Meta-analysis of clinical trials as a scientific discipline. I: Control of bias and comparison with large co-operative trials

Evaluation of a health education program for improving uptake of HIV self-testing by men in Rwanda: a pilot pragmatic randomized control trial

Background

Health education interventions tailored to suit men have the potential to improve health outcomes for this underserved population. HIV self-testing (HIVST) is a promising approach to overcoming challenges associated with low HIV testing rates among men. The primary objective of this study is to assess the feasibility of conducting a definitive trial to determine the effectiveness of a locally adapted and optimized health education program (HEP) on the uptake of HIVST among men in Kigali, Rwanda.

Methods

This study employs a pilot pragmatic randomized controlled trial to evaluate an HIVST HEP for men. Participants were randomized to the intervention (HEP) arm or to the control arm. In the intervention group, the adapted HEP was administered in addition to routine health education. In the non-intervention group, only routine health education was offered. Participant data was collected first upon recruitment and then after 3 months’ follow-up using interviewer-administered questionnaires.

Results

There was a 100% response rate at enrollment and no loss to follow-up at exit. There was significant association between the study arm and knowledge of HIVST. Participants in the control arm had a mean knowledge score of 67% compared to 92% among participants in the intervention arm. There was an association between the study arm and HIVST uptake: 67% of the study participants in the intervention arm self-reported HIVST uptake compared to 23% of the participants in the control arm.

Discussion

This pilot study demonstrates the feasibility of a larger trial to assess the effectiveness of an HEP intervention on uptake of HIVST among men. We found preliminary evidence of increased uptake of HIVST in the intervention group.

Trial registration

Pan African Clinical Trial Registry PACTR201908758321490. Registered on 8 August 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00940-x.

Randomized Controlled Trials 6: Determining the Sample Size and Power for Clinical Trials and Cohort Studies

Performing well-powered, randomized, controlled trials is of fundamental importance in clinical research. The goal of sample size calculations is to assure that statistical power is sufficiently high when the probability of falsely rejecting a true null hypothesis (type I error) is kept acceptably small. This chapter overviews the fundamental of sample size calculation for standard types of outcomes for 2-group studies. It also considers (1) the problem of determining the size of the treatment effect that a study should be designed to detect, (2) modifications to sample size calculations to account for loss to follow-up and nonadherence, (3) options that can be used when initial calculations indicate that the feasible sample size is insufficient to provide adequate power, (4) implications of using multiple primary end points. In addition, a discussion of cluster randomized trials is provided. Sample size estimates for longitudinal cohort studies must take account of confounding by baseline factors.

Cigarette smoking and schizophrenia: Mendelian randomisation study

BACKGROUND

The link between schizophrenia and cigarette smoking has been well established through observational studies. However, the cause-effect relationship remains unclear.

AIMS

We conducted Mendelian randomisation analyses to assess any causal relationship between genetic variants related to four smoking-related traits and the risk of schizophrenia.

METHOD

We performed a two-sample Mendelian randomisation using summary statistics from genome-wide association studies (GWAS) of smoking-related traits and schizophrenia (7711 cases, 18 327 controls) in East Asian populations. Single nucleotide polymorphisms (SNPs) correlated with smoking behaviours (smoking initiation, smoking cessation, age at smoking initiation and quantity of smoking) were investigated in relation to schizophrenia using the inverse-variance weighted (IVW) method. Further sensitivity analyses, including Mendelian randomisation-Egger (MR-Egger), weighted median estimates and leave-one-out analysis, were used to test the consistency of the results.

RESULTS

The associated SNPs for the four smoking behaviours were not significantly associated with schizophrenia status. Pleiotropy did not inappropriately affect the results.

CONCLUSIONS

Cigarette smoking is a complex behaviour in people with schizophrenia. Understanding factors underlying the observed association remains important; however, our findings do not support a causal role of smoking in influencing risk of schizophrenia.

Body Mass Index and Polycystic Ovary Syndrome: A 2-Sample Bidirectional Mendelian Randomization Study

BACKGROUND

Observational studies have shown a link between elevated body mass index (BMI) and the risk of polycystic ovary syndrome (PCOS). While Mendelian randomization (MR) studies in Europeans have suggested a causal role of increased BMI in PCOS, whether the same role is suggested in Asians has yet to be investigated. We used MR studies to infer causal effects using genetic data from East Asian populations.

METHODS AND FINDINGS

We performed a 2-sample bidirectional MR analysis using summary statistics from genome-wide association studies (GWAS) of BMI (with up to 173 430 individuals) and PCOS (4386 cases and 8017 controls) in East Asian populations. Seventy-eight single nucleotide polymorphisms (SNPs) correlated with BMI were selected as genetic instrumental variables to estimate the causal effect of BMI on PCOS using the inverse-variance weighted (IVW) method. To test the reliability of the results, further sensitivity analyses included MR-Egger regression, weighted median estimates, and leave-one-out analysis. The IVW analysis indicated a significant association between high BMI and the risk of PCOS (odds ratio per standard deviation higher BMI, 2.208; 95% confidence interval 1.537 to 3.168, P = 1.77 × 10-5). In contrast, the genetic risk of PCOS had no significant effect on BMI.

CONCLUSIONS

The results of our bidirectional MR study showed that an increase in BMI causes PCOS, while PCOS does not cause an increased BMI. This study provides further genetic support for a link between BMI and PCOS. Further research is needed to interpret the potential mechanisms of this association.

Brief mindfulness training for negative affectivity: A systematic review and meta-analysis

OBJECTIVE

Over the last 10 years, there has been a dramatic increase in published randomized controlled trials (RCTs) of brief mindfulness training (from single-session inductions to multisession interventions lasting up to 2 weeks), with some preliminary indications that these training programs may improve mental health outcomes, such as negative affectivity. This meta-analysis aimed to evaluate whether brief mindfulness training reliably reduces negative affectivity.

METHOD

PubMed, PsycINFO, and the Mindfulness Research Monthly Newsletter were systematically searched for brief mindfulness intervention RCTs assessing negative affectivity outcomes (e.g., depression, rumination, anxiety, stress). Sixty-five RCTs, including 5,489 participants predominantly without experience in meditation (64.64% female, mean age = 24.62), qualified for the meta-analytic review.

RESULTS

The meta-analysis revealed a small but significant effect of brief mindfulness training on reducing negative affectivity compared to control programs (g = .21, p < .001). The overall effect size was significantly moderated by participant characteristics: community samples (g = .41, p < .001) produced larger training effects compared to student samples (g = .14, p = .001; Qbetween p = .03). No significant effect size differences were found between clinical and nonclinical samples. However, when accounting for publication bias, the overall effect size of brief mindfulness training programs on negative affectivity was significantly reduced (g = .04).

CONCLUSIONS

Brief mindfulness training programs are increasingly popular approaches for reducing negative affectivity. This meta-analysis indicates that brief mindfulness training modestly reduces negative affectivity. Quantitative analyses indicated the presence of publication bias (i.e., unpublished null effect studies), highlighting the need to continue rigorous evaluation of brief mindfulness interventions. (PsycINFO Database Record

Challenges of developing and conducting clinical trials in rare disorders

Rare disease drug development is a rapidly expanding field. Clinical researchers in rare diseases face many challenges when conducting trials in small populations. Disease natural history is often poorly understood and the ability to detect clinically meaningful outcomes requires understanding of their rate of occurrence and variability, both of which contribute to difficulties in powering a study. Standard trial designs are not optimized to obtain adequate safety and efficacy data from small numbers of patients, so alternative designs (enrichment, crossover, adaptive, N-of 1) need to be considered. The affected patients can be hard to identify, especially early in the course of their disease, are generally geographically dispersed, and are often children. Trials are frequently conducted on an international scale and may be subject to complex or multiple regulatory agency oversights and may be affected by local customs, cultures, and practices. A basic understanding of the FDA programs supporting development of drugs for rare diseases is provided by this review and the role of early consultation with the FDA is emphasized. Of recent FDA New Molecular Entities (NME) approvals, 41% (17 approvals) in 2014, 47% (21 approvals) in 2015, and 41% (9 approvals) in 2016 were for rare disease indications. Through effective interactions and collaborations with physicians, institutions, and patient groups, sponsors have been successful in bringing new treatments to market for individuals affected by rare diseases. Challenges to drug development have been overcome through the focused efforts of patients/families, non-profit patient advocacy groups, drug developers, and regulatory authorities.

Surgery for the resolution of symptoms in malignant bowel obstruction in advanced gynaecological and gastrointestinal cancer

BACKGROUND

This is an update of the original Cochrane review published in Issue 4, 2000. Intestinal obstruction commonly occurs in progressive advanced gynaecological and gastrointestinal cancers. Management of these patients is difficult due to the patients' deteriorating mobility and function (performance status), the lack of further chemotherapeutic options, and the high mortality and morbidity associated with palliative surgery. There are marked variations in clinical practice concerning surgery in these patients between different countries, gynaecological oncology units and general hospitals, as well as referral patterns from oncologists under whom these patients are often admitted.

OBJECTIVES

To assess the efficacy of surgery for intestinal obstruction due to advanced gynaecological and gastrointestinal cancer.

SEARCH METHODS

We searched the following databases for the original review in 2000 and again for this update in June 2015: CENTRAL (2015, Issue 6); MEDLINE (OVID June week 1 2015); and EMBASE (OVID week 24, 2015).We also searched relevant journals, bibliographic databases, conference proceedings, reference lists, grey literature and the world wide web for the original review in 2000; we also used personal contact. This searching of other resources yielded very few additional studies. The Cochrane Pain, Palliative and Supportive Care Review Group no longer routinely handsearch journals. For these reasons, we did not repeat the searching of other resources for the June 2015 update.

SELECTION CRITERIA

As the review concentrates on the 'best evidence' available for the role of surgery in malignant bowel obstruction in known advanced gynaecological and gastrointestinal cancer we kept the inclusion criteria broad (including both prospective and retrospective studies) so as to include all studies relevant to the question. We sought published trials reporting on the effects of surgery for resolving symptoms in malignant bowel obstruction for adult patients with known advanced gynaecological and gastrointestinal cancer.

DATA COLLECTION AND ANALYSIS

We used data extraction forms to collect data from the studies included in the review. Two review authors extracted the data independently to reduce error. Owing to concerns about the risk of bias we decided not to conduct a meta-analysis of data and we have presented a narrative description of the study results. We planned to resolve disagreements by discussion with the third review author.

MAIN RESULTS

In total we have identified 43 studies examining 4265 participants. The original review included 938 patients from 25 studies. The updated search identified an additional 18 studies with a combined total of 3327 participants between 1997 and June 2015. The results of these studies did not change the conclusions of the original review.No firm conclusions can be drawn from the many retrospective case series so the role of surgery in malignant bowel obstruction remains controversial. Clinical resolution varies from 26.7% to over 68%, though it is often unclear how this is defined. Despite being an inadequate proxy for symptom resolution or quality of life, the ability to feed orally was a popular outcome measure, with success rates ranging from 30% to 100%. Rates of re-obstruction varied, ranging from 0% to 63%, though time to re-obstruction was often not included. Postoperative morbidity and mortality also varied widely, although again the definition of both of these surgical outcomes differed between many of the papers. There were no data available for quality of life. The reporting of adverse effects was variable and this has been described where available. Where discussed, surgical procedures varied considerably and outcomes were not reported by specific intervention. Using the 'Risk of bias' assessment tool, most included studies were at high risk of bias for most domains.

AUTHORS' CONCLUSIONS

The role of surgery in malignant bowel obstruction needs careful evaluation, using validated outcome measures of symptom control and quality of life scores. Further information could include re-obstruction rates together with the morbidity associated with the various surgical procedures.Currently, bowel obstruction is managed empirically and there are marked variations in clinical practice by different units. In order to compare outcomes in malignant bowel obstruction, there needs to be a greater degree of standardisation of management.Since the last version of this review none of the new included studies have provided additional information to change the conclusions.

Using a matrix-analytical approach to synthesizing evidence solved incompatibility problem in the hierarchy of evidence

OBJECTIVES

The hierarchy of evidence presupposes linearity and additivity of effects, as well as commutativity of knowledge structures. It thereby implicitly assumes a classical theoretical model.

STUDY DESIGN AND SETTING

This is an argumentative article that uses theoretical analysis based on pertinent literature and known facts to examine the standard view of methodology.

RESULTS

We show that the assumptions of the hierarchical model are wrong. The knowledge structures gained by various types of studies are not sequentially indifferent, that is, do not commute. External validity and internal validity are at least partially incompatible concepts. Therefore, one needs a different theoretical structure, typical of quantum-type theories, to model this situation. The consequence of this situation is that the implicit assumptions of the hierarchical model are wrong, if generalized to the concept of evidence in total.

CONCLUSION

The problem can be solved by using a matrix-analytical approach to synthesizing evidence. Here, research methods that produce different types of evidence that complement each other are synthesized to yield the full knowledge. We show by an example how this might work. We conclude that the hierarchical model should be complemented by a broader reasoning in methodology.

Statistical and methodological considerations for reporting RCTs in medical literature

Randomized controlled trials (RCTs) are known to provide the most reliable evidence on intervention. However, RCTs are often conducted and reported incompletely and inadequately, making readers and reviewers unable to judge the validity and reliability of the trials. In this article, we consider the statistical and methodological issues involved in reporting on RCTs, particularly in relation to the objectives, designs, and commencements of trials. This paper deals with the various issues that should be considered in presenting RCTs, and suggests checklists for reporting on them. We expect that these checklists will remind readers and reviewers to evaluate manuscripts systematically and comprehensively, making those manuscripts more transparent and reliable.

How Trustworthy Is the Scientific Literature in Industrial and Organizational Psychology?

The trustworthiness of research findings has been questioned in many domains of science. This article calls for a review of the trustworthiness of the scientific literature in industrial–organizational (I–O) psychology and a reconsideration of common practices that may harm the credibility of our literature. We note that most hypotheses in I–O psychology journals are confirmed. Thus, we are either approaching omniscience or our journals are publishing an unrepresentative sample of completed research. We view the latter explanation as more likely. We review structural problems in the publication process and in the conduct of research that is likely to promote a distortion of scientific knowledge. We then offer recommendations to make the I–O literature more accurate and trustworthy.

Randomized controlled trials 5: Determining the sample size and power for clinical trials and cohort studies

Performing well-powered randomized controlled trials is of fundamental importance in clinical research. The goal of sample size calculations is to assure that statistical power is acceptable while maintaining a small probability of a type I error. This chapter overviews the fundamentals of sample size calculation for standard types of outcomes for two-group studies. It considers (1) the problems of determining the size of the treatment effect that the studies will be designed to detect, (2) the modifications to sample size calculations to account for loss to follow-up and nonadherence, (3) the options when initial calculations indicate that the feasible sample size is insufficient to provide adequate power, and (4) the implication of using multiple primary endpoints. Sample size estimates for longitudinal cohort studies must take account of confounding by baseline factors.

Developing evidence-based dentistry skills: how to interpret randomized clinical trials and systematic reviews

Decision-making based on reliable evidence is more likely to lead to effective and efficient treatments. Evidence-based dentistry was developed, similarly to evidence-based medicine, to help clinicians apply current and valid research findings into their own clinical practice. Interpreting and appraising the literature is fundamental and involves the development of evidence-based dentistry (EBD) skills. Systematic reviews (SRs) of randomized controlled trials (RCTs) are considered to be evidence of the highest level in evaluating the effectiveness of interventions. Furthermore, the assessment of the report of a RCT, as well as a SR, can lead to an estimation of how the study was designed and conducted.

What If We Were Texas Sharpshooters? Predictor Reporting Bias in Regression Analysis

The author analyzes reporting biases in regression analyses. The consequences of researchers’ strategy to select significant predictors and omit nonsignificant predictors from regression analyses are examined, focusing on how this strategy—labeled the Texas sharpshooter (TS) approach—creates a predictor reporting bias (PRB) in primary studies and research syntheses. PRB was demonstrated in simulation studies when correlation coefficients from several primary regression studies with an underlying TS approach were aggregated in meta-analyses. Several important findings are noted. First, meta-analytical effect sizes of true effects can be overestimated because smaller, nonsignificant findings are omitted from regression models. Second, suppression effects of correlated predictor variables create biased effect size estimations for variables that are not related to the outcome. Finally, existing small effects are concealed, and between-study heterogeneity can be overestimated. Results show that PRB is contingent on sample size. While PRB is substantial in studies with small sample sizes ( N < 100), it is negligible when large sample sizes ( N > 500) are analyzed. Preconditions and remedies for reporting biases in regression analyses are discussed.

SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials

High quality protocols facilitate proper conduct, reporting, and external review of clinical trials. However, the completeness of trial protocols is often inadequate. To help improve the content and quality of protocols, an international group of stakeholders developed the SPIRIT 2013 Statement (Standard Protocol Items: Recommendations for Interventional Trials). The SPIRIT Statement provides guidance in the form of a checklist of recommended items to include in a clinical trial protocol. This SPIRIT 2013 Explanation and Elaboration paper provides important information to promote full understanding of the checklist recommendations. For each checklist item, we provide a rationale and detailed description; a model example from an actual protocol; and relevant references supporting its importance. We strongly recommend that this explanatory paper be used in conjunction with the SPIRIT Statement. A website of resources is also available (www.spirit-statement.org). The SPIRIT 2013 Explanation and Elaboration paper, together with the Statement, should help with the drafting of trial protocols. Complete documentation of key trial elements can facilitate transparency and protocol review for the benefit of all stakeholders.

CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials

Overwhelming evidence shows the quality of reporting of randomised controlled trials (RCTs) is not optimal. Without transparent reporting, readers cannot judge the reliability and validity of trial findings nor extract information for systematic reviews. Recent methodological analyses indicate that inadequate reporting and design are associated with biased estimates of treatment effects. Such systematic error is seriously damaging to RCTs, which are considered the gold standard for evaluating interventions because of their ability to minimise or avoid bias. A group of scientists and editors developed the CONSORT (Consolidated Standards of Reporting Trials) statement to improve the quality of reporting of RCTs. It was first published in 1996 and updated in 2001. The statement consists of a checklist and flow diagram that authors can use for reporting an RCT. Many leading medical journals and major international editorial groups have endorsed the CONSORT statement. The statement facilitates critical appraisal and interpretation of RCTs. During the 2001 CONSORT revision, it became clear that explanation and elaboration of the principles underlying the CONSORT statement would help investigators and others to write or appraise trial reports. A CONSORT explanation and elaboration article was published in 2001 alongside the 2001 version of the CONSORT statement. After an expert meeting in January 2007, the CONSORT statement has been further revised and is published as the CONSORT 2010 Statement. This update improves the wording and clarity of the previous checklist and incorporates recommendations related to topics that have only recently received recognition, such as selective outcome reporting bias. This explanatory and elaboration document-intended to enhance the use, understanding, and dissemination of the CONSORT statement-has also been extensively revised. It presents the meaning and rationale for each new and updated checklist item providing examples of good reporting and, where possible, references to relevant empirical studies. Several examples of flow diagrams are included. The CONSORT 2010 Statement, this revised explanatory and elaboration document, and the associated website (www.consort-statement.org) should be helpful resources to improve reporting of randomised trials.

Systematic reviews and meta-analysis: scientific rationale and interpretation

Systematic reviews represent a specific type of medical research in which the units of analysis are the original primary studies. They are essential tools in synthesizing available scientific information, increasing the validity of the conclusions of primary studies, and identifying areas for future research. They are also indispensable for the practice of evidence-based medicine and the medical decision-making process. However, conducting high quality systematic reviews is not easy and they can sometimes be difficult to interpret. This special article presents the rationale for carrying out and interpreting systematic reviews and uses a hypothetical example to draw attention to key-points.

Sample size calculation in physical medicine and rehabilitation: a systematic review of reporting, characteristics, and results in randomized controlled trials

OBJECTIVE

To assess systematically the reporting of sample size calculation in randomized controlled trials (RCTs) in 5 leading journals in the field of physical medicine and rehabilitation (PM&R).

DATA SOURCES

The data source was full reports of RCTs in 5 leading PM&R journals (Journal of Rehabilitation Medicine, Archives of Physical Medicine and Rehabilitation, American Journal of Physical Medicine and Rehabilitation, Clinical Rehabilitation, and Disability and Rehabilitation) between January and December of 1998 and 2008. Articles were identified in Medline.

STUDY SELECTION

A total of 111 articles met our inclusion criteria, which include RCTs of human studies in the 5 selected journals.

DATA EXTRACTION

Sample size calculation reporting and trial characteristics were collected for each trial by independent investigators.

DATA SYNTHESIS

In 2008, 57.3% of articles reported sample size calculation as compared with only 3.4% in 1998. The parameters that were commonly used were a power of 80% and alpha of 5%. Articles often failed to report effect size or effect estimates for sample size calculation. Studies reporting sample size calculation were more likely to describe the main outcome and to have a sample size greater than 50 subjects. The study outcome (positive vs negative) was not associated with the likelihood of sample size reporting. Trial characteristics of the 2 periods (1998 vs 2008) were similar except that in 1998 there were more negative studies compared with 2008.

CONCLUSIONS

Although sample size calculation reporting has improved dramatically in 10 years and is comparable with other fields in medicine, it is still not adequate given current publication guidelines.

Randomization in clinical trials in orthodontics: its significance in research design and methods to achieve it

Randomization is a key step in reducing selection bias during the treatment allocation phase in randomized clinical trials. The process of randomization follows specific steps, which include generation of the randomization list, allocation concealment, and implementation of randomization. The phenomenon in the dental and orthodontic literature of characterizing treatment allocation as random is frequent; however, often the randomization procedures followed are not appropriate. Randomization methods assign, at random, treatment to the trial arms without foreknowledge of allocation by either the participants or the investigators thus reducing selection bias. Randomization entails generation of random allocation, allocation concealment, and the actual methodology of implementing treatment allocation randomly and unpredictably. Most popular randomization methods include some form of restricted and/or stratified randomization. This article introduces the reasons, which make randomization an integral part of solid clinical trial methodology, and presents the main randomization schemes applicable to clinical trials in orthodontics.

Systematic review and cost analysis comparing use of chlorhexidine with use of iodine for preoperative skin antisepsis to prevent surgical site infection

OBJECTIVE

To compare use of chlorhexidine with use of iodine for preoperative skin antisepsis with respect to effectiveness in preventing surgical site infections (SSIs) and cost.

METHODS

We searched the Agency for Healthcare Research and Quality website, the Cochrane Library, Medline, and EMBASE up to January 2010 for eligible studies. Included studies were systematic reviews, meta-analyses, or randomized controlled trials (RCTs) comparing preoperative skin antisepsis with chlorhexidine and with iodine and assessing for the outcomes of SSI or positive skin culture result after application. One reviewer extracted data and assessed individual study quality, quality of evidence for each outcome, and publication bias. Meta-analyses were performed using a fixed-effects model. Using results from the meta-analysis and cost data from the Hospital of the University of Pennsylvania, we developed a decision analytic cost-benefit model to compare the economic value, from the hospital perspective, of antisepsis with iodine versus antisepsis with 2 preparations of chlorhexidine (ie, 4% chlorhexidine bottle and single-use applicators of a 2% chlorhexidine gluconate [CHG] and 70% isopropyl alcohol [IPA] solution), and also performed sensitivity analyses.

RESULTS

Nine RCTs with a total of 3,614 patients were included in the meta-analysis. Meta-analysis revealed that chlorhexidine antisepsis was associated with significantly fewer SSIs (adjusted risk ratio, 0.64 [95% confidence interval, [0.51-0.80]) and positive skin culture results (adjusted risk ratio, 0.44 [95% confidence interval, 0.35-0.56]) than was iodine antisepsis. In the cost-benefit model baseline scenario, switching from iodine to chlorhexidine resulted in a net cost savings of $16-$26 per surgical case and $349,904-$568,594 per year for the Hospital of the University of Pennsylvania. Sensitivity analyses showed that net cost savings persisted under most circumstances.

CONCLUSIONS

Preoperative skin antisepsis with chlorhexidine is more effective than preoperative skin antisepsis with iodine for preventing SSI and results in cost savings.

An assessment of quality characteristics of randomised control trials published in dental journals

OBJECTIVES

The purpose of this study was to investigate the quality of reporting of randomised clinical trials (RCTs) published in dental specialty journals.

METHODS

The journals possessing the highest impact factor (2008 data) in the six major dental specialties were included in the study. The contents of the 24 most recent issues of each journal were hand-searched and research articles identified as randomised controlled trials (RCTs) were selected. Quality evaluation was performed using the modified Consolidated Standards of Reporting Trials (CONSORT) statement checklist. The data were analysed using descriptive statistics followed by univariate and multivariate examination of statistical associations (alpha=0.05).

RESULTS

Ninety-five RCTs were identified with generally suboptimal scores on quality reporting on key CONSORT areas. Significant differences were found among journals with the Journal of Clinical Periodontology achieving the highest score, followed by the American Journal of Orthodontics and Dentofacial Orthopedics. There was a positive association between quality score and number of authors, involvement of statistician/epidemiologist, and multicentre trials.

CONCLUSIONS

The quality scores of RCTs in major dental journals are considered suboptimal in key CONSORT areas. This receives critical importance considering that improved quality of RCTs is a fundamental prerequisite for improved dental care.

An Empirical Assessment of Meta-Analytic Practice

In the three decades after the publication of the first meta-analyses in the behavioral sciences, hundreds of articles and a number of technical guides have emerged concerning meta-analytic practice and reporting standards. The purpose of the present study is to review the practice and reporting standards of a random sample of published meta-analyses ( n = 100) in psychology and related disciplines in the decade from 1994 through 2004. We focus on practice and reporting at each stage of the meta-analytic process and explore differences between psychological subdisciplines. These findings suggest that the practice of meta-analysis in the last decade has not yet converged on a set of common standards, though some expert recommendations are beginning to be heeded. Authors should be attentive to proper procedure and reporting in light of the numerous threats to the validity of a meta-analysis. Ironically, even though meta-analysts often struggle with incomplete or inconsistent reporting in primary research they are themselves not entirely consistent in reporting their methods and results.

Randomized controlled trials in plastic surgery: a 20-year review of reporting standards, methodologic quality, and impact

BACKGROUND

Randomized controlled trials in plastic surgery have not been analyzed comprehensively. We analyzed plastic surgical randomized controlled trials with respect to reporting standards, methodologic quality, and impact on the specialty.

METHODS

Randomized controlled trials published from 1986 to 2006 in three major plastic surgery journals were scored for quality and impact using the Consolidated Standards of Reporting Trials checklist, the Jadad criteria, citation numbers, and other parameters. The associations between the quality scores and multiple independent parameters, including trial impact, were explored. The relative impact of randomized controlled trials in plastic surgery was compared with that in other specialties.

RESULTS

A total of 163 randomized controlled trials were evaluated. The average Consolidated Standards of Reporting Trials and Jadad scores were 49 percent and 2.3, respectively. There were deficiencies in the reporting of parameters that influence bias and statistical significance. Randomized controlled trials with high impact or high methodologic quality had higher reporting scores. However, the quality and impact scores did not correlate with the number of participants, subject category, country of origin, or year or journal of publication. Nonsurgical trials had significantly higher quality and impact than surgical trials. Randomized controlled trials in plastic surgery had relatively lower impact as compared with randomized controlled trials in other specialties.

CONCLUSIONS

The reporting and methodologic standards of randomized controlled trials in plastic surgery need improvement. Standards could be improved if well-accepted reporting and methodologic criteria are considered when designing and evaluating randomized controlled trials. Instituting higher standards may improve the impact of randomized controlled trials and make them more influential in plastic surgery.

The effectiveness of self help technologies for emotional problems in adolescents: a systematic review

BACKGROUND

Adolescence is a transition period that involves physiological, psychological, and social changes. Emotional problems such as symptoms of anxiety and depression may develop due to these changes. Although many of these problems may not meet diagnostic thresholds, they may develop into more severe disorders and may impact on functioning. However, there are barriers that may make it difficult for adolescents to receive help from health professionals for such problems, one of which is the limited availability of formal psychological therapy. One way of increasing access to help for such problems is through self help technology (i.e. delivery of psychological help through information technology or paper based formats). Although there is a significant evidence base concerning self help in adults, the evidence base is much weaker in adolescents. This study aims to examine the effectiveness of self help technology for the treatment of emotional problems in adolescents by conducting a systematic review of randomized and quasi-experimental evidence.

METHODS

Five major electronic databases were searched: Medline, PsycInfo, Embase, Cochrane Controlled Trials Register and CINAHL. In addition, nine journals were handsearched and the reference lists of all studies were examined for any additional studies. Fourteen studies were identified. Effect sizes were calculated across 3 outcome measures: attitude towards self (e.g. self esteem); social cognition (e.g. self efficacy); and emotional symptoms (i.e. depression and anxiety symptoms).

RESULTS

Meta analysis showed small, non-significant effect size for attitude towards self (ES = -0.14, 95% CI = -0.72 to 0.43), a medium, non-significant effect size for social cognition (ES = -0.49, 95% CI = -1.23 to 0.25) and a medium, non-significant effect size for emotional symptoms (ES = -0.47, 95% CI = -1.00 to 0.07). However, these findings must be considered preliminary, because of the small number of studies, their heterogeneity, and the relatively poor quality of the studies.

CONCLUSION

At present, the adoption of self help technology for adolescents with emotional problems in routine clinical practice cannot be recommended. There is a need to conduct high quality randomised trials in clearly defined populations to further develop the evidence base before implementation.

Controlled trials in aesthetic plastic surgery: a 16-year analysis

Aesthetic surgery is one pillar of plastic surgery. Thus, not surprisingly, journals exist that focus predominantly on advances within this subspecialty. However, rarely has the process of systematic reviewing that identified randomized controlled trials (RCTs) and controlled clinical trials (CCTs) been conducted within this subspecialty. All original articles published in Aesthetic Plastic Surgery were analyzed to identify all RCTs and CCTs. The proportion of RCTs and CCTs in all original articles was determined, and the quality of reporting was assessed on the basis of established quality items. Additional parameters were investigated including reporting of statistically significant differences, type of institution, and country affiliation of the first author. Of the 1,048 original articles analyzed, 11 (1%) and 24 (2.3%) articles met the inclusion criteria for RCTs and CCTs, respectively. Only two studies were single blinded, whereas only one study reported on successful double blinding and appropriate allocation concealment. Notably, these trials were RCTs. Participant dropout was reported in one study. Statistically significant differences were reported in 18 trials, 6 of which were RCTs. The annual publication of RCTs has increased over the past 5 years. North America and Europe contributed a total of 28 controlled trials (80%). Controlled trials are being conducted in aesthetic surgery at a strikingly low rate. However, a recent increase in published RCTs reflects the recognition that performing outcome studies is pivotal in moving practice toward a foundation based on assessment by outcome. The quality of reporting, however, needs improvement.

Transition from congress abstract to full publication for clinical trials presented at laser meetings

The present study aims to identify (1) what proportion of abstracts of clinical trials presented at The American Society for Laser Medicine and Surgery (ASLMS) annual meetings are published as full reports, (2) time to publication, and (3) factors that may predict the publication of research in peer-reviewed journals. Two investigators independently hand-searched all abstracts of the ASLMS meetings to identify all reports of clinical trials. Details of sample size, the country of origin, topic of research, type of presentation, type of laser, direction of outcome, and statistical significance were recorded for each abstract. To determine the full publication status of each study, The Cochrane Central Register of Controlled Trials, PubMed, and EMBASE was searched. A total of 198 abstracts were identified. Of these, 87 abstracts (44%) have been fully published. The average time from presentation at the meeting to full publication was 57 months (95% confidence interval = 52-61), and the estimated rate of abstracts published at 1, 2, and 4 years was 15, 30, and 38%, respectively. There is significant tendency for being fully published in high-power laser studies, with USA as country of origin, and orally presented. Our findings supports this opinion that conference abstracts can be an important source for systematic reviews and failure to identify trials presented in congresses might threaten the validity of systematic reviews.

Recombinant LH supplementation to recombinant FSH during induced ovarian stimulation in the GnRH-antagonist protocol: a meta-analysis

This study aims to compare the efficacy of recombinant LH (rLH) supplementation for ovarian stimulation in gonadotrophin-releasing hormone-antagonist protocol for IVF/intracytoplasmic sperm injection cycles. Search strategies included online surveys of databases. The fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Five trials fulfilled the inclusion criteria. When the meta-analysis was carried out, advantages were observed for the LH supplementation protocol with respect to higher serum oestradiol concentrations on the day of human chorionic gonadotrophin administration P < 0.0001; WMD: 514, 95% CI 368, 660) and higher number of mature oocytes (P = 0.0098; WMD: 0.88, 95% CI 0.21, 1.54). However, these differences were not observed in the total amount of recombinant FSH (rFSH) administered, days of stimulation, number of oocyets retrieved, the clinical pregnancy rate per oocyte retrieval, the implantation rate and miscarriage rate. This result demonstrates that the association of rLH with rFSH may prevent any decrease in oestradiol after antagonist administration and that a significantly higher number of mature oocytes was available for laboratory work. Nevertheless, it failed to show any statistically significant difference in clinically significant end-points in IVF (implantation and pregnancy rates). Additional randomized controlled trials are needed to confirm these results further.

Improving Cognition and Function Through Exercise Intervention in Alzheimer's Disease

PURPOSE

To analyze the effects of cognition on function and to explore the potential of aerobic exercise for promoting cognitive and functional capacities.

DESIGN

Integrative review of literature.

METHODS

Studies were selected based on an extensive search of electronic databases and manual cross-referencing for 1980 to 2006, using the combination of key words: Alzheimer's disease (AD), dementia, or cognitive impairment with function or activities of daily living.

FINDINGS

Three broad themes were identified from the literature analysis. First, global cognition has mainly been used to examine the effect of cognition on function, indicating an assumption that functional decline progresses in a hierarchical manner in AD. Second, specific cognitive domains affect functional decline in different ways. Executive functioning might have more effect on function than does memory. Third, aerobic exercise might promote cognitive and functional capacities in people with AD by modifying neuropathological changes in the brain.

CONCLUSIONS

Specific cognitive domains such as executive functioning are important for understanding function in people with AD and are potentially modifiable by aerobic exercise.

Risk of mortality and cardiovascular disease associated with the ankle-brachial index: Systematic review

OBJECTIVE

To determine the strength and consistency with which a low ankle brachial pressure index (ABI), measured in the general population, is associated with an increased risk of subsequent death and/or cardiovascular events.

DESIGN

Systematic review.

DATA SOURCES

Medline, Embase, reference lists and grey literature were searched; studies known to experts were also retrieved.

MAIN OUTCOME MEASURES

All cause mortality, fatal and non-fatal coronary heart disease and stroke.

REVIEW METHODS

Longitudinal studies in which participants were representative of the general population (all ages, either sex) and which used any standard method for measurement and calculation of the ABI. Studies in which participants were selected according to presence of pre-existing disease or were post intervention (e.g. angioplasty or peripheral arterial grafting) were excluded.

RESULTS

11 studies comprising 44,590 subjects from six different countries were included. Despite clinical heterogeneity between studies, the findings were remarkably consistent in demonstrating an increased risk of clinical cardiovascular disease associated with a low ABI. A low ABI (<0.9) was associated with an increased risk of subsequent all cause mortality (pooled RR 1.60, 95% CI 1.32-1.95), cardiovascular mortality (pooled RR 1.96, 95% CI 1.46-2.64), coronary heart disease (pooled RR 1.45, 95% CI 1.08-1.93) and stroke (pooled RR 1.35, 95% CI 1.10-1.65) after adjustment for age, sex, conventional cardiovascular risk factors and prevalent cardiovascular disease.

CONCLUSIONS

The ABI may help to identify asymptomatic individuals in the general population who are at increased risk of subsequent cardiovascular events. Evaluation is now required of the potential of incorporating ABI measurement into cardiovascular prevention programmes.

Meta-analysis of data from the six primary prevention trials of cardiovascular events using aspirin

Until recently, 5 major studies have formed the basis for the use of aspirin (acetylsalicylic acid) in primary prevention of cardiovascular (CV) events. Despite these data, the role of aspirin in primary prevention has not been established firmly. Six randomized trials have evaluated the benefits of aspirin for the primary prevention of CV events: the British Doctors' Trial, the Physicians' Health Study, the Thrombosis Prevention Trial, the Hypertension Optimal Treatment study, the Primary Prevention Project, and the Women's Health Study. The combined sample consists of 47,293 subjects on aspirin and 45,580 not on aspirin or placebo. A meta-analysis of these 6 trials assessed 6 CV end points: total coronary heart disease (CHD), nonfatal myocardial infarction (MI), total CV events, stroke, CV mortality, and all-cause mortality. No covariate adjustment was performed and appropriate tests for treatment effect, heterogeneity, and study size bias were applied. Using odds ratios and confidence intervals, the meta-analysis suggested superiority of aspirin for total CHD, nonfatal MI, and total CV events (p < or =0.001 in each case), with a nonsignificant trend (0.07 < p <0.34) for decreased risk of stroke, CV mortality, and all-cause mortality. There was no evidence of statistical bias (p >0.05). Given the study size and cohort, aspirin decreased the risk of CV events in this large patient sample. In conclusion, primary prevention with aspirin decreased the risk of total CHD, nonfatal MI, and total CV events, but there were no significant differences in the incidences of stroke or CV mortality.