolled healthy children who presented to clinics or the emergency department with a new episode of acute otitis media during the fall and winter months in Ottawa (from December 1999 to the end of March 2002). The children were randomly assigned to receive amoxicillin (60 mg/kg daily) or placebo for 10 days. Telephone follow-up was performed on each of days 1, 2 and 3 and once between day 10 and day 14. The primary outcome was clinical resolution of symptoms, defined as absence of receipt of an antimicrobial (other than the amoxicillin in the treatment group) at any time during the 14-day period. Secondary outcomes were the presence of pain and fever and the activity level in the first 3 days, recurrence rates, and the presence of middle ear effusion at 1 and 3 months. RESULTS: According to clinical scoring, 415 of the 512 children who could be evaluated had moderate disease. At 14 days 84.2% of the children receiving placebo and 92.8% of those receiving amoxicillin had clinical resolution of symptoms (absolute difference -8.6%, 95% confidence interval -14.4% to -3.0%). Children who received placebo had more pain and fever in the first 2 days. There were no statistical differences in adverse events between the 2 groups, nor were there any significant differences in recurrence rates or middle ear effusion at 1 and 3 months. INTERPRETATION: Our results did not support the hypothesis that placebo was noninferior to amoxicillin (i.e., that the 14-day cure rates among children with clinically diagnosed acute otitis media would not be substantially worse in the placebo group than the treatment group). Nevertheless, delaying treatment was associated with resolution of clinical signs and symptoms in most of the children.

Acute Disease↗
PubMed2005

The CONSORT Statement: revised recommendations for improving the quality of reports of parallel-group randomized trials 2001.

To comprehend the result of a randomized controlled trial (RCT), readers must understand its design, conduct, analysis and interpretation. That goal can be achieved only through complete transparency from authors. Despite several decades of educational efforts, the reporting of RCTs needs improvement. Investigators and editors developed the original CONSORT (Consolidated Standards of Reporting Trials) statement to help authors improve reporting by using a checklist and flow diagram. The revised CONSORT statement presented in this article incorporates new evidence and addresses some criticism of the original statement. The checklist items pertain to the content of the Title, Abstract, Introduction, Methods, Results, and Comment. The revised checklist includes 22 items selected because empirical evidence indicates that not reporting the information is associated with biased estimates of treatment effect or because the information is essential to judge the reliability or relevance of the findings. We intended the flow diagram to depict the passage or participants through an RCT. The revised flow diagram depicts information from 4 stages of a trial (enrollment, intervention allocation, follow-up and analysis). The diagram explicitly includes the number of participants, according to each intervention group, included in the primary data analysis. Inclusion of these numbers allows the reader to judge whether the authors have performed an intention-to-treat analysis. In sum, the CONSORT statement is intended to improve the reporting or an RCT, enabling readers to understand a trial's conduct and to assess the validity of its results.

Guidelines as Topic↗
PubMed2005

For randomized controlled trials, the quality of reports of complementary and alternative medicine was as good as reports of conventional medicine.

OBJECTIVE: To compare the quality of reporting of reports randomized controlled trials (RCTs) published in English and in languages other than English (LOE), and to determine whether there were differences between conventional medicine (CM) and complementary and alternative medicine (CAM) reports. STUDY DESIGN AND SETTING: We examined more than 600 RCTs associated with 125 systematic reviews. We extracted characteristics of each RCT using a standardized data collection form. We assessed quality using the Jadad scale and the adequacy of allocation concealment. RESULTS: There were only minor differences in the quality of reports of RCTs published in English compared with other languages (median quality score of 3 vs. 2, P=.10), and the quality of reports of CAM RCTs was similar to the CM reports (median score of 3 vs. 2, P=.14). There was no effect of language of publication on quality of reporting for CM trials (median score of 2 vs. 2, P=.12). Among CAM trials, however, overall quality scores were higher for reports in English than for reports in other languages (median score of 3 vs. 2, P=.04). CONCLUSION: The overall quality of reports published in languages other than English is similar to that of English-language reports. Moreover, the overall quality of reporting of RCTs of CAM interventions is as good as that for CM interventions.

Bibliometrics↗
PubMed2005

Language of publication restrictions in systematic reviews gave different results depending on whether the intervention was conventional or complementary.

OBJECTIVE: To assess whether language of publication restrictions impact the estimates of an intervention's effectiveness, whether such impact is similar for conventional medicine and complementary medicine interventions, and whether the results are influenced by publication bias and statistical heterogeneity. STUDY DESIGN AND SETTING: We set out to examine the extent to which including reports of randomized controlled trials (RCTs) in languages other than English (LOE) influences the results of systematic reviews, using a broad dataset of 42 language-inclusive systematic reviews, involving 662 RCTs, including both conventional medicine (CM) and complementary and alternative medicine (CAM) interventions. RESULTS: For CM interventions, language-restricted systematic reviews, compared with language-inclusive ones, did not introduce biased results, in terms of estimates of intervention effectiveness (random effects ration of odds rations ROR=1.02; 95% CI=0.83-1.26). For CAM interventions, however, language-restricted systematic reviews resulted in a 63% smaller protective effect estimate than language-inclusive reviews (random effects ROR=1.63; 95% CI=1.03-2.60). CONCLUSION: Language restrictions do not change the results of CM systematic reviews but do substantially alter the results of CAM systematic reviews. These findings are robust even after sensitivity analyses, and do not appear to be influenced by statistical heterogeneity and publication bias.

Complementary Therapies↗
PubMed2005

Systematic reviews involving complementary and alternative medicine interventions had higher quality of reporting than conventional medicine reviews.

OBJECTIVE: To compare the quality of systematic reviews reported in English and in languages other than English, and to determine whether there are differences between conventional medicine (CM) and complementary and alternative medicine (CAM) reports. STUDY DESIGN AND SETTING: We used the Oxman and Guyatt (OG) scale to assess the quality of reporting in 130 systematic reviews: 50 were language-restricted, 32 were language-inclusive but only English-language (EL) trials contained (inclusive-EL), and 48 were language-inclusive and included trials published in languages other than English (inclusive-LOE). Of the 130 reviews, 105 addressed CM interventions and 25 addressed CAM interventions. RESULTS: Comparison of the systematic reviews showed that the quality of reporting and reporting characteristics are not affected by inclusion or exclusion of LOE; however, the quality of reporting of systematic reviews involving CAM interventions is higher than that of reviews focusing on CM interventions. CONCLUSION: Informal comparison of the OG scale with the data collected on quality assessments showed that the OG scale performs well overall but may not identify important differences in comprehensiveness of the search strategy and avoidance of bias in study selection. Further research is required to determine the best methods for assessing quality of systematic reviews and whether the effect of language restrictions is dependent on the type of intervention (CM or CAM).

Bias↗
PubMed2005

The prevalence of celiac disease in average-risk and at-risk Western European populations: a systematic review.

Until recently, celiac disease (CD) was felt to be a rare disease in the United States. The aim of this study was to conduct a systematic review of the prevalence of CD in general Western populations and in populations at high risk for CD. Standard systematic review methodology was used. A literature search was conducted in MEDLINE (1966 to October 2003) and EMBASE (1974 to December 2003) databases. Qualitative and quantitative prevalence estimates were produced after assessing study heterogeneity. The prevalence of CD in general Western populations is close to 1% and is somewhat higher in certain Western European populations. The prevalence of CD in populations at risk for CD is as follows: 3%-6% in type 1 diabetic patients, up to 20% in first-degree relatives, 10%-15% in symptomatic iron-deficiency anemia (IDA), 3%-6% in asymptomatic IDA, and 1%-3% in osteoporosis. The prevalence of CD in patients suspected of having CD varied depending on the reasons for suspecting CD and on whether the study was conducted in a referral center. In general, the prevalence ranged from 5% to 15%, but was up to 50% in symptomatic patients evaluated in a tertiary referral center. CD is a common medical condition. The prevalence is higher still in high-risk groups. Clinicians in a variety of specialties should have a high index of suspicion for the diagnosis of CD and in particular need to pay close attention to the identified high-risk groups.

Adult↗
PubMed2005

Consequences of testing for celiac disease.

Population screening studies have identified that up to two thirds of celiac disease (CD) cases are asymptomatic. The aim of this study was to conduct a systematic review of the expected consequences of testing for CD in the following populations: (1) patients with symptoms suggestive of CD, (2) asymptomatic at-risk populations, and (3) general population. Standard systematic review methodology was used. A comprehensive literature search was conducted in MEDLINE (1996-2003), EMBASE (1974-2003), CAB (1972 forward), PsychINFO (1840-2003), AGRICOLA (1970-2003), and Sociological Abstracts (1963 forward); searches were conducted in December 2003. Pooled summary estimates were not calculated. The majority of the included studies were before-after studies, case control, or retrospective cohorts. The quality of evidence for the before-after studies is weaker. The overall strength of the evidence for this issue was fair to good. This area of research is relatively new, and further high-quality studies are required. The consequences of testing for celiac disease in symptomatic individuals appears to have a positive impact on patient-relevant outcomes. The data are less clear for those with silent CD or those with lower grade histologic lesions in small bowel biopsy. The literature suggests that compliance is less than ideal in these individuals, especially if diagnosed when adults. Long-term outcomes have not been extensively studied in those with silent CD.

Adult↗
PubMed2005

The diagnostic accuracy of serologic tests for celiac disease: a systematic review.

Clinicians are increasingly utilizing noninvasive serologic tests for the diagnosis and screening of celiac disease (CD). The aim of this study was to conduct a systematic review of the diagnostic performance of serologic tests for the diagnosis and screening of CD. Standard systematic review methodology was used. A literature search was conducted in MEDLINE (1966 to October 2003) and EMBASE (1974 to December 2003) databases. A weighted mean of the sensitivity and specificity along with 95% confidence intervals and summary receiver operating characteristic (ROC) curves were calculated. The pooled specificity of endomyseal antibody (EMA)-monkey esophagus (ME) or EMA-human umbilical cord (HU) was close to 100% in adults and children. The pooled specificity of transglutaminase antibody (tTG)-guinea pig (GP) and tTG-human recombinant (HR) were between 95% and 99%. IgA-EMA-ME demonstrated sensitivities of 96% and 97% in children and adults, respectively. EMA-HU demonstrated a similar sensitivity of 97% in children but 90% in adults. The pooled sensitivity of tTG-GP in adults and children was 90% and 93%, respectively. The sensitivity of tTG-HR was 98% and 96%, respectively. The performance of antigliadin antibody was inferior to that of EMA and tTG. EMA and tTG offer high sensitivity and specificity. The sensitivity of these tests appears to be lower than reported when milder histologic grades are used to define CD (below 90%). If true, the nearly perfect negative predictive value of these tests would drop. The positive predictive value of these tests is likely lower than reported when the tests are applied in low-prevalence populations.

Antibodies↗
PubMed2005

The influence of display and statistical factors on the interpretation of metaanalysis results by physicians.

OBJECTIVE: The objective of this study was to determine the extent to which various factors affect the interpretation of metaanalytic results by physicians. STUDY DESIGN: A sample of 120 physicians, selected from The Royal College of Physicians and Surgeons of Canada (RCPSC), was randomly assigned to 1 of 6 groups (n = 20) created from a combination of 3 summary measures and 2 levels of disease severity. The intervention consisted of a written scenario and 4 individual displays of metaanalyses (M-A), each followed by questions related to the interpretation of results of M-A. Two final questions examined statistical familiarity/proficiency with the summary measures used. DATA ANALYSIS: Analyses of variance examined main effects and interactions among 4 factors: summary measure, disease severity, effect size, and statistical consistency of the studies comprising the metaanalysis. Two outcomes were examined: interpretation of the treatment effect and confidence in the interpretation of the treatment effect. PRINCIPAL FINDINGS: Physicians were more likely to favor treatment when the results of the primary randomized, controlled trials (RCTs) were statistically homogeneous (P = 0.001) and when the overall effect size was large (P = 0.001). Also, physicians were more likely to be confident when the results were homogeneous (P = 0.001) and when effect size was large (P = 0.000). Interactions also revealed that the effect of statistical consistency of contributing to RCTs was greatest when data were presented as risk difference for treatment outcome (P = 0.026) and when effect size was small (P = 0.000). CONCLUSIONS: The interpretation of metaanalytic displays is influenced by the overall effect size of M-A, the statistical consistency of the contributing RCTs, and interactions of these factors with display factors.

Adult↗
PubMed2004

Better reporting of harms in randomized trials: an extension of the CONSORT statement.

In response to overwhelming evidence and the consequences of poor-quality reporting of randomized, controlled trials (RCTs), many medical journals and editorial groups have now endorsed the CONSORT (Consolidated Standards of Reporting Trials) statement, a 22-item checklist and flow diagram. Because CONSORT primarily aimed at improving the quality of reporting of efficacy, only 1 checklist item specifically addressed the reporting of safety. Considerable evidence suggests that reporting of harms-related data from RCTs also needs improvement. Members of the CONSORT Group, including journal editors and scientists, met in Montebello, Quebec, Canada, in May 2003 to address this problem. The result is the following document: the standard CONSORT checklist with 10 new recommendations about reporting harms-related issues, accompanying explanation, and examples to highlight specific aspects of proper reporting. We hope that this document, in conjunction with other CONSORT-related materials (http://www.consort-statement.org), will help authors improve their reporting of harms-related data from RCTs. Better reporting will help readers critically appraise and interpret trial results. Journals can support this goal by revising Instructions to Authors so that they refer authors to this document.

Evidence-Based Medicine↗
PubMed2004

Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative.

OBJECTIVE: Our aim was to improve the accuracy and completeness of reporting of studies of diagnostic accuracy in order to allow readers to assess the potential for bias in a study and to evaluate the generalizability of its results. METHODS: The Standards for Reporting of Diagnostic Accuracy (STARD) steering committee searched the literature to identify publications on the appropriate conduct and reporting of diagnostic studies and extracted potential items into an extensive list. Researchers, editors and members of professional organizations shortened this list during a 2-day consensus meeting with the goal of developing a checklist and a generic flow diagram for studies of diagnostic accuracy. RESULTS: The search for published guidelines about diagnostic research yielded 33 previously published checklists, from which we extracted a list of 75 potential items. At the consensus meeting, participants shortened the list to a 25-item checklist, by using evidence whenever available. A prototype of a flow diagram provides information about the method of recruitment of patients, the order of test execution and the numbers of patients undergoing the test under evaluation and/or the reference standard. CONCLUSIONS: Evaluation of research depends on complete and accurate reporting. If medical journals adopt the checklist and the flow diagram, the quality of reporting of studies of diagnostic accuracy should improve, to the advantage of clinicians, researchers, reviewers, journals and the public.

Bias↗