A meta-analysis of clinical trials involving different classifications of response into ordered categories

Mindfulness-enhanced parenting programmes for improving the psychosocial outcomes of children (0 to 18 years) and their parents

BACKGROUND

Emotional and behavioural difficulties (EBD) in children are common, characterised by externalising or internalising behaviours that can be highly stable over time. EBD are an important cause of functional disability in childhood, and predictive of poorer psychosocial, academic, and occupational functioning into adolescence and adulthood. The prevalence, stability, and long-term consequences of EBD highlight the importance of intervening in childhood when behavioural patterns are more easily modified. Multiple factors contribute to the aetiology of EBD in children, and parenting plays an important role. The relationship between parenting and EBD has been described as bidirectional, with parents and children shaping one another's behaviour. One consequence of bidirectionality is that parents with insufficient parenting skills may become involved in increasingly negative behaviours when dealing with non-compliance in children. This can have a cyclical effect, exacerbating child behavioural difficulties and further increasing parental distress. Behavioural or skills-based parenting training can be highly effective in addressing EBD in children. However, emotional dysregulation may intercept some parents' ability to implement parenting skills, and there is recognition that skills-based interventions may benefit from adjunct components that better target parental emotional responses. Mindful parenting interventions have demonstrated some efficacy in improving child outcomes via improvements in parental emotion regulation, and there is potential for mindfulness training to enhance the effectiveness of standard parent training programmes.

OBJECTIVES

To assess the effectiveness of mindfulness-enhanced parent training programmes on the psychosocial functioning of children (aged 0 to 18 years) and their parents.

SEARCH METHODS

We searched the following databases up to April 2023: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL Plus, PsycINFO, Sociological Abstracts, Social Sciences Citation Index, Conference Proceedings Citation Index - Social Science & Humanities, AMED, ERIC, ProQuest Dissertations & Theses, Cochrane Database of Systematic Reviews, Campbell Collaboration Library of Systematic Reviews, as well as the following trials registers: ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP). We also contacted organisations/experts in the field.

SELECTION CRITERIA

We included randomised and quasi-randomised trials. Participants were parents or caregivers of children under the age of 18. The intervention was mindfulness-enhanced parent training programmes compared with a no-intervention, waitlist, or attentional control, or a parent training programme with no mindfulness component. The intervention must have combined mindfulness parent training with behavioural or skills-based parent training. We defined parent training programmes in terms of the delivery of a standardised and manualised intervention over a specified and limited period, on a one-to-one or group-basis, with a well-defined mindfulness component. The mindfulness component must have included mindfulness training (breath, visualisation, listening, or other sensory focus) and an explicit focus on present-focused attention and non-judgemental acceptance.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane procedures.

MAIN RESULTS

Eleven studies met our inclusion criteria, including one ongoing study. The studies compared a mindfulness-enhanced parent training programme with a no-treatment, waitlist, or attentional control (2 studies); a parent training programme with no mindfulness component (5 studies); both a no-treatment, waitlist, or attentional control and a parent training programme with no mindfulness component (4 studies). We assessed all studies as being at an unclear or high risk of bias across multiple domains. We pooled child and parent outcome data from 2118 participants to produce effect estimates. No study explicitly reported on self-compassion, and no adverse effects were reported in any of the studies. Mindfulness-enhanced parent training programmes compared to a no-treatment, waitlist, or attentional control Very low certainty evidence suggests there may be a small to moderate postintervention improvement in child emotional and behavioural adjustment (standardised mean difference (SMD) -0.46, 95% confidence interval (CI) -0.96 to 0.03; P = 0.06, I2 = 62%; 3 studies, 270 participants); a small improvement in parenting skills (SMD 0.22, 95% CI 0.06 to 0.39; P = 0.008, I2 = 0%; 3 studies, 587 participants); and a moderate decrease in parental depression or anxiety (SMD -0.50, 95% CI -0.96 to -0.04; P = 0.03; 1 study, 75 participants). There may also be a moderate to large decrease in parenting stress (SMD -0.79, 95% CI -1.80 to 0.23; P = 0.13, I2 = 82%; 2 studies, 112 participants) and a small improvement in parent mindfulness (SMD 0.21, 95% CI -0.14 to 0.56; P = 0.24, I2 = 69%; 3 studies, 515 participants), but we were not able to exclude little to no effect for these outcomes. Mindfulness-enhanced parent training programmes compared to parent training with no mindfulness component Very low certainty evidence suggests there may be little to no difference postintervention in child emotional and behavioural adjustment (SMD -0.09, 95% CI -0.58 to 0.40; P = 0.71, I2 = 64%; 5 studies, 203 participants); parenting skills (SMD 0.13, 95% CI -0.16 to 0.42; P = 0.37, I2 = 16%; 3 studies, 319 participants); and parent mindfulness (SMD 0.11, 95% CI -0.19 to 0.41; P = 0.48, I2 = 44%; 4 studies, 412 participants). There may be a slight decrease in parental depression or anxiety (SMD -0.24, 95% CI -0.83 to 0.34; P = 0.41; 1 study, 45 participants; very low certainty evidence), though we cannot exclude little to no effect, and a moderate decrease in parenting stress (SMD -0.51, 95% CI -0.84 to -0.18; P = 0.002, I2 = 2%; 3 studies, 150 participants; low certainty evidence).

AUTHORS' CONCLUSIONS

Mindfulness-enhanced parenting training may improve some parent and child outcomes, with no studies reporting adverse effects. Evidence for the added value of mindfulness training to skills-based parenting training programmes is suggestive at present, with moderate reductions in parenting stress. Given the very low to low certainty evidence reviewed here, these estimates will likely change as more high-quality studies are produced.

Does the Lingual-Based Mucoperiosteal Flap Reduce Postoperative Morbidity Compared With the Buccal-Based Mucoperiosteal Flap After the Surgical Removal of Impacted Third Molars? A Meta-analysis Review

PURPOSE

The lingual-based mucoperiosteal flap, a novel flap, was unclear about the effects on the prognosis of surgery for impacted mandibular third molars. This study aimed to compare the lingual- and buccal-based mucoperiosteal flaps with respect to postoperative responses and complications.

MATERIALS AND METHODS

A systematic review with a meta-analysis was designed and the PubMed, Cochrane Library, EMBASE, and Web of Science databases and Google Scholar from January 1, 2000 to April 30, 2020 were searched for randomized clinical trials. The predictor variable was buccal- or lingual-based flap in the surgery, and the outcome variables were pain, swelling, trismus, operative time, and wound dehiscence. Other study variables were sex and retention depth of impacted teeth. RevMan 5.3 software was used for data analysis. Mean differences or standardized mean differences and risk ratios were computed to assess associations between 2 variables, where statistical significance was set at P < .05.

RESULTS

Seven publications met the inclusion criteria, contributing 370 subjects who had 590 teeth removed to sample. The lingual-based flap failed to significantly reduce postoperative discomfort. However, subgroup analysis revealed that subjects who underwent comma flap (a type of lingual-based flap) surgeries complained of milder pain than those who underwent buccal-based flap surgeries on day 1 (mean difference = -1.18, 95% confidence interval [CI] [-1.53, -0.83], P < .001) and day 7 (mean difference = -1.80, 95% CI [-2.13, -1.48], P < .001) after surgery. Significant differences were also observed on days 1, 3, and 7 regarding postoperative swelling and trismus (P < .01). In addition, the lingual-based flap was reported to cause a significantly lower rate of wound dehiscence (relative risk = 0.46, 95% CI [0.30, 0.69], P = .0002).

CONCLUSIONS

The lingual-based flap was associated with better primary wound closure in third molar removal. The comma flap, as a subtype, was preferable for relieving postoperative pain, swelling, and trismus over the buccal-based flap.

Interventions to Improve the Response of Professionals to Children Exposed to Domestic Violence and Abuse: A Systematic Review

Exposure of children to domestic violence and abuse (DVA) is a form of child maltreatment with short- and long-term behavioural and mental health impact. Health care professionals are generally uncertain about how to respond to domestic violence and are particularly unclear about best practice with regards to children's exposure and their role in a multiagency response. In this systematic review, we report educational and structural or whole-system interventions that aim to improve professionals' understanding of, and response to, DVA survivors and their children. We searched 22 bibliographic databases and contacted topic experts for studies reporting quantitative outcomes for any type of intervention aiming to improve professional responses to disclosure of DVA with child involvement. We included interventions for physicians, nurses, social workers and teachers. Twenty-one studies met the inclusion criteria: three randomised controlled trials (RCTs), 18 pre-post intervention surveys. There were 18 training and three system-level interventions. Training interventions generally had positive effects on participants' knowledge, attitudes towards DVA and clinical competence. The results from the RCTs were consistent with the before-after surveys. Results from system-level interventions aimed to change organisational practice and inter-organisational collaboration demonstrates the benefit of coordinating system change in child welfare agencies with primary health care and other organisations. Implications for policy and research are discussed. © 2015 The Authors. Child Abuse Review published by John Wiley & Sons Ltd. 'We searched 22 bibliographic databases and contacted topic experts'.

KEY PRACTITIONER MESSAGES

We reviewed published evidence on interventions aimed at improving professionals' practice with domestic violence survivors and their children.Training programmes were found to improve participants' knowledge, attitudes and clinical competence up to a year after delivery.Key elements of successful training include interactive discussion, booster sessions and involving specialist domestic violence practitioners.Whole-system approaches aiming to promote coordination and collaboration across agencies appear promising but require funding and high levels of commitment from partners. 'Training programmes were found to improve participants' knowledge, attitudes and clinical competence up to a year after delivery'.

The Missing Medians: Exclusion of Ordinal Data from Meta-Analyses

BACKGROUND

Meta-analyses are considered the gold standard of evidence-based health care, and are used to guide clinical decisions and health policy. A major limitation of current meta-analysis techniques is their inability to pool ordinal data. Our objectives were to determine the extent of this problem in the context of neurological rating scales and to provide a solution.

METHODS

Using an existing database of clinical trials of oral neuroprotective therapies, we identified the 6 most commonly used clinical rating scales and recorded how data from these scales were reported and analysed. We then identified systematic reviews of studies that used these scales (via the Cochrane database) and recorded the meta-analytic techniques used. Finally, we identified a statistical technique for calculating a common language effect size measure for ordinal data.

RESULTS

We identified 103 studies, with 128 instances of the 6 clinical scales being reported. The majority- 80%-reported means alone for central tendency, with only 13% reporting medians. In analysis, 40% of studies used parametric statistics alone, 34% of studies employed non-parametric analysis, and 26% did not include or specify analysis. Of the 60 systematic reviews identified that included meta-analysis, 88% used mean difference and 22% employed difference in proportions; none included rank-based analysis. We propose the use of a rank-based generalised odds ratio (WMW GenOR) as an assumption-free effect size measure that is easy to compute and can be readily combined in meta-analysis.

CONCLUSION

There is wide scope for improvement in the reporting and analysis of ordinal data in the literature. We hope that adoption of the WMW GenOR will have the dual effect of improving the reporting of data in individual studies while also increasing the inclusivity (and therefore validity) of meta-analyses.

Efficacy and safety of pharmacological treatments for neuroborreliosis--protocol for a systematic review

BACKGROUND

Neuroborreliosis is a tick-borne infectious disease of the nervous system caused by Borrelia burgdorferi. Common clinical manifestations of neuroborreliosis are cranial nerve dysfunctions, polyradiculoneuritis, and meningitis. Diagnosis is usually based on clinical presentation, serologic testing, and analysis of cerebrospinal fluid. Many aspects of pharmacological treatment, such as choice of drug, dosage, and duration are subject of intense debate, leading to uncertainties in patients and healthcare providers alike. To approach the questions regarding pharmacological treatment of neuroborreliosis, we will perform a systematic review.

METHODS

We will perform a comprehensive systematic literature search for potentially eligible studies that report outcomes after pharmacological interventions. To adequately consider the wealth of research that has been conducted so far, this review will evaluate randomized controlled trials (RCTs) and non-randomized studies on treatment of neuroborreliosis. We will assess potential risk of bias for each RCT meeting our selection criteria using the Cochrane risk of bias tool for RCTs. For non-randomized studies, we will use the Newcastle-Ottawa Scale and the recently piloted Cochrane risk of bias tool for non-randomized studies. Our primary outcome of interest will be neurological symptoms and the secondary outcomes will be disability, patient-reported outcomes (quality of life, and, if reported separately from other neurological symptoms, pain, fatigue, depression, cognition, and sleep), adverse events, and cerebrospinal fluid pleocytosis. Pooling of data and meta-analysis will only be deemed justified between studies with similar design (e.g., RCTs are only combined with other RCTs), characteristics (e.g., similar populations), and of acceptable heterogeneity (I2 < 80%). Pooled estimates will be calculated using RevMan software. Prespecified subgroup analyses will evaluate groups of antibiotics, length of antibiotic treatment, and different doses of doxycycline. We will assess the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

DISCUSSION

This systematic review will summarize the available evidence from RCTs and non-randomized studies regarding pharmacological treatment of neuroborreliosis. The available evidence will be summarized and discussed to provide a basis for decision-making for patients and healthcare professionals.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number: CRD42014008839.

Parent training interventions for Attention Deficit Hyperactivity Disorder (ADHD) in children aged 5 to 18 years

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterised by high levels of inattention, hyperactivity and impulsivity that are present before the age of seven years, seen in a range of situations, inconsistent with the child's developmental level and causing social or academic impairment. Parent training programmes are psychosocial interventions aimed at training parents in techniques to enable them to manage their children's challenging behaviour.

OBJECTIVES

To determine whether parent training interventions are effective in reducing ADHD symptoms and associated problems in children aged between five and eigtheen years with a diagnosis of ADHD, compared to controls with no parent training intervention.

SEARCH METHODS

We searched the following electronic databases (for all available years until September 2010): CENTRAL (2010, Issue 3), MEDLINE (1950 to 10 September 2010), EMBASE (1980 to 2010 Week 36), CINAHL (1937 to 13 September 2010), PsycINFO (1806 to September Week 1 2010), Dissertation Abstracts International (14 September 2010) and the metaRegister of Controlled Trials (14 September 2010). We contacted experts in the field to ask for details of unpublished or ongoing research.

SELECTION CRITERIA

Randomised (including quasi-randomised) studies comparing parent training with no treatment, a waiting list or treatment as usual (adjunctive or otherwise). We included studies if ADHD was the main focus of the trial and participants were over five years old and had a clinical diagnosis of ADHD or hyperkinetic disorder that was made by a specialist using the operationalised diagnostic criteria of the DSM-III/DSM-IV or ICD-10. We only included trials that reported at least one child outcome.

DATA COLLECTION AND ANALYSIS

Four authors were involved in screening abstracts and at least 2 authors looked independently at each one. We reviewed a total of 12,691 studies and assessed five as eligible for inclusion. We extracted data and assessed the risk of bias in the five included trials. Opportunities for meta-analysis were limited and most data that we have reported are based on single studies.

MAIN RESULTS

We found five studies including 284 participants that met the inclusion criteria, all of which compared parent training with de facto treatment as usual (TAU). One study included a nondirective parent support group as a second control arm.  Four studies targeted children's behaviour problems and one assessed changes in parenting skills. Of the four studies targeting children's behaviour, two focused on behaviour at home and two focused on behaviour at school. The two studies focusing on behaviour at home had different findings: one found no difference between parent training and treatment as usual, whilst the other reported statistically significant results for parent training versus control. The two studies of behaviour at school also had different findings: one study found no difference between groups, whilst the other reported positive results for parent training when ADHD was not comorbid with oppositional defiant disorder. In this latter study, outcomes were better for girls and for children on medication.We assessed the risk of bias in most of the studies as unclear at best and often as high. Information on randomisation and allocation concealment did not appear in any study report. Inevitably, blinding of participants or personnel was impossible for this intervention; likewise, blinding of outcome assessors (who were most often the parents who had delivered the intervention) was impossible.We were only able to conduct meta-analysis for two outcomes: child 'externalising' behaviour (a measure of rulebreaking, oppositional behaviour or aggression) and child 'internalising' behaviour (for example, withdrawal and anxiety). Meta-analysis of three studies (n = 190) providing data on externalising behaviour produced results that fell short of statistical significance (SMD -0.32; 95% CI -0.83 to 0.18, I(2) = 60%). A meta-analysis of two studies (n = 142) for internalising behaviour gave significant results in the parent training groups (SMD -0.48; 95% CI -0.84 to -0.13, I(2) = 9%). Data from a third study likely to have contributed to this outcome were missing, and we have some concerns about selective outcome reporting bias.Individual study results for child behaviour outcomes were mixed. Positive results on an inventory of child behaviour problems were reported for one small study (n = 24) with the caveat that results were only positive when parent training was delivered to individuals and not groups. In another study (n = 62), positive effects (once results were adjusted for demographic and baseline data) were reported for the intervention group on a social skills measure.The study (n = 48) that assessed parenting skill changes compared parent training with a nondirective parent support group. Statistically significant improvements were reported for the parent training group. Two studies (n = 142) provided data on parent stress indices that were suitable for combining in a meta-analysis. The results were significant for the 'child' domain (MD -10.52; 95% CI -20.55 to -0.48) but not the 'parent' domain (MD -7.54; 95% CI -24.38 to 9.30). Results for this outcome from a small study (n = 24) suggested a long-term benefit for mothers who received the intervention at an individual level; in contrast, fathers benefited from short-term group treatment. A fourth study reported change data for within group measures of parental stress and found significant benefits in only one of the two active parent training group arms (P ≤ 0.01).No study reported data for academic achievement, adverse events or parental understanding of ADHD.

AUTHORS' CONCLUSIONS

Parent training may have a positive effect on the behaviour of children with ADHD. It may also reduce parental stress and enhance parental confidence. However, the poor methodological quality of the included studies increases the risk of bias in the results. Data concerning ADHD-specific behaviour are ambiguous. For many important outcomes, including school achievement and adverse effects, data are lacking.Evidence from this review is not strong enough to form a basis for clinical practice guidelines. Future research should ensure better reporting of the study procedures and results.

Analysis of an ordinal outcome in a multicentric randomized controlled trial: application to a 3- arm anti- malarial drug trial in Cameroon

Background

Malaria remains a burden in Sub-Saharan Countries. The strategy proposed by the World Health Organization (WHO) is to systematically compare the therapeutic efficacy of antimalarial drugs using as primary outcome for efficacy, a four-category ordered criterion. The objective of the present work was to analyze the treatment effects on this primary outcome taking into account both a center-effect and individual covariates. A three-arm, three-centre trial of Amodiaquine (AQ), sulfadoxine-pyrimethamine (SP) and their combination (AQ + SP), conducted by OCEAC-IRD in 2003, in 538 children with uncomplicated Plasmodium falciparum malaria, is used as an illustration.

Methods

Analyses were based on ordinal regression methods, assuming an underlying continuous latent variable, using either the proportional odds (PO) or the proportional hazards (PH) models. Different algorithms, corresponding to both frequentist- and bayesian-approaches, were implemented using the freely available softwares R and Winbugs, respectively. The performances of the different methods were evaluated on a simulated data set, and then they were applied on the trial data set.

Results

Good coverage probability and type-1 error for the treatment effect were achieved. When the methods were applied on the trial data set, results highlighted a significance decrease of SP efficacy when compared to AQ (PO, odds ratio [OR] 0.14, 95% confidence interval [CI] 0.04-0.57; hazard ratio [HR] 0.605, 95% CI 0.42-0.82), and an equal effectiveness between AQ + SP and AQ (PO, odds ratio [OR] 1.70, 95% confidence interval [CI] 0.25-11.44; hazard ratio [HR] 1.40, 95% CI 0.88-2.18). The body temperature was significantly related to the responses. The patient weights were marginally associated to the clinical response.

Conclusion

The proposed analyses, based on usual statistical packages, appeared adapted to take into account the full information contained in the four categorical outcome in malaria trials, as defined by WHO, with the possibility of adjusting on individual and global covariates.

Botulinum toxin A as an adjunct to treatment in the management of the upper limb in children with spastic cerebral palsy (UPDATE)

BACKGROUND

Cerebral palsy (CP) is "a group of permanent disorders of the development of movement and posture causing activity limitation(s) that are attributed to non-progressive disturbance that occurred in the developing fetal or infant brain" (Rosenbaum 2007, p.9). The spastic motor type is the most common form of CP. Therapeutic management may include splinting/casting, passive stretching, facilitation of posture/movement, spasticity-reducing medication and surgery. Botulinum toxin-A (BoNT-A) is now used as an adjunct to these techniques in an attempt to reduce spasticity, improve range of movement and function.

OBJECTIVES

To assess the effectiveness of injections of BoNT-A or BoNT-A and occupational therapy in the treatment of the upper limb in children with CP.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register/CENTRAL (The Cochrane Library, Issue 3, 2008), MEDLINE (1966 to August Week 1 2008), EMBASE (1980 to 2008 Week 28) and CINAHL (1982 to August Week 1 2008).

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing BoNT-A injection or BoNT-A injection and occupational therapy in the upper limb(s) with other types of treatment (including no treatment or placebo) in children with CP.

DATA COLLECTION AND ANALYSIS

Two authors using standardised forms extracted the data independently. Each trial was assessed for internal validity and rated for quality using the PEDro scale. Data were extracted and entered into RevMan 5.0.15.

MAIN RESULTS

Ten trials met the inclusion criteria. PEDro quality ratings ranged from 6/10 to 10/10. Concentration of BoNT-A ranged from 50U/1.0ml to 200U/1.0ml saline with doses of 0.5U to 16U/kg body weight and total doses of 220 to 410 Units (Botox(R)).A combination of BoNT-A and occupational therapy is more effective than occupational therapy alone in reducing impairment, improving activity level outcomes and goal achievement, but not for improving quality of life or perceived self-competence. When compared with placebo or no treatment, there is moderate evidence that BoNT-A alone is not effective.

AUTHORS' CONCLUSIONS

This systematic review found high level evidence supporting the use of BoNT-A as an adjunct to managing the upper limb in children with spastic CP. BoNT-A should not be used in isolation but should be accompanied by planned occupational therapy.Further research is essential to identify children most likely to respond to BoNT-A injections, monitor longitudinal outcomes, determine timing and effect of repeated injections and the most effective dosage, dilution and volume schedules. The most effective adjunct therapies including frequency and intensity of delivery also requires investigation.

Parent training interventions for attention deficit hyperactivity disorder

This is the protocol for a review and there is no abstract. The objectives are as follows: To determine whether parent-training interventions are effective in reducing ADHD symptoms and associated problems (e.g. disruptive behaviour disorders or child-specific impairments such as learning difficulties) in children and young people aged 5-18 with ADHD, compared to controls with no parent-training interventions.

Recent developments in meta-analysis

The art and science of meta-analysis, the combination of results from multiple independent studies, is now more than a century old. In the last 30 years, however, as the need for medical research and clinical practice to be based on the totality of relevant and sound evidence has been increasingly recognized, the impact of meta-analysis has grown enormously. In this paper, we review highlights of recent developments in meta-analysis in medical research. We outline in particular how emphasis has been placed on (i) heterogeneity and random-effects analyses; (ii) special consideration in different areas of application; (iii) assessing bias within and across studies; and (iv) extension of ideas to complex evidence synthesis. We conclude the paper with some remarks on ongoing challenges and possible directions for the future.

Synthesizing medical evidence: systematic reviews and metaanalyses

Systematic reviews and metaanalyses have become increasingly popular ways of summarizing, and sometimes extending, existing medical knowledge. In this review the authors summarize current methods of performing meta-analyses, including the following: formulating a research question; performing a structured literature search and a search for trials not published in the formal medical literature; summarizing and, where appropriate, combining results from several trials; and reporting and presenting results. Topics such as cumulative and Bayesian metaanalysis and metaregression are also addressed. References to textbooks, articles, and Internet resources are also provided. The goal is to assist readers who wish to perform their own metaanalysis or to interpret critically a published example.

A latent normal distribution model for analysing ordinal responses with applications in meta-analysis

We consider the comparison of two treatments (or a treatment and a control/placebo) with responses that are classified into ordinal categories. By operating on the assumption that the responses are manifestations of some underlying continuous variables and that the definitions of the categories for the treatment group and the placebo group are the same in the same clinical test centre, we develop a model to examine the possible treatment effects. These treatment effects can be identified as location effect or dispersion effect. The method can be generalized to analyse clinical test results coming from different centres, where each centre may have its own standard in classifying responses. The method is technically undemanding and can be implemented in a very simple and straightforward way by using easily accessible software that can be downloaded at no cost. Real data sets are analysed for illustration.

Lecithin for dementia and cognitive impairment

BACKGROUND

Alzheimer's disease sufferers have been found to have a lack of the enzyme responsible for converting choline into acetylcholine within the brain. Lecithin is a major dietary source of choline, so extra consumption may reduce the progression of dementia.

OBJECTIVES

To determine the efficacy of lecithin in the treatment of dementia or cognitive impairment.

SEARCH STRATEGY

The Cochrane Dementia and Cognitive Improvement Group's Specialized Register was searched on 15 May 2002 using the terms lecithin and phosphaditylcholine. This contains records from all major databases and many trials databases. Reference lists and relevant books have been examined.

SELECTION CRITERIA

All unconfounded, randomized trials comparing lecithin with placebo in a treatment period longer than one day, in patients with dementia of the Alzheimer type, vascular dementia, mixed vascular and Alzheimer's disease, unclassified or other dementia or unclassified cognitive impairment not fulfilling the criteria for dementia are eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers and cross-checked. Meta-analyses were performed when more than one trial provided data on a comparable outcome on sufficiently similar patients. Random effects analyses were performed whenever heterogeneity between results appeared to be present. Standardised differences in mean outcome measures were used due do the use of different scales and periods of treatment. Odds ratios for dichotomous data were pooled using the Mantel-Haenszel or DerSimonian and Laird methods.

MAIN RESULTS

Twelve randomized trials have been identified involving patients with Alzheimer's disease (265 patients), Parkinsonian dementia (21 patients) and subjective memory problems (90 patients). No trials reported any clear clinical benefit of lecithin for Alzheimer's disease or Parkinsonian dementia. Few trials contributed data to meta-analyses. The only statistically significant result was in favour of placebo for adverse events, based on one trial, which appears likely to be a spurious result. A dramatic result in favour of lecithin was obtained in a trial of subjects with subjective memory problems.

REVIEWER'S CONCLUSIONS

Evidence from randomized trials does not support the use of lecithin in the treatment of patients with dementia. A moderate effect cannot be ruled out, but results from the small trials to date do not indicate priority for a large randomized trial.

Meta-analysis of ordinal outcomes using individual patient data

Meta-analyses are being undertaken in an increasing diversity of diseases and conditions, some of which involve outcomes measured on an ordered categorical scale. We consider methodology for undertaking a meta-analysis on individual patient data for an ordinal response. The approach is based on the proportional odds model, in which the treatment effect is represented by the log-odds ratio. A general framework is proposed for fixed and random effect models. Tests of the validity of the various assumptions made in the meta-analysis models, such as a global test of the assumption of proportional odds between treatments, are presented. The combination of studies with different definitions or numbers of response categories is discussed. The methods are illustrated on two data sets, in a classical framework using SAS and MLn and in a Bayesian framework using BUGS. The relative merits of the three software packages for such meta-analyses are discussed.

An illustrated guide to the methods of meta-analysis

Meta-analysis is now accepted as a necessary tool for the evaluation of health care. Such analyses have been carried out in virtually every area of medicine to evaluate a wide spectrum of health care interventions and policies. This paper has three broad aims: (1) to describe the basic principles of meta-analysis, using a meta-analysis of interventions intended to reduce hospital re-admission rates for illustration; (2) to consider threats to the internal validity of meta-analysis, and the measures which can be taken to minimize their impact; and (3) to present an overview of more specialist and developing methods for synthesizing data, with the intention of outlining the directions meta-analysis may take in the future. The methods used to synthesize studies, which take 'weighted averages' of effect sizes have been refined to a high degree, while the methods for dealing with threats to the validity of meta-analyses such as publication bias, and variations in quality of the primary studies, are at a less advanced stage. However, many consider this standard 'weighted average' approach to meta-analysis not to be 'state of the art' in at least some situations, where the use of more sophisticated methods, generally to explain variation in estimates from different studies and synthesize a broader base of evidence, would be advantageous. Currently, approaches which attempt to do this are mainly still in the experimental stage and, unfortunately, ideas which sound natural and appealing are often difficult to implement in practice. Clearly, it will be some time before they are used routinely, but significant steps have been made.

Oral oestrogen replacement therapy versus placebo for hot flushes

BACKGROUND

Hot flushes and night sweats are common symptoms experienced by menopausal women. Hormone replacement therapy (HRT), containing oestrogens alone or oestrogens together with progestogens in a cyclic or continuous regimen, is often recommended for their alleviation.

OBJECTIVES

To examine the effect of oral HRT compared to placebo on these vasomotor symptoms and the risk of early onset side-effects.

SEARCH STRATEGY

As developed by the Menstrual Disorders Group and Subfertility group of the Cochrane Collaboration.

SELECTION CRITERIA

Double-blind, randomised, placebo-controlled trials of oral HRT therapy for at least three months duration.

DATA COLLECTION AND ANALYSIS

Study quality and outcome data were assessed independently. Random effects models were considered appropriate due to the variety of trial methodologies. The meta-analyses were explored for sensitivity to trial quality and therapy duration. Symptom frequency and severity were assessed separately, together with withdrawals and side-effects. Frequency data were analysed using the Weighted Mean Difference (WMD) between treatment and placebo outcomes. For severity data, odds ratios were estimated from the proportional odds model. From 99 references originally identified, 21 trials meeting the selection criteria were included in the review. Study participants totalled 2,511. Trial duration ranged from three months to three years.

MAIN RESULTS

There was a significant reduction in the weekly hot flush frequency for HRT compared to placebo (WMD -17.46, 95% CI -24.72, -10.21). This was equivalent to a 77% reduction in frequency (95% CI 58.2, 87.5) for HRT relative to placebo. Symptom severity was also significantly reduced compared to placebo (OR 0.13, 95% CI 0.08, 0.22). Withdrawal for lack of efficacy occurred significantly more often on placebo therapy (OR 17.25, 95% CI 8.23, 36.15). Withdrawal for adverse events, commonly breast tenderness, oedema, joint pain and psychological symptoms, was not significantly increased for HRT therapy (OR 1.38, 95% CI 0.87, 2.21). In women who were randomised to placebo treatment, a 50.8% (95% CI 41.7, 58.5) reduction in hot flushes was observed between baseline and end of study.

REVIEWER'S CONCLUSIONS

Oral HRT is highly effective in alleviating hot flushes and night sweats. Therapies purported to reduce such symptoms must be assessed in blinded trials against a placebo or a validated therapy. Withdrawals due to side-effects were only marginally increased in the HRT groups despite the inability to tailor HRT in these fixed dose trials. Comparisons of hormonal doses, product types or regimens require analysis of trials with these specific "within study" comparisons.

The generalization of the odds ratio, risk ratio and risk difference to r x k tables

Familiar measures of association for 2 x 2 tables are the odds ratio, the risk ratio and the risk difference. Analagous measures of outcome-exposure association are desirable when there are several degrees of severity of both exposure and disease outcome. One such measure (alpha), which we label the general odds ratio (OR(G)), was proposed by Agresti. Convenient methods are given for calculation of both standard error and 95 per cent confidence intervals for OR(G). Other approaches to generalizing the odds ratio entail fitting statistical models which might not fit the data, and cannot handle some zero frequencies. We propose a generalization of the risk ratio (RR(G)) following the statistical approaches of Agresti, Goodman and Kruskal. A method of calculating the standard error and 95 per cent confidence interval for RR(G) is provided. A known statistic, Somers' d, fulfils the characteristics necessary for a generalized risk difference (RD(G)). These measures have straightforward interpretations, are easily computed, are at least as precise as other methods and do not require fitting statistical models to the data. We also examine the pooling of such measures as in, for example, meta-analysis.

Anti-spasticity agents for multiple sclerosis

BACKGROUND

Spasticity is a common problem in MS patients causing pain, spasms, loss of function and difficulties in nursing care. A variety of oral and parenteral medications are available.

OBJECTIVES

To assess the absolute and comparative efficacy and tolerability of anti-spasticity agents in multiple sclerosis (MS) patients.

SEARCH STRATEGY

Randomised controlled trials (RCTs) of anti-spasticity agents were identified using MEDLINE, EMBASE, bibliographies of relevant articles, personal communication, manual searches of relevant journals and information from drug companies.

SELECTION CRITERIA

Double-blind, randomised controlled trials (either placebo-controlled or comparative studies) of at least seven days duration.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted data and the findings of the trials were summarised. Missing data were collected by correspondence with principal investigators. A meta-analysis was not performed due to the inadequacy of outcome measures and methodological problems with the studies reviewed.

MAIN RESULTS

Twenty-three placebo-controlled studies (using baclofen, dantrolene, tizanidine, botulinum toxin, vigabatrin, prazepam and threonine) and thirteen comparative studies met the selection criteria. Only thirteen of these studies used the Ashworth scale, of which only three of the six placebo-controlled trials and none of the seven comparative studies showed a statistically significant difference between test drugs. Spasms, other symptoms and overall impressions were only assessed using unvalidated scores and results of functional assessments were inconclusive.

REVIEWER'S CONCLUSIONS

The absolute and comparative efficacy and tolerability of anti-spasticity agents in multiple sclerosis is poorly documented and no recommendations can be made to guide prescribing. The rationale for treating features of the upper motor neurone syndrome must be better understood and sensitive, validated spasticity measures need to be developed.

Does acute normovolemic hemodilution reduce perioperative allogeneic transfusion? A meta-analysis. The International Study of Perioperative Transfusion

The objective of this study was to systematically review the literature and to statistically summarize the evidence evaluating acute normovolemic hemodilution (ANH). Prospective, randomized, controlled trials of ANH that reported either the proportion of patients exposed to allogeneic blood or the units of allogeneic blood transfused were included. All types and languages of publication were eligible. Of 1573 identified publications, 24 trials (containing a total of 1218 patients) were included in the meta-analysis. When all trials were pooled, ANH reduced the likelihood of exposure to allogeneic blood (odds ratio [OR] 0.31, 95% confidence interval [CI] 0.15, 0.62) and the total units of allogeneic blood transfused (weighted mean difference [WMD] -2.22 U, 95% CI -3.57, -0.86). However, there was marked heterogeneity of the results. In trials using a protocol to guide perioperative transfusion, ANH failed to reduce either the likelihood of transfusion (OR 0.64, 95% CI 0.31, 1.31) or the units administered (WMD -0.25 U, 95% CI -0.60, 0.10). Adverse events were incompletely reported. It is possible that biased experimental design is, in part, responsible for the reported efficacy of this technique.

IMPLICATIONS

after a systematic literature review, 24 randomized trials examining the role of acute normovolemic hemodilution were identified, pooled, and summarized using statistical techniques. Many studies reported an impressive reduction in blood transfused. Closer examination suggests that these reductions in blood exposure may be due to flawed study design.

Does acute normovolemic hemodilution reduce perioperative allogeneic transfusion? A meta-analysis. The International Study of Perioperative Transfusion

The objective of this study was to systematically review the literature and to statistically summarize the evidence evaluating acute normovolemic hemodilution (ANH). Prospective, randomized, controlled trials of ANH that reported either the proportion of patients exposed to allogeneic blood or the units of allogeneic blood transfused were included. All types and languages of publication were eligible. Of 1573 identified publications, 24 trials (containing a total of 1218 patients) were included in the meta-analysis. When all trials were pooled, ANH reduced the likelihood of exposure to allogeneic blood (odds ratio [OR] 0.31, 95% confidence interval [CI] 0.15, 0.62) and the total units of allogeneic blood transfused (weighted mean difference [WMD] -2.22 U, 95% CI -3.57, -0.86). However, there was marked heterogeneity of the results. In trials using a protocol to guide perioperative transfusion, ANH failed to reduce either the likelihood of transfusion (OR 0.64, 95% CI 0.31, 1.31) or the units administered (WMD -0.25 U, 95% CI -0.60, 0.10). Adverse events were incompletely reported. It is possible that biased experimental design is, in part, responsible for the reported efficacy of this technique.

IMPLICATIONS

after a systematic literature review, 24 randomized trials examining the role of acute normovolemic hemodilution were identified, pooled, and summarized using statistical techniques. Many studies reported an impressive reduction in blood transfused. Closer examination suggests that these reductions in blood exposure may be due to flawed study design.

Meta-analysis and prospective meta-analysis in childhood leukemia clinical research

In this paper, we consider the role of meta-analysis and 'prospective meta-analysis' studies in childhood acute lymphocytic leukemia (ALL). In this issue, Valsecchi and Masera [1] give a thoughtful discourse, generally favorable to this approach. This article presents the opposite point of view. The aims of our article are to present the implications in clinical, rather than biostatistical terms, and to provide an extensive literature review of the subject of meta-analysis. We conclude that treatment assessments, resulting from meta-analysis of closed studies (retrospective) should be met with healthy skepticism. Trials requiring international resources should be true intergroup trials with a single coordinating center, rather than prospective meta-analysis, unless it is a question grafted onto each group's own research agenda. For example, each group might ask its own systemic control question, but a CNS protection question is asked collectively.