Lessons for cluster randomized trials in the twenty-first century: a systematic review of trials in primary care

Statistical analysis and handling of missing data in cluster randomised trials: protocol for a systematic review

INTRODUCTION

Cluster randomised trials (CRTs) randomise participants in groups, rather than as individuals, and are key tools used to assess interventions in health research where treatment contamination is likely or if individual randomisation is not feasible. Missing outcome data can reduce power in trials, including in CRTs, and is a potential source of bias. The current review focuses on evaluating methods used in statistical analysis and handling of missing data with respect to the primary outcome in CRTs.

METHODS AND ANALYSIS

We will search for CRTs published between August 2013 and July 2014 using PubMed, Web of Science and PsycINFO. We will identify relevant studies by screening titles and abstracts, and examining full-text articles based on our predefined study inclusion criteria. 86 studies will be randomly chosen to be included in our review. Two independent reviewers will collect data from each study using a standardised, prepiloted data extraction template. Our findings will be summarised and presented using descriptive statistics.

ETHICS AND DISSEMINATION

This methodological systematic review does not need ethical approval because there are no data used in our study that are linked to individual patient data. After completion of this systematic review, data will be immediately analysed, and findings will be disseminated through a peer-reviewed publication and conference presentation.

OARSI Clinical Trials Recommendations: Design and conduct of implementation trials of interventions for osteoarthritis

Rigorous implementation research is important for testing strategies to improve the delivery of effective osteoarthritis (OA) interventions. The objective of this manuscript is to describe principles of implementation research, including conceptual frameworks, study designs and methodology, with specific recommendations for randomized clinical trials of OA treatment and management. This manuscript includes a comprehensive review of prior research and recommendations for implementation trials. The review of literature included identification of seminal articles on implementation research methods, as well as examples of previous exemplar studies using these methods. In addition to a comprehensive summary of this literature, this manuscript provides key recommendations for OA implementation trials. This review concluded that to date there have been relatively few implementation trials of OA interventions, but this is an emerging area of research. Future OA clinical trials should routinely consider incorporation of implementation aims to enhance translation of findings.

The effect of heterogeneous variance on efficiency and power of cluster randomized trials with a balanced 2 × 2 factorial design

Sample size calculation for cluster randomized trials (CRTs) with a [Formula: see text] factorial design is complicated due to the combination of nesting (of individuals within clusters) with crossing (of two treatments). Typically, clusters and individuals are allocated across treatment conditions in a balanced fashion, which is optimal under homogeneity of variance. However, the variance is likely to be heterogeneous if there is a treatment effect. An unbalanced allocation is then more efficient, but impractical because the optimal allocation depends on the unknown variances. Focusing on CRTs with a [Formula: see text] design, this paper addresses two questions: How much efficiency is lost by having a balanced design when the outcome variance is heterogeneous? How large must the sample size be for a balanced allocation to have sufficient power under heterogeneity of variance? We consider different scenarios of heterogeneous variance. Within each scenario, we determine the relative efficiency of a balanced design, as a function of the level (cluster, individual, both) and amount of heterogeneity of the variance. We then provide a simple correction of the sample size for the loss of power due to heterogeneity of variance when a balanced allocation is used. The theory is illustrated with an example of a published 2 x2 CRT.

Intracluster correlation coefficients for sample size calculations related to cardiovascular disease prevention and management in primary care practices

BACKGROUND

Few studies have comprehensively reported intracluster correlation coefficient (ICC) estimates for outcomes collected in primary care settings. Using data from a large primary care study, we aimed to: a) report ICCs for process-of-care and clinical outcome measures related to cardiovascular disease management and prevention, and b) investigate the impact of practice structure and rurality on ICC estimates.

METHODS

We used baseline data from the Improved Delivery of Cardiovascular Care (IDOCC) trial to estimate ICC values. Data on 5,140 patients from 84 primary care practices across Eastern Ontario, Canada were collected through chart abstraction. ICC estimates were calculated using an ANOVA approach and were calculated for all patients and separately for patient subgroups defined by condition (i.e., coronary artery disease, diabetes, chronic kidney disease, hypertension, dyslipidemia, and smoking). We compared ICC estimates between practices in which data were collected from a single physician versus those that had multiple participating physicians and between urban versus rural practices.

RESULTS

ICC estimates ranged from 0 to 0.173, with a median of 0.056. The median ICC estimate for dichotomous process outcomes (0.088) was higher than that for continuous clinical outcomes (0.035). ICC estimates calculated for single physician practices were higher than those for practices with multiple physicians for both process (average 3.9-times higher) and clinical measures (average 1.9-times higher). Urban practices tended to have higher process-of-care ICC estimates than rural practices, particularly for measuring lipid profiles and estimated glomerular filtration rates.

CONCLUSION

To our knowledge, this is the most comprehensive summary of cardiovascular-related ICCs to be reported from Canadian primary care practices. Differences in ICC estimates based on practice structure and location highlight the importance of understanding the context in which external ICC estimates were determined prior to their use in sample size calculations. Failure to choose appropriate ICC estimates can have substantial implications for the design of a cluster randomized trial.

Challenges of cluster randomized trials

Cluster randomized trials are trials that randomize clusters of people, rather than individuals. They are becoming increasingly common. A number of innovations have been developed recently, particularly in the calculation of the required size of a cluster trial, the handling of missing data, designs to minimize recruitment bias, the ethics of cluster randomized trials and the stepped wedge design. This article will highlight and illustrate these developments. It will also discuss issues with regards to the reporting of cluster randomized trials.

Effect of a multifaceted educational program for care staff concerning fecal incontinence in nursing home patients: study protocol of a cluster randomized controlled trial

Background

Fecal incontinence has a high prevalence in the older population, which cannot be explained by comorbidity or the anatomical or psychological changes of aging alone. Fecal incontinence leads to a high economic burden to the healthcare system and is an important cause of institutionalization. In addition, fecal incontinence is associated with shame, social isolation and reduced quality of life. The importance of identifying treatable causes in the frail elderly is strongly emphasized. It is recommended that an assessment of fecal incontinence should be implemented as part of an evaluation of older patients. Although there is a substantial evidence base to guide choice of implementation activities targeting healthcare professionals, little implementation research has focused on the care of older people nor involved care processes or care personnel. This study is based on the assumption that fecal incontinence among nursing home patients can be prevented, cured or ameliorated by offering care staff knowledge of best practice through a multifaceted educational program. The primary objective is to test the hypothesis that a multifaceted educational program for nursing home care staff on assessment and treatment of fecal incontinence reduces patients’ frequency of fecal incontinence.

Methods/design

The study is a two-armed, parallel cluster-randomized controlled trial. Primary outcome is the frequency of fecal incontinence among patients. Sample size calculations resulted in a need for a total sample of 240 patients. Twenty nursing home units in one city in Norway will be recruited and allocated to intervention or control by an independent statistician using computer-generated tables. The intervention is a multifaceted educational program. Units in the control arm will provide care as usual. The intervention period is 3 months. Data will be collected at baseline, 3, and 6 months. Data will be analyzed using mixed effect models with the cluster treated as a random effect.

Discussion

This study is the first randomized controlled trial specifically focusing on this neglected area. The result of the study will give evidence for best practice for continence care in nursing homes, and organizational advice concerning implementation strategies.

Trial registration

ClinicalTrials.gov: NCT02183740, registered June 2014.

Design of an international multicentre RCT on group schema therapy for borderline personality disorder

BACKGROUND

Borderline personality disorder (BPD) is a severe and highly prevalent mental disorder. Schema therapy (ST) has been found effective in the treatment of BPD and is commonly delivered through an individual format. A group format (group schema therapy, GST) has also been developed. GST has been found to speed up and amplify the treatment effects found for individual ST. Delivery in a group format may lead to improved cost-effectiveness. An important question is how GST compares to treatment as usual (TAU) and what format for delivery of schema therapy (format A; intensive group therapy only, or format B; a combination of group and individual therapy) produces the best outcomes.

METHODS/DESIGN

An international, multicentre randomized controlled trial (RCT) will be conducted with a minimum of fourteen participating centres. Each centre will recruit multiple cohorts of at least sixteen patients. GST formats as well as the orders in which they are delivered to successive cohorts will be balanced. Within countries that contribute an uneven number of sites, the orders of GST formats will be balanced within a difference of one. The RCT is designed to include a minimum of 448 patients with BPD. The primary clinical outcome measure will be BPD severity. Secondary clinical outcome measures will include measures of BPD and general psychiatric symptoms, schemas and schema modes, social functioning and quality of life. Furthermore, an economic evaluation that consists of cost-effectiveness and cost-utility analyses will be performed using a societal perspective. Lastly, additional investigations will be carried out that include an assessment of the integrity of GST, a qualitative study on patients' and therapists' experiences with GST, and studies on variables that might influence the effectiveness of GST.

DISCUSSION

This trial will compare GST to TAU for patients with BPD as well as two different formats for the delivery of GST. By combining an evaluation of clinical effectiveness, an economic evaluation and additional investigations, it will contribute to an evidence-based understanding of which treatment should be offered to patients with BPD from clinical, economic, and stakeholders' perspectives.

TRIAL REGISTRATION

Netherlands Trial Register NTR2392. Registered 25 June 2010.

Small sample performance of bias-corrected sandwich estimators for cluster-randomized trials with binary outcomes

The sandwich estimator in generalized estimating equations (GEE) approach underestimates the true variance in small samples and consequently results in inflated type I error rates in hypothesis testing. This fact limits the application of the GEE in cluster-randomized trials (CRTs) with few clusters. Under various CRT scenarios with correlated binary outcomes, we evaluate the small sample properties of the GEE Wald tests using bias-corrected sandwich estimators. Our results suggest that the GEE Wald z-test should be avoided in the analyses of CRTs with few clusters even when bias-corrected sandwich estimators are used. With t-distribution approximation, the Kauermann and Carroll (KC)-correction can keep the test size to nominal levels even when the number of clusters is as low as 10 and is robust to the moderate variation of the cluster sizes. However, in cases with large variations in cluster sizes, the Fay and Graubard (FG)-correction should be used instead. Furthermore, we derive a formula to calculate the power and minimum total number of clusters one needs using the t-test and KC-correction for the CRTs with binary outcomes. The power levels as predicted by the proposed formula agree well with the empirical powers from the simulations. The proposed methods are illustrated using real CRT data. We conclude that with appropriate control of type I error rates under small sample sizes, we recommend the use of GEE approach in CRTs with binary outcomes because of fewer assumptions and robustness to the misspecification of the covariance structure.

Home-use icterometry in neonatal hyperbilirubinaemia: Cluster-randomised controlled trial in Vietnam

AIM

To determine whether home-use icterometry improves parental recognition of neonatal jaundice, early care seeking and treatment to minimize risks of bilirubin encephalopathy.

METHODS

Cluster-randomised controlled trial of community-level icterometry used at home by mothers in Chi Linh, Vietnam. Rural health-care workers identified and enrolled term newborns. Post-partum mothers received jaundice education and icterometry instructions and were cluster-randomised by commune. Cases received icterometers (icterometer group (IG)) and controls did not (control group (CG)). Subjects received mobile telephone calls from post-natal days 2-7 to determine maternal recognition by visual inspection and icterometer detection of jaundice (≥ 3.0 on five-point scale). Mothers without telephones, premature newborns (<35 weeks) or newborns hospitalised >5 days were excluded.

RESULTS

Three hundred fifty-two subjects were enrolled (183 IG and 169 CG), of whom 11 (3.4%) were lost to telephone follow-up. Jaundice was recognised and/or detected in 94 (27%) of all newborns. Icterometry helped 11 mothers (6%) detect neonatal jaundice that was not visually recognised by IG mothers. Detection by IG mothers was not statistically greater than CG mothers (P = 0.09). Follow-up care seeking was 8% in both groups (P = 0.2), and 11% of jaundiced newborns received treatment (9% IG vs. 16% CG, P = 0.3). Newborns who received care had bilirubin measurements that averaged 257 μmol/L IG vs. 322 μmol/L CG (P = 0.3). There were no deaths.

CONCLUSIONS

In this pilot study, home-use icterometry may help improve parental detection of jaundice in rural Vietnam. However, larger studies are necessary to determine the changes in recognition, care seeking and treatment.

Effectiveness of the Assessment of Burden of Chronic Obstructive Pulmonary Disease (ABC) tool: study protocol of a cluster randomised trial in primary and secondary care

Background

Chronic Obstructive Pulmonary Disease (COPD) is a growing worldwide problem that imposes a great burden on the daily life of patients. Since there is no cure, the goal of treating COPD is to maintain or improve quality of life. We have developed a new tool, the Assessment of Burden of COPD (ABC) tool, to assess and visualize the integrated health status of patients with COPD, and to provide patients and healthcare providers with a treatment algorithm. This tool may be used during consultations to monitor the burden of COPD and to adjust treatment if necessary. The aim of the current study is to analyse the effectiveness of the ABC tool compared with usual care on health related quality of life among COPD patients over a period of 18 months.

Methods/Design

A cluster randomised controlled trial will be conducted in COPD patients in both primary and secondary care throughout the Netherlands. An intervention group, receiving care based on the ABC tool, will be compared with a control group receiving usual care. The primary outcome will be the change in score on a disease-specific-quality-of-life questionnaire, the Saint George Respiratory Questionnaire. Secondary outcomes will be a different questionnaire (the COPD Assessment Test), lung function and number of exacerbations. During the 18 months follow-up, seven measurements will be conducted, including a baseline and final measurement. Patients will receive questionnaires to be completed at home. Additional data, such as number of exacerbations, will be recorded by the patients’ healthcare providers. A total of 360 patients will be recruited by 40 general practitioners and 20 pulmonologists. Additionally, a process evaluation will be performed among patients and healthcare providers.

Discussion

The new ABC tool complies with the 2014 Global Initiative for Chronic Obstructive Lung Disease guidelines, which describe the necessity to classify patients on both their airway obstruction and a comprehensive symptom assessment. It has been developed to classify patients, but also to provide visual insight into the burden of COPD and to provide treatment advice.

Trial registration

Netherlands Trial Register, NTR3788.

Are missing data adequately handled in cluster randomised trials? A systematic review and guidelines

BACKGROUND

Missing data are a potential source of bias, and their handling in the statistical analysis can have an important impact on both the likelihood and degree of such bias. Inadequate handling of the missing data may also result in invalid variance estimation. The handling of missing values is more complex in cluster randomised trials, but there are no reviews of practice in this field.

OBJECTIVES

A systematic review of published trials was conducted to examine how missing data are reported and handled in cluster randomised trials.

METHODS

We systematically identified cluster randomised trials, published in English in 2011, using the National Library of Medicine (MEDLINE) via PubMed. Non-randomised and pilot/feasibility trials were excluded, as were reports of secondary analyses, interim analyses, and economic evaluations and those where no data were at the individual level. We extracted information on missing data and the statistical methods used to deal with them from a random sample of the identified studies.

RESULTS

We included 132 trials. There was evidence of missing data in 95 (72%). Only 32 trials reported handling missing data, 22 of them using a variety of single imputation techniques, 8 using multiple imputation without accommodating the clustering and 2 stating that their likelihood-based complete case analysis accounted for missing values because the data were assumed Missing-at-Random.

LIMITATIONS

The results presented in this study are based on a large random sample of cluster randomised trials published in 2011, identified in electronic searches and therefore possibly missing some trials, most likely of poorer quality. Also, our results are based on information in the main publication for each trial. These reports may omit some important information on the presence of, and reasons for, missing data and on the statistical methods used to handle them. Our extraction methods, based on published reports, could not distinguish between missing data in outcomes and missing data in covariates. This distinction may be important in determining the assumptions about the missing data mechanism necessary for complete case analyses to be valid.

CONCLUSIONS

Missing data are present in the majority of cluster randomised trials. However, they are poorly reported, and most authors give little consideration to the assumptions under which their analysis will be valid. The majority of the methods currently used are valid under very strong assumptions about the missing data, whose plausibility is rarely discussed in the corresponding reports. This may have important consequences for the validity of inferences in some trials. Methods which result in valid inferences under general Missing-at-Random assumptions are available and should be made more accessible.

Changing cluster composition in cluster randomised controlled trials: design and analysis considerations

BACKGROUND

There are many methodological challenges in the conduct and analysis of cluster randomised controlled trials, but one that has received little attention is that of post-randomisation changes to cluster composition. To illustrate this, we focus on the issue of cluster merging, considering the impact on the design, analysis and interpretation of trial outcomes.

METHODS

We explored the effects of merging clusters on study power using standard methods of power calculation. We assessed the potential impacts on study findings of both homogeneous cluster merges (involving clusters randomised to the same arm of a trial) and heterogeneous merges (involving clusters randomised to different arms of a trial) by simulation. To determine the impact on bias and precision of treatment effect estimates, we applied standard methods of analysis to different populations under analysis.

RESULTS

Cluster merging produced a systematic reduction in study power. This effect depended on the number of merges and was most pronounced when variability in cluster size was at its greatest. Simulations demonstrate that the impact on analysis was minimal when cluster merges were homogeneous, with impact on study power being balanced by a change in observed intracluster correlation coefficient (ICC). We found a decrease in study power when cluster merges were heterogeneous, and the estimate of treatment effect was attenuated.

CONCLUSIONS

Examples of cluster merges found in previously published reports of cluster randomised trials were typically homogeneous rather than heterogeneous. Simulations demonstrated that trial findings in such cases would be unbiased. However, simulations also showed that any heterogeneous cluster merges would introduce bias that would be hard to quantify, as well as having negative impacts on the precision of estimates obtained. Further methodological development is warranted to better determine how to analyse such trials appropriately. Interim recommendations include avoidance of cluster merges where possible, discontinuation of clusters following heterogeneous merges, allowance for potential loss of clusters and additional variability in cluster size in the original sample size calculation, and use of appropriate ICC estimates that reflect cluster size.

Effectiveness and cost-effectiveness of a group-based pain self-management intervention for patients undergoing total hip replacement: feasibility study for a randomized controlled trial

Background

Total hip replacement (THR) is a common elective surgical procedure and can be effective for reducing chronic pain. However, waiting times can be considerable. A pain self-management intervention may provide patients with skills to more effectively manage their pain and its impact during their wait for surgery. This study aimed to evaluate the feasibility of conducting a randomized controlled trial to assess the effectiveness and cost-effectiveness of a group-based pain self-management course for patients undergoing THR.

Methods

Patients listed for a THR at one orthopedic center were posted a study invitation pack. Participants were randomized to attend a pain self-management course plus standard care or standard care only. The lay-led course was delivered by Arthritis Care and consisted of two half-day sessions prior to surgery and one full-day session after surgery. Participants provided outcome and resource-use data using a diary and postal questionnaires prior to surgery and one month, three months and six months after surgery. Brief telephone interviews were conducted with non-participants to explore barriers to participation.

Results

Invitations were sent to 385 eligible patients and 88 patients (23%) consented to participate. Interviews with 57 non-participants revealed the most common reasons for non-participation were views about the course and transport difficulties. Of the 43 patients randomized to the intervention group, 28 attended the pre-operative pain self-management sessions and 11 attended the post-operative sessions. Participant satisfaction with the course was high, and feedback highlighted that patients enjoyed the group format. Retention of participants was acceptable (83% of recruited patients completed follow-up) and questionnaire return rates were high (72% to 93%), with the exception of the pre-operative resource-use diary (35% return rate). Resource-use completion rates allowed for an economic evaluation from the health and social care payer perspective.

Conclusions

This study highlights the importance of feasibility work prior to a randomized controlled trial to assess recruitment methods and rates, barriers to participation, logistics of scheduling group-based interventions, acceptability of the intervention and piloting resource use questionnaires to improve data available for economic evaluations. This information is of value to researchers and funders in the design and commissioning of future research.

Trial registration

Current Controlled Trials ISRCTN52305381.

Interventions for preventing the spread of infestation in close contacts of people with scabies

BACKGROUND

Scabies, caused by Sarcoptes scabiei variety hominis or the human itch mite, is a common parasitic infection. While anyone can become infected, it causes significant morbidity in immunocompromised hosts and it spreads easily between human hosts where there is overcrowding or poor sanitation. The most common symptom reported is itch which is worse at night. As the symptoms are attributed to an allergic reaction to the mite, symptoms usually develop between four to six weeks after primary infection. Therefore, people may be infected for some time prior to developing symptoms. During this time, while asymptomatic, they may spread infection to others they are in close contact with. Consequently, it is usually recommended that when an index case is being treated, others who have been in close contact with the index case should also be provided with treatment.

OBJECTIVES

To assess the effects of prophylactic interventions for contacts of people with scabies to prevent infestation in the contacts.

SEARCH METHODS

We searched electronic databases (Cochrane Occupational Safety and Health Review Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (Ovid), Pubmed, EMBASE, LILACS, CINAHL, OpenGrey and WHO ICTRP) up to November 2013.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or cluster RCTs which compared prophylactic interventions which were given to contacts of index cases with scabies infestation. Interventions could be compared to each other, or to placebo or to no treatment. Both drug treatments and non-drug treatments were acceptable.

DATA COLLECTION AND ANALYSIS

Two authors intended to extract dichotomous data (developed infection or did not develop infection) for the effects of interventions and report this as risk ratios with 95% confidence intervals. We intended to report any adverse outcomes similarly.

MAIN RESULTS

We did not include any trials in this review. Out of 29 potentially-relevant studies, we excluded 16 RCTs as the data for the contacts were either not reported or were reported only in combination with the outcomes for the index cases. We excluded a further 11 studies as they were not RCTs. We also excluded one study as not all subjects were examined at baseline and follow-up, and another as it was a case study.

AUTHORS' CONCLUSIONS

The effects of providing prophylactic treatments for contacts of people with scabies to prevent infestation are unknown. We need well-designed RCTs of the use of prophylactic measures to prevent the transmission of scabies conducted with people who had the opportunity for prolonged skin contact with an index case, such as family members, healthcare workers or residential care personnel, within the previous six weeks.

Short structured general mental health in service training programme in Kenya improves patient health and social outcomes but not detection of mental health problems - a pragmatic cluster randomised controlled trial

TRIAL DESIGN

A pragmatic cluster randomised controlled trial.

METHODS

PARTICIPANTS

Clusters were primary health care clinics on the Ministry of Health list. Clients were eligible if they were aged 18 and over.

INTERVENTIONS

Two members of staff from each intervention clinic received the training programme. Clients in both intervention and control clinics subsequently received normal routine care from their health workers.

OBJECTIVE

To examine the impact of a mental health inservice training on routine detection of mental disorder in the clinics and on client outcomes.

OUTCOMES

The primary outcome was the rate of accurate routine clinic detection of mental disorder and the secondary outcome was client recovery over a twelve week follow up period. Randomisation: clinics were randomised to intervention and control groups using a table of random numbers. Blinding: researchers and clients were blind to group assignment.

RESULTS

Numbers randomised: 49 and 50 clinics were assigned to intervention and control groups respectively. 12 GHQ positive clients per clinic were identified for follow up. Numbers analysed: 468 and 478 clients were followed up for three months in intervention and control groups respectively.

OUTCOME

At twelve weeks after training of the intervention group, the rate of accurate routine clinic detection of mental disorder was greater than 0 in 5% versus 0% of the intervention and control groups respectively, in both the intention to treat analysis (p = 0.50) and the per protocol analysis (p =0.50). Standardised effect sizes for client improvement were 0.34 (95% CI = (0.01,0.68)) for the General Health Questionnaire, 0.39 ((95% CI = (0.22, 0.61)) for the EQ and 0.49 (95% CI = (0.11,0.87)) for WHODAS (using ITT analysis); and 0.43 (95% CI = (0.09,0.76)) for the GHQ, 0.44 (95% CI = (0.22,0.65)) for the EQ and 0.58 (95% CI = (0.18,0.97)) for WHODAS (using per protocol analysis).

HARMS

None identified.

CONCLUSION

The training programme did not result in significantly improved recorded diagnostic rates of mental disorders in the routine clinic consultation register, but did have significant effects on patient outcomes in routine clinical practice.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number Register ISRCTN53515024.

A systematic review of cluster randomised trials in residential facilities for older people suggests how to improve quality

BACKGROUND

Previous reviews of cluster randomised trials have been critical of the quality of the trials reviewed, but none has explored determinants of the quality of these trials in a specific field over an extended period of time. Recent work suggests that correct conduct and reporting of these trials may require more than published guidelines. In this review, our aim was to assess the quality of cluster randomised trials conducted in residential facilities for older people, and to determine whether (1) statistician involvement in the trial and (2) strength of journal endorsement of the Consolidated Standards of Reporting Trials (CONSORT) statement influence quality.

METHODS

We systematically identified trials randomising residential facilities for older people, or parts thereof, without language restrictions, up to the end of 2010, using National Library of Medicine (Medline) via PubMed and hand-searching. We based quality assessment criteria largely on the extended CONSORT statement for cluster randomised trials. We assessed statistician involvement based on statistician co-authorship, and strength of journal endorsement of the CONSORT statement from journal websites.

RESULTS

73 trials met our inclusion criteria. Of these, 20 (27%) reported accounting for clustering in sample size calculations and 54 (74%) in the analyses. In 29 trials (40%), methods used to identify/recruit participants were judged by us to have potentially caused bias or reporting was unclear to reach a conclusion. Some elements of quality improved over time but this appeared not to be related to the publication of the extended CONSORT statement for these trials. Trials with statistician/epidemiologist co-authors were more likely to account for clustering in sample size calculations (unadjusted odds ratio 5.4, 95% confidence interval 1.1 to 26.0) and analyses (unadjusted OR 3.2, 1.2 to 8.5). Journal endorsement of the CONSORT statement was not associated with trial quality.

CONCLUSIONS

Despite international attempts to improve methods in cluster randomised trials, important quality limitations remain amongst these trials in residential facilities. Statistician involvement on trial teams may be more effective in promoting quality than further journal endorsement of the CONSORT statement. Funding bodies and journals should promote statistician involvement and co-authorship in addition to adherence to CONSORT guidelines.

Structured diagnostic and treatment approach versus the usual primary care approach in patients with gastroesophageal reflux disease: a cluster-randomized multicenter study

GOALS

To compare the clinical outcomes of gastroesophageal reflux disease (GERD) patients treated with an implemented new structured pathway (NSP) or according to existing local clinical practices [old clinical pathway (OCP)].

BACKGROUND

GERD is a major challenge at the primary care level.

STUDY

Primary care centers (n=24) were cluster randomized to handle patients suffering from symptoms suggestive of GERD according to the NSP (n=97) or the OCP (n=134). In the NSP, the GerdQ questionnaire score was used both for diagnosis and management including treatment. We used validated questionnaires to evaluate disease symptoms, quality of life, and costs at inclusion and at follow-up 2 to 6 months later.

RESULTS

On the basis of the Reflux Disease Questionnaire, 56% of the patients treated with the NSP reported total symptom relief at the follow-up compared with 33% in the OCP group (P=0.0013). The reflux symptoms after treatment affected daily activities to a lesser extent in the patients in the NSP group compared with the OCP group (10% vs. 13%, respectively, P=0.01). The utility score of the EuroQoL-5D questionnaire improved more in the NSP group than in the OCP group (0.05 vs. 0.02, respectively, P<0.001). The patients in the NSP group had an approximately 50% lower average total cost for GERD-related health care resources compared with the OCP group [301 Swedish Kronor (SEK) vs. 588 SEK, respectively, NS].

CONCLUSIONS

The management of GERD patients in primary care centers using a structured clinical pathway and the results of the GerdQ improves the clinical outcome compared with prevailing local routines (NCT00842387).

The reporting quality assessment of complex interventions' articles in traditional chinese medicine

Objective. To realize the current situation and problems of complex interventions' clinical trials. Methods. Searching at Chinese Journal Integrated Traditional and Western Medicine and Journal of Traditional Chinese Medicine from 2007 to 2012 by hand, we identified complex interventions' articles, and then we used the proposed criteria of complex interventions and CONSORT FOR TCM to evaluate. Results. All data is presented as counts with percentages and details in tables. Conclusion. Our evaluation presented that complex interventions have many defects: the selection of the intervention's components lacks rationale, complex interventions were short of fundamental researches, components' interactions were ambiguous, and the advantages of complex interventions were not mentioned. Furthermore, explanation of sample size, blind, quality control, ethical approval, and inform consent were neglected in different degrees.

The impact of intensifying acid suppression on sleep disturbance related to gastro-oesophageal reflux disease in primary care

BACKGROUND

Sleep disturbance is common in patients with GERD but there has been little evaluation of this problem in primary care in patients already taking therapy.

AIM

To evaluate the impact of administering a questionnaire (PASS test) to identify patients with sleep problems and evaluate the efficacy of esomeprazole to improve sleep disturbance in patients with GERD.

METHODS

This was a primary care based cluster-randomised, open-label study where practices were assigned to intervention or control groups. PASS test failures continued current therapy (control) or were switched to 4 weeks' once-daily esomeprazole 20 or 40 mg (intervention). Patients were evaluated at the end of 4 weeks and the outcomes that were assessed were the sleep questions from the Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire and the presence or absence of sleep disturbance from the PASS test questionnaire.

RESULTS

A total of 1388 patients with evaluable data at 4 weeks were included in the analysis and 825 reported GERD-related sleep disturbance at baseline. At 4 weeks, 161 of 291 of control patients (55%) reported continued sleep disturbance compared to 120 of 534 (22.5%) of intervention patients [number needed to treat of 3: 95% confidence intervals (CI): 2.5-4]. There was a mean improvement in QOLRAD scores related to sleep in the intervention patients compared to control patients (mean improvement = 4.91; 95% CI: 3.73-6.09).

CONCLUSION

A PASS strategy identifies GERD patients with sleep disturbance in primary care that will benefit from a change in acid-suppressive therapy. ClinicalTrials.gov identifier: NCT00392002; study code: D9612L00096.

Effectiveness of medicines review with web-based pharmaceutical treatment algorithms in reducing potentially inappropriate prescribing in older people in primary care: a cluster randomized trial (OPTI-SCRIPT study protocol)

BACKGROUND

Potentially inappropriate prescribing in older people is common in primary care and can result in increased morbidity, adverse drug events, hospitalizations and mortality. In Ireland, 36% of those aged 70 years or over received at least one potentially inappropriate medication, with an associated expenditure of over €45 million.The main objective of this study is to determine the effectiveness and acceptability of a complex, multifaceted intervention in reducing the level of potentially inappropriate prescribing in primary care.

METHODS/DESIGN

This study is a pragmatic cluster randomized controlled trial, conducted in primary care (OPTI-SCRIPT trial), involving 22 practices (clusters) and 220 patients. Practices will be allocated to intervention or control arms using minimization, with intervention participants receiving a complex multifaceted intervention incorporating academic detailing, medicines review with web-based pharmaceutical treatment algorithms that provide recommended alternative treatment options, and tailored patient information leaflets. Control practices will deliver usual care and receive simple patient-level feedback on potentially inappropriate prescribing. Routinely collected national prescribing data will also be analyzed for nonparticipating practices, acting as a contemporary national control. The primary outcomes are the proportion of participant patients with potentially inappropriate prescribing and the mean number of potentially inappropriate prescriptions per patient. In addition, economic and qualitative evaluations will be conducted.

DISCUSSION

This study will establish the effectiveness of a multifaceted intervention in reducing potentially inappropriate prescribing in older people in Irish primary care that is generalizable to countries with similar prescribing challenges.

TRIAL REGISTRATION

Current controlled trials ISRCTN41694007.

Comparison of population-averaged and cluster-specific models for the analysis of cluster randomized trials with missing binary outcomes: a simulation study

Abstracts

An evaluation of a self-management package for people with diabetes at risk of chronic kidney disease

AIMS AND OBJECTIVES

The overall purpose was to develop, test and evaluate an educational package to help people with diabetes self-manage their risk of developing chronic kidney disease (CKD), one of the main complications of diabetes.

BACKGROUND

Management of people in primary care who have both CKD and diabetes can be controlled by strict blood pressure (BP) and blood sugar control and advice on lifestyle changes, such as smoking cessation. However, there is little evidence to support the assertion that self-management can slow the rate of kidney disease progression.

DESIGN

A mixed-method longitudinal study. Development of the self-management package was informed by the findings of a case study in six GP Practices and also through interviews with 15 patients.

METHODS

Testing of the self-management package was undertaken in the same six Practices, with one additional control Practice. Patients with Type 1 or Type 2 diabetes at risk of kidney disease were included. Outcomes in patients in the participating surgeries who did receive a pack (n = 116) were compared with patients in the control group (n = 60) over 6 time points.

RESULTS

At the end of the study (time point 6), the intervention group had a mean systolic BP of 4.1 mmHg lower and mean diastolic BP of 2.7 mmHg lower than in the control group.

CONCLUSION

Self-management techniques such as understanding of, and subsequent concordance with, prescribed BP medication may contribute to a reduction in BP, which in turn will reduce cardiovascular risk.

RELEVANCE TO CLINICAL PRACTICE

This study contributes to the evidence base for self-management of early kidney disease. Although the exact reason for reduced BP in the intervention group is unclear, the importance of practitioner understanding of kidney disease management and patient understanding of BP medication are likely to be the contributing factors.

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.

A multicenter, phased, cluster-randomized controlled trial to reduce central line-associated bloodstream infections in intensive care units*

OBJECTIVES

To determine the causal effects of an intervention proven effective in pre-post studies in reducing central line-associated bloodstream infections in the intensive care unit.

DESIGN

We conducted a multicenter, phased, cluster-randomized controlled trial in which hospitals were randomized into two groups. The intervention group started in March 2007 and the control group started in October 2007; the study period ended September 2008. Baseline data for both groups are from 2006.

SETTING

Forty-five intensive care units from 35 hospitals in two Adventist healthcare systems.

INTERVENTIONS

A multifaceted intervention involving evidence-based practices to prevent central line-associated bloodstream infections and the Comprehensive Unit-based Safety Program to improve safety, teamwork, and communication.

MEASUREMENTS AND RESULTS

We measured central line-associated bloodstream infections per 1,000 central line days and reported quarterly rates. Baseline average central line-associated bloodstream infections per 1,000 central line days was 4.48 and 2.71, for the intervention and control groups (p = .28), respectively. By October to December 2007, the infection rate declined to 1.33 in the intervention group compared to 2.16 in the control group (adjusted incidence rate ratio 0.19; p = .003; 95% confidence interval 0.06-0.57). The intervention group sustained rates <1/1,000 central line days at 19 months (an 81% reduction). The control group also reduced infection rates to <1/1,000 central line days (a 69% reduction) at 12 months.

CONCLUSIONS

This study demonstrated a causal relationship between the multifaceted intervention and the reduced central line-associated bloodstream infections. Both groups decreased infection rates after implementation and sustained these results over time, replicating the results found in previous, pre-post studies of this multifaceted intervention and providing further evidence that most central line-associated bloodstream infections are preventable.

Calculating sample sizes for cluster randomized trials: we can keep it simple and efficient!

OBJECTIVE

Simple guidelines for calculating efficient sample sizes in cluster randomized trials with unknown intraclass correlation (ICC) and varying cluster sizes.

METHODS

A simple equation is given for the optimal number of clusters and sample size per cluster. Here, optimal means maximizing power for a given budget or minimizing total cost for a given power. The problems of cluster size variation and specification of the ICC of the outcome are solved in a simple yet efficient way.

RESULTS

The optimal number of clusters goes up, and the optimal sample size per cluster goes down as the ICC goes up or as the cluster-to-person cost ratio goes down. The available budget, desired power, and effect size only affect the number of clusters and not the sample size per cluster, which is between 7 and 70 for a wide range of cost ratios and ICCs. Power loss because of cluster size variation is compensated by sampling 10% more clusters. The optimal design for the ICC halfway the range of realistic ICC values is a good choice for the first stage of a two-stage design. The second stage is needed only if the first stage shows the ICC to be higher than assumed.

CONCLUSION

Efficient sample sizes for cluster randomized trials are easily computed, provided the cost per cluster and cost per person are specified.

Allocation techniques for balance at baseline in cluster randomized trials: a methodological review

Reviews have repeatedly noted important methodological issues in the conduct and reporting of cluster randomized controlled trials (C-RCTs). These reviews usually focus on whether the intracluster correlation was explicitly considered in the design and analysis of the C-RCT. However, another important aspect requiring special attention in C-RCTs is the risk for imbalance of covariates at baseline. Imbalance of important covariates at baseline decreases statistical power and precision of the results. Imbalance also reduces face validity and credibility of the trial results. The risk of imbalance is elevated in C-RCTs compared to trials randomizing individuals because of the difficulties in recruiting clusters and the nested nature of correlated patient-level data. A variety of restricted randomization methods have been proposed as way to minimize risk of imbalance. However, there is little guidance regarding how to best restrict randomization for any given C-RCT. The advantages and limitations of different allocation techniques, including stratification, matching, minimization, and covariate-constrained randomization are reviewed as they pertain to C-RCTs to provide investigators with guidance for choosing the best allocation technique for their trial.

The prevention access and risk taking in young people (PARTY) project protocol: a cluster randomised controlled trial of health risk screening and motivational interviewing for young people presenting to general practice

BACKGROUND

There are growing worldwide concerns about the ability of primary health care systems to manage the major burden of illness in young people. Over two thirds of premature adult deaths result from risks that manifest in adolescence, including injury, neuropsychiatric problems and consequences of risky behaviours. One policy response is to better reorientate primary health services towards prevention and early intervention. Currently, however, there is insufficient evidence to support this recommendation for young people. This paper describes the design and implementation of a trial testing an intervention to promote psychosocial risk screening of all young people attending general practice and to respond to identified risks using motivational interviewing.

MAIN OUTCOMES

clinicians' detection of risk-taking and emotional distress, young people's intention to change and reduction of risk taking.

SECONDARY OUTCOMES

pathways to care, trust in the clinician and likelihood of returning for future visits. The design of the economic and process evaluation are not detailed in this protocol.

METHODS

PARTY is a cluster randomised trial recruiting 42 general practices in Victoria, Australia. Baseline measures include: youth friendly practice characteristics; practice staff's self-perceived competency in young people's care and clinicians' detection and response to risk taking behaviours and emotional distress in 14-24 year olds, attending the practice. Practices are then stratified by a social disadvantage index and billing methods and randomised. Intervention practices receive: nine hours of training and tools; feedback of their baseline data and two practice visits over six weeks. Comparison practices receive a three hour seminar in youth friendly practice only. Six weeks post-intervention, 30 consecutive young people are interviewed post-consultation from each practice and followed-up for self-reported risk taking behaviour and emotional distress three and 12 months post consultation.

DISCUSSION

The PARTY trial is the first to examine the effectiveness and efficiency of a psychosocial risk screening and counselling intervention for young people attending primary care. It will provide important data on health risk profiles of young people attending general practice and on the effects of the intervention on engagement with primary care and health outcomes over 12 months.

TRIAL REGISTRATION

ISRCTN16059206.

Quality of cluster randomized controlled trials in oral health: a systematic review of reports published between 2005 and 2009

OBJECTIVES

To assess the quality of methods and reporting of recently published cluster randomized trials (CRTs) in oral health.

METHODS

We searched PubMed for CRTs that included at least one oral health-related outcome and were published from 2005 to 2009 inclusive. We developed a list of criteria for assessing trial quality and reporting. This was influenced largely by the extended CONSORT statement for CRTs but also included criteria suggested by other authors. We examined the extent to which trials were consistent with these criteria.

RESULTS

Twenty-three trials were included in the review. In 15 (65%) trials, clustering had been accounted for in sample size calculations, and in 18 (78%) authors had accounted for clustering in analysis. Intraclass correlation coefficients (ICCs) were reported for eight (35%) trials; the outcome assessor was reported as having been blinded to allocation in 12 (52%) trials; 17 (74%) described eligibility criteria at individual level, but only nine (39%) described such criteria at cluster level. Sixteen of 20 trials (80%), in which individuals were recruited, reported that individual informed consent was obtained.

CONCLUSIONS

These results suggest that the quality of recent CRTs in oral health is relatively high and appears to compare favourably with other fields. However, there remains room for improvement. Authors of future trials should endeavour to ensure sample size calculations and analyses properly account for clustering (and are reported as such), consider the potential for recruitment/identification bias at the design stage, describe the steps taken to avoid this in the final report and report observed ICCs and cluster-level eligibility criteria.

Implementation of AF-CBT by community practitioners serving child welfare and mental health: a randomized trial

The Partnerships for Families project is a randomized clinical trial designed to evaluate the implementation of Alternatives for Families: A Cognitive-Behavioral Therapy (AF-CBT), an evidence-based treatment for family conflict, coercion, and aggression, including child physical abuse. To evaluate the effectiveness of a training program in this model, 182 community practitioners from 10 agencies were randomized to receive AF-CBT training (n = 90) using a learning community model (workshops, consultation visits) or Training as Usual (TAU; n = 92) which provided trainings per agency routine. Practitioners completed self-report measures at four time points (0, 6, 12, and 18 months following baseline). Of those assigned to AF-CBT, 89% participated in at least one training activity and 68% met a "training completion" definition. A total of 80 (44%) practitioners were still active clinicians in the study by 18-month assessment in that they had not met our staff turnover or study withdrawal criteria. Using an intent-to-train design, hierarchical linear modeling analyses revealed significantly greater initial improvements for those in the AF-CBT training condition (vs. TAU condition) in CBT-related knowledge and use of AF-CBT teaching processes, abuse-specific skills, and general psychological skills. In addition, practitioners in both groups reported significantly more negative perceptions of organizational climate through the intervention phase. These significant, albeit modest, findings are discussed in the context of treatment training, research, and work force issues as they relate to the diverse backgrounds, settings, and populations served by community practitioners.

Feasibility and potential effectiveness of a non-pharmacological multidisciplinary care programme for persons with generalised osteoarthritis: a randomised, multiple-baseline single-case study

OBJECTIVES

To evaluate the feasibility and potential effectiveness of a 12-week, non-pharmacological multidisciplinary intervention in patients with generalised osteoarthritis (GOA).

DESIGN

A randomised, concurrent, multiple-baseline single-case design. During the baseline period, the intervention period and the postintervention period, all participants completed several health outcomes twice a week on Visual Analogue Scales.

SETTING

Rheumatology outpatient department of a specialised hospital in the Netherlands.

PARTICIPANTS

1 man and four women (aged 51-76 years) diagnosed with GOA.

PRIMARY OUTCOME MEASURES

To assess feasibility, the authors assessed the number of dropouts and adverse events, adherence rates and patients' satisfaction.

SECONDARY OUTCOME MEASURES

To assess the potential effectiveness, the authors assessed pain and self-efficacy using visual data inspection and randomisation tests.

RESULTS

The intervention was feasible in terms of adverse events (none) and adherence rate but not in terms of participants' satisfaction with the intervention. Visual inspection of the data and randomisation testing demonstrated no effects on pain (p=0.93) or self-efficacy (p=0.85).

CONCLUSIONS

The results of the present study indicate that the proposed intervention for patients with GOA was insufficiently feasible and effective. The data obtained through this multiple-baseline study have highlighted several areas in which the therapy programme can be optimised.

Cluster randomised trials

Although randomised controlled trials are the reference methodology to assess the effects of therapeutic interventions, for interventions that naturally occur in groups of individuals random allocation of participants may be inappropriate. In these cases, the unit of random allocation may be the group or cluster, rather than the individual. Clinical trials that randomly allocate groups or clusters of individuals are called cluster randomised trials. This article briefly presents the main implications of cluster randomisation with respect to the following methodological aspects: generalisability, concealment of allocation, comparability at baseline, blindness, loss of clusters and intra-class correlation.

Impact of CONSORT extension for cluster randomised trials on quality of reporting and study methodology: review of random sample of 300 trials, 2000-8

OBJECTIVE

To assess the impact of the 2004 extension of the CONSORT guidelines on the reporting and methodological quality of cluster randomised trials.

DESIGN

Methodological review of 300 randomly sampled cluster randomised trials. Two reviewers independently abstracted 14 criteria related to quality of reporting and four methodological criteria specific to cluster randomised trials. We compared manuscripts published before CONSORT (2000-4) with those published after CONSORT (2005-8). We also investigated differences by journal impact factor, type of journal, and trial setting.

DATA SOURCES

A validated Medline search strategy. Eligibility criteria for selecting studies Cluster randomised trials published in English language journals, 2000-8.

RESULTS

There were significant improvements in five of 14 reporting criteria: identification as cluster randomised; justification for cluster randomisation; reporting whether outcome assessments were blind; reporting the number of clusters randomised; and reporting the number of clusters lost to follow-up. No significant improvements were found in adherence to methodological criteria. Trials conducted in clinical rather than non-clinical settings and studies published in medical journals with higher impact factor or general medical journals were more likely to adhere to recommended reporting and methodological criteria overall, but there was no evidence that improvements after publication of the CONSORT extension for cluster trials were more likely in trials conducted in clinical settings nor in trials published in either general medical journals or in higher impact factor journals.

CONCLUSION

The quality of reporting of cluster randomised trials improved in only a few aspects since the publication of the extension of CONSORT for cluster randomised trials, and no improvements at all were observed in essential methodological features. Overall, the adherence to reporting and methodological guidelines for cluster randomised trials remains suboptimal, and further efforts are needed to improve both reporting and methodology.

Efficient design of cluster randomized and multicentre trials with unknown intraclass correlation

For cluster randomized and multicentre trials evaluating the effect of a treatment on persons nested within clusters, equations have been published to compute the optimal sample sizes at the cluster and person level as a function of sampling costs and intraclass correlation ( ICC). Here, optimal means maximum power and precision for a given sampling budget, or minimum sampling costs for a given power and precision. However, the ICC is usually unknown, and the optimal sample sizes depend strongly on this ICC. To overcome this local optimality problem, this study presents Maximin designs (MMDs) based on relative efficiency (RE) and efficiency. These designs perform well over a range of possible ICC values either in terms of RE compared with the locally optimal designs, or in terms of minimum efficiency (maximum variance) of the treatment effect estimator. The use of MMDs is illustrated using information from many cluster randomized trials in primary care. It is concluded that MMDs and the optimal design for an ICC halfway its assumed range are efficient for a range of ICC values and recommendable for practical use. This requires that trial reports mention the study cost per cluster and person.

Characteristics and quality of reporting of cluster randomized trials in children: reporting needs improvement

OBJECTIVE

To describe the characteristics and quality of reporting of cluster randomized trials (CRTs) in children published from 2004 to 2010.

STUDY DESIGN AND SETTING

Four databases were searched for reports of CRTs in children (0-18 years). Characteristics of the studies were summarized and the quality of reporting assessed using consolidated standards of reporting trial-CRT (CONSORT-CRT).

RESULTS

Of 1,949 identified references, 106 were included. The number of published CRTs in children increased since 2004. The greatest proportion of CRTs was undertaken in Europe (29%), whereas 40% was conducted in low- and middle-income countries. Most studies were of complex rather than simple interventions (83%); were preventive rather than treatment interventions (76%); and most frequently addressed infectious disease (21%), diet/physical activity interventions (19%), health-risk behaviors (15%), and undernutrition (13%). The majority used schools as units of randomization (72%) and enrolled 1,000-10,000 children per study (51%). Reporting was generally poor, with 34% of CRTs inadequately reporting on more than half of the CONSORT-CRT criteria. Although 85% of CRTs reported that they had ethics approval for the study, consent or assent was not obtained from children in most studies.

CONCLUSION

Children-specific elements of reporting are needed to improve the quality of reporting of CRTs and consequently their planning and implementation.

Primary school interventions to promote fruit and vegetable consumption: a systematic review and meta-analysis

OBJECTIVE

The consumption of fruits and vegetables (FV) may contribute to the prevention of many diseases. However, children at school age do not eat an enough amount of those foods. We have systematically reviewed the literature to assess the effectiveness of school interventions for promoting the consumption of FV.

METHODS

We performed a search in MEDLINE, EMBASE, CINAHL and CENTRAL. We pooled results and stratified the analysis according to type of intervention and study design.

RESULTS

Nineteen cluster studies were included. Most studies did not describe randomization method and did not take the cluster's effect into account. Pooled results of two randomized controlled trials (RCTs) of computer-based interventions showed effectiveness in improving consumption of FV [Standardized Mean Difference (SMD) 0.33 (95% CI 0.16, 0.50)]. No significant differences were found in pooled analysis of seven RCTs of multicomponent interventions or pooling results of two RCTs evaluating free/subsidized FV interventions.

CONCLUSIONS

Meta-analysis shows that computer-based interventions were effective in increasing FV consumption. Multicomponent interventions and free/subsidized FV interventions were not effective. Improvements in methodology are needed in future cluster studies. Although these results are preliminary, computer-based interventions could be considered in schools, given that they are effective and cheaper than other alternatives.

Statistical methods for cost-effectiveness analyses that use data from cluster randomized trials: a systematic review and checklist for critical appraisal

INTRODUCTION

The best data for cost-effectiveness analyses (CEAs) of group-level interventions often come from cluster randomized trials (CRTs), where randomization is by cluster (e.g., the hospital attended), not by individual.

METHODS

for these CEAs need to recognize both the correlation between costs and outcomes and that these data may be dependent on the cluster. General checklists and methodological guidance for critically appraising CEA ignore these issues. This article develops a new checklist and applies it in a systematic review of CEAs that use CRTs.

METHODS

The authors developed a checklist for CEAs that use CRTs, informed by a conceptual review of statistical methods. This checklist included criteria such as whether the analysis allowed for both clustering and the correlation between individuals' costs and outcomes. The authors undertook a systematic literature review of full economic evaluations that used CRTs. The quality of studies was assessed with the new checklist and by the "Drummond checklist."

RESULTS

The authors identified 62 papers that met the inclusion criteria. On average, studies satisfied 9 of the 10 criteria for the checklist but only 20% of criteria for the new checklist. More than 40% of studies adopted statistical methods that completely ignored clustering, and 75% disregarded any correlation between costs and outcomes. Only 4 studies employed appropriate statistical methods that allowed for both clustering and correlation.

CONCLUSIONS

Most economic evaluations that use data from CRTs ignored clustering or correlation. Statistical methods that address these issues are available, and their use should be encouraged. The new checklist can supplement generic CEA guidelines and highlight where research practice can be improved.

The role of gender in a smoking cessation intervention: a cluster randomized clinical trial

BACKGROUND

The prevalence of smoking in Spain is high in both men and women. The aim of our study was to evaluate the role of gender in the effectiveness of a specific smoking cessation intervention conducted in Spain.

METHODS

This study was a secondary analysis of a cluster randomized clinical trial in which the randomization unit was the Basic Care Unit (family physician and nurse who care for the same group of patients). The intervention consisted of a six-month period of implementing the recommendations of a Clinical Practice Guideline. A total of 2,937 current smokers at 82 Primary Care Centers in 13 different regions of Spain were included (2003-2005). The success rate was measured by a six-month continued abstinence rate at the one-year follow-up. A logistic mixed-effects regression model, taking Basic Care Units as random-effect parameter, was performed in order to analyze gender as a predictor of smoking cessation.

RESULTS

At the one-year follow-up, the six-month continuous abstinence quit rate was 9.4% in men and 8.5% in women (p = 0.400). The logistic mixed-effects regression model showed that women did not have a higher odds of being an ex-smoker than men after the analysis was adjusted for confounders (OR adjusted = 0.9, 95% CI = 0.7-1.2).

CONCLUSIONS

Gender does not appear to be a predictor of smoking cessation at the one-year follow-up in individuals presenting at Primary Care Centers. CLINICALTRIALS.GOV IDENTIFIER: NCT00125905.

Cluster randomised trial in the General Practice Research Database: 1. Electronic decision support to reduce antibiotic prescribing in primary care (eCRT study)

Background

The purpose of this research is to develop and evaluate methods for conducting cluster randomised trials in a primary care database that contains electronic patient records for large numbers of family practices. Cluster randomised trials are trials in which the units allocated represent groups of individuals, in this case family practices and their registered patients. Cluster randomised trials often suffer from the limitation that they include too few clusters, leading to problems of insufficient power and only imprecise estimation of the intraclass correlation coefficient, a key design parameter. This difficulty might be overcome by utilising databases that already hold electronic patient records for large numbers of practices. The protocol describes one application: a study of antibiotic prescribing for acute respiratory infection; a second protocol outlines an intervention in a less frequent chronic condition of public health importance, stroke.

Methods/Design

The objective of the study is to implement a cluster randomised trial to test the effectiveness of an electronic record-based intervention at achieving a reduction in antibiotic prescribing at consultations for respiratory illness in patients aged 18 and 59 years old in intervention family practices as compared with controls. Family practices will be recruited from the practices that presently contribute data to the UK General Practice Research Database (GPRD). Following randomisation, electronic prompts will be installed remotely at intervention practices to promote adherence with evidence-based standards of medical practice. The intervention was developed through qualitative research at non-intervention practices. Data for outcome assessment will be obtained from anonymised electronic patient records that are routinely collected into GPRD. This protocol outlines the proposed study designs, data sources, sample size requirements, analysis methods and dissemination plans. Ethical issues are also discussed.

Discussion

Results from this study will provide methodological evidence concerning the use of electronic patient records and databases for implementing cluster randomised trials in primary care. The study will also provide substantive findings in respect of electronic record-based interventions to reduce antibiotic prescribing in primary care.

Trial Registration

Current Controlled Trials ISRCTN 47558792.

Recruitment difficulties in a primary care cluster randomised trial: investigating factors contributing to general practitioners' recruitment of patients

Background

Recruitment of patients by health professionals is reported as one of the most challenging steps when undertaking studies in primary care settings. Numerous investigations of the barriers to patient recruitment in trials which recruit patients to receive an intervention have been published. However, we are not aware of any studies that have reported on the recruitment barriers as perceived by health professionals to recruiting patients into cluster randomised trials where patients do not directly receive an intervention. This particular subtype of cluster trial is commonly termed a professional-cluster trial. The aim of this study was to investigate factors that contributed to general practitioners recruitment of patients in a professional-cluster trial which evaluated the effectiveness of an intervention to increase general practitioners adherence to a clinical practice guideline for acute low-back pain.

Method

General practitioners enrolled in the study were posted a questionnaire, consisting of quantitative items and an open-ended question, to assess possible reasons for poor patient recruitment. Descriptive statistics were used to summarise quantitative items and responses to the open-ended question were coded into categories.

Results

Seventy-nine general practitioners completed at least one item (79/94 = 84%), representing 68 practices (85% practice response rate), and 44 provided a response to the open-ended question. General practitioners recalled inviting a median of two patients with acute low-back pain to participate in the trial over a seven-month period; they reported that they intended to recruit patients, but forgot to approach patients to participate; and they did not perceive that patients had a strong interest or disinterest in participating. Additional open-ended comments were generally consistent with the quantitative data.

Conclusion

A number of barriers to the recruitment of patients with acute low-back pain by general practitioners in a professional-cluster trial were identified. These barriers were similar to those that have been identified in the literature surrounding the recruitment of patients in individual patient randomised trials. To advance the evidence base for patient recruitment strategies in primary care settings, trialists undertaking professional-cluster trials need to develop and evaluate patient recruitment strategies that minimise the efforts required by practice staff to recruit patients, while also meeting privacy and ethical responsibilities and minimising the risk of selection bias.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN012606000098538 (date registered 14/03/2006).

Anger management for people with mild to moderate learning disabilities: study protocol for a multi-centre cluster randomized controlled trial of a manualized intervention delivered by day-service staff

BACKGROUND

Cognitive behaviour therapy (CBT) is the treatment of choice for common mental health problems, but this approach has only recently been adapted for people with learning disabilities, and there is a limited evidence base for the use of CBT with this client group. Anger treatment is the one area where there exists a reasonable number of small controlled trials. This study will evaluate the effectiveness of a manualized 12-week CBT intervention for anger. The intervention will be delivered by staff working in the day services that the participants attend, following training to act as 'lay therapists' by a Clinical Psychologist, who will also provide supervision.

METHODS/DESIGN

This is a multi-centre cluster randomized controlled trial of a group intervention versus a 'support as usual' waiting-list control group, with randomization at the level of the group. Outcomes will be assessed at the end of the intervention and again 6-months later. After completion of the 6-month follow-up assessments, the intervention will also be delivered to the waiting-list groups. The study will include a range of anger/aggression and mental health measures, some of which will be completed by service users and also by their day service key-workers and by home carers. Qualitative data will be collected to assess the impact of the intervention on participants, lay therapists, and services, and the study will also include a service-utilization cost and consequences analysis.

DISCUSSION

This will be the first trial to investigate formally how effectively staff working in services providing day activities for people with learning disabilities are able to use a therapy manual to deliver a CBT based anger management intervention, following brief training by a Clinical Psychologist. The demonstration that service staff can successfully deliver anger management to people with learning disabilities, by widening the pool of potential therapists, would have very significant benefits in relation to the current policy of improving access to psychological therapies, in addition to addressing more effectively an important and often unmet need of this vulnerable client group. The economic analysis will identify the direct and indirect costs (and/or savings) of the intervention and consider these in relation to the range of observed effects. The qualitative analyses will enhance the interpretation of the quantitative data, and if the study shows positive results, will inform the roll-out of the intervention to the wider community.

TRIAL REGISTRATION

ISRCTN: ISRCTN37509773.

The OPERA trial: protocol for a randomised trial of an exercise intervention for older people in residential and nursing accommodation

Abstract

Trial Registration

[ISRCTN: ISRCTN43769277]

Selection effects may account for better outcomes of the German Disease Management Program for type 2 diabetes

Background

The nationwide German disease management program (DMP) for type 2 diabetes was introduced in 2003. Meanwhile, results from evaluation studies were published, but possible baseline differences between DMP and usual-care patients have not been examined. The objective of our study was therefore to find out if patient characteristics as socio-demographic variables, cardiovascular risk profile or motivation for life style changes influence the chance of being enrolled in the German DMP for type 2 diabetes and may therefore account for outcome differences between DMP and usual-care patients.

Methods

Case control study comparing DMP patients with usual-care patients at baseline and follow up; mean follow-up period of 36 ± 14 months. We used chart review data from 51 GP surgeries. Participants were 586 DMP and 250 usual-care patients with type 2 diabetes randomly selected by chart registry. Data were analysed by multivariate logistic and linear regression analyses. Significance levels were p ≤ 0.05.

Results

There was a better chance for enrolment if patients a) had a lower risk status for diabetes complications, i.e. non-smoking (odds ratio of 1.97, 95% confidence interval of 1.11 to 3.48) and lower systolic blood pressure (1.79 for 120 mmHg vs. 160 mmHg, 1.15 to 2.81); b) had higher activity rates, i.e. were practicing blood glucose self-monitoring (1.67, 1.03 to 2.76) and had been prescribed a diabetes patient education before enrolment (2.32, 1.29 to 4.19) c) were treated with oral medication (2.17, 1.35 to 3.49) and d) had a higher GP-rated motivation for diabetes education (4.55 for high motivation vs. low motivation, 2.21 to 9.36).

Conclusions

At baseline, future DMP patients had a lower risk for diabetes complications, were treated more intensively and were more active and motivated in managing their disease than usual-care patients. This finding a) points to the problem that the German DMP may not reach the higher risk patients and b) selection bias may impair the assessment of differences in outcome quality between enrolled and usual-care patients. Suggestions for dealing with this bias in evaluation studies are being made.