Collating the knowledge base for core outcome set development: developing and appraising the search strategy for a systematic review

Protocols Targeting Afferent Pathways via Neuromuscular Electrical Stimulation for the Plantar Flexors: A Systematic Review

This systematic review documents the protocol characteristics of studies that used neuromuscular electrical stimulation protocols (NMES) on the plantar flexors [through triceps surae (TS) or tibial nerve (TN) stimulation] to stimulate afferent pathways. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, was registered to PROSPERO (ID: CRD42022345194) and was funded by the Greek General Secretariat for Research and Technology (ERA-NET NEURON JTC 2020). Included were original research articles on healthy adults, with NMES interventions applied on TN or TS or both. Four databases (Cochrane Library, PubMed, Scopus, and Web of Science) were systematically searched, in addition to a manual search using the citations of included studies. Quality assessment was conducted on 32 eligible studies by estimating the risk of bias with the checklist of the Effective Public Health Practice Project Quality Assessment Tool. Eighty-seven protocols were analyzed, with descriptive statistics. Compared to TS, TN stimulation has been reported in a wider range of frequencies (5-100, vs. 20-200 Hz) and normalization methods for the contraction intensity. The pulse duration ranged from 0.2 to 1 ms for both TS and TN protocols. It is concluded that with increasing popularity of NMES protocols in intervention and rehabilitation, future studies may use a wider range of stimulation attributes, to stimulate motor neurons via afferent pathways, but, on the other hand, additional studies may explore new protocols, targeting for more optimal effectiveness. Furthermore, future studies should consider methodological issues, such as stimulation efficacy (e.g., positioning over the motor point) and reporting of level of discomfort during the application of NMES protocols to reduce the inherent variability of the results.

Literature searching methods or guidance and their application to public health topics: A narrative review

Background

Information specialists conducting searches for systematic reviews need to consider key questions around which and how many sources to search. This is particularly important for public health topics where evidence may be found in diverse sources.

Objectives

The objective of this review is to give an overview of recent studies on information retrieval guidance and methods that could be applied to public health evidence and used to guide future searches.

Methods

A literature search was performed in core databases and supplemented by browsing health information journals and citation searching. Results were sifted and reviewed.

Results

Seventy‐two papers were found and grouped into themes covering sources and search techniques. Public health topics were poorly covered in this literature.

Discussion

Many researchers follow the recommendations to search multiple databases. The review topic influences decisions about sources. Additional sources covering grey literature eliminate bias but are time‐consuming and difficult to search systematically. Public health searching is complex, often requiring searches in multidisciplinary sources and using additional methods.

Conclusions

Search planning is advisable to enable decisions about which and how many sources to search. This could improve with more work on modelling search scenarios, particularly in public health topics, to examine where publications were found and guide future research.

Development of an efficient search filter to retrieve systematic reviews from PubMed

Objective:

Locating systematic reviews is essential for clinicians and researchers when creating or updating reviews and for decision-making in health care. This study aimed to develop a search filter for retrieving systematic reviews that improves upon the performance of the PubMed systematic review search filter.

Methods:

Search terms were identified from abstracts of reviews published in Cochrane Database of Systematic Reviews and the titles of articles indexed as systematic reviews in PubMed. Both the precision of the candidate terms and the number of systematic reviews retrieved from PubMed were evaluated after excluding the subset of articles retrieved by the PubMed systematic review filter. Terms that achieved a precision greater than 70% and relevant publication types indexed with MeSH terms were included in the filter search strategy.

Results:

The search strategy used in our filter added specific terms not included in PubMed's systematic review filter and achieved a 61.3% increase in the number of retrieved articles that are potential systematic reviews. Moreover, it achieved an average precision that is likely greater than 80%.

Conclusions:

The developed search filter will enable users to identify more systematic reviews from PubMed than the PubMed systematic review filter with high precision.

Developing a core outcome set for paediatric wrist fractures: a systematic review of prior outcomes

Objectives

This review aims to summarize the outcomes used to describe effectiveness of treatments for paediatric wrist fractures within existing literature.

Method

We searched the Cochrane Library, Scopus, and Ovid Medline for studies pertaining to paediatric wrist fractures. Three authors independently identified and reviewed eligible studies. This resulted in a list of outcome domains and outcomes measures used within clinical research. Outcomes were mapped onto domains defined by the COMET collaborative.

Results

Our search terms identified 4,262 different papers. Screening of titles excluded 2,975, leaving 1,287 papers to be assessed for eligibility. Of this 1,287, 30 studies were included for full analysis. Overall, five outcome domains, 16 outcome measures, and 28 measurement instruments were identified as outcomes within these studies. 24 studies used at least one measurement pertaining to the physiological/clinical outcome domain. The technical, life impact, and adverse effect domains were recorded in 23, 20, and 11 of the studies respectively. Within each domain it was common for different measurement instruments to be used to assess each outcome measure. The most commonly reported outcome measures were range of movement, a broad array of “radiological measures” and pain intensity, which were used in 24, 23, and 12 of the 30 studies.

Conclusion

This study highlights the heterogeneity in outcomes reported within clinical effectiveness studies of paediatric wrist fractures. We provided an overview of the types of outcomes reported in paediatric wrist fracture studies and identified a list of potentially relevant outcomes required for the development of a core outcome set.

Choosing important health outcomes for comparative effectiveness research: 5th annual update to a systematic review of core outcome sets for research

BACKGROUND

A systematic review of core outcome sets (COS) for research is updated annually to populate an online database. It is a resource intensive review to do annually but automation techniques have potential to aid the process. The production of guidance and standards in COS development means that there is now an expectation that COS are being developed and reported to a higher standard. This is the fifth update to the systematic review and will explore these issues.

METHODS

Searches were carried out to identify studies published or indexed in 2018. Automated screening methods were used to rank the citations in order of relevance. The cut-off for screening was set to the top 25% in ranked priority order, following development and validation of the algorithm. Studies were eligible for inclusion if they reported the development of a COS, regardless of any restrictions by age, health condition or setting. COS were assessed against each of the Core Outcome Set-STAndards for Development (COS-STAD).

RESULTS

Thirty studies describing the development of 44 COS were included in this update. Six COS (20%) were deemed to have met all 12 criteria representing the 11 minimum standards for COS development (range = 4 to 12 criteria, median = 10 criteria). All 30 COS studies met all four minimum standards for scope. Twenty-one (70%) COS met all three minimum standards for stakeholders. Twenty-three studies (77%) included patients with the condition or their representatives. The number of countries involved in the development of COS ranged from 1 to 39 (median = 10). Six studies (20%) met all four minimum standards [five criteria] for the consensus process.

CONCLUSION

Automated ranking was successfully used to assist the screening process and reduce the workload of this systematic review update. With the provision of guidelines, COS are better reported and being developed to a higher standard.

Outcome and comparator choice in molar incisor hypomineralisation (MIH) intervention studies: a systematic review and social network analysis

OBJECTIVES

Outcome and comparator choice strongly determine the validity and implementation of clinical trial results. We aimed to assess outcome and comparator choice in intervention studies on molar incisor hypomineralisation (MIH) using systematic review and social network analysis (SNA).

DESIGN AND DATA SOURCES

Medline, Embase, Cochrane Central, Google Scholar, opengrey.eu as well as DRKS.de and Clinicaltrials.gov were searched for MIH intervention studies. The search covered the period from 1980 to 2019.

ELIGIBILITY CRITERIA

Clinical single-arm/multiarm, controlled/uncontrolled studies reporting on the management of MIH were included. Reported outcomes and comparators were extracted and categorised. SNA was used to evaluate comparator choice and the resulting trial networks.

DATA EXTRACTION

Of the 7979 identified records, 100 were evaluated in full text and 35 studies (17 randomised controlled trials, 14 prospective and 4 retrospective cohort studies) were included.

RESULTS

In total, 2124 patients with a mean age of 11 years (min/max 6/70 years) were included. Outcomes fell in one of 11 different outcome categories: restoration success, aesthetic improvement, pain/hypersensitivity/discomfort, mineral gain, space management, anaesthesia effectiveness, preventive success, efficiency, quality of life, gingival and periodontal health and patient satisfaction. Comparators were mainly restorative interventions (17 studies), remineralisation (3), treatment of hypersensitivity (10), aesthetic interventions (5) and orthodontic interventions (3). Two highly clustered comparator networks emerged; many interventions were not robustly linked to these networks.

CONCLUSIONS

MIH intervention studies recorded both clinically centred and patient-centred outcomes. Core outcome set development should consider these and supplement them with outcomes on, for example, applicability. The high number of compared interventions tested in only few studies and our SNA results implicate that the current evidence may not be robust.

Evaluation of an automatic article selection method for timelier updates of the Comet Core Outcome Set database

Curated databases of scientific literature play an important role in helping researchers find relevant literature, but populating such databases is a labour intensive and time-consuming process. One such database is the freely accessible Comet Core Outcome Set database, which was originally populated using manual screening in an annually updated systematic review. In order to reduce the workload and facilitate more timely updates we are evaluating machine learning methods to reduce the number of references needed to screen. In this study we have evaluated a machine learning approach based on logistic regression to automatically rank the candidate articles. Data from the original systematic review and its four first review updates were used to train the model and evaluate performance. We estimated that using automatic screening would yield a workload reduction of at least 75% while keeping the number of missed references around 2%. We judged this to be an acceptable trade-off for this systematic review, and the method is now being used for the next round of the Comet database update.

Choosing important health outcomes for comparative effectiveness research: An updated systematic review and involvement of low and middle income countries

Background

Core outcome sets (COS) comprise a minimum set of outcomes that should be measured and reported in all trials for a specific health condition. The COMET (Core Outcome Measures in Effectiveness Trials) Initiative maintains an up to date, publicly accessible online database of published and ongoing COS. An annual systematic review update is an important part of this process.

Methods

This review employed the same, multifaceted approach that was used in the original review and the previous two updates. This approach has identified studies that sought to determine which outcomes/domains to measure in clinical trials of a specific condition. This update includes an analysis of the inclusion of participants from low and middle income countries (LMICs) as identified by the OECD, in these COS.

Results

Eighteen publications, relating to 15 new studies describing the development of 15 COS, were eligible for inclusion in the review. Results show an increase in the use of mixed methods, including Delphi surveys. Clinical experts remain the most common stakeholder group involved. Overall, only 16% of the 259 COS studies published up to the end of 2016 have included participants from LMICs.

Conclusion

This review highlights opportunities for greater public participation in COS development and the involvement of stakeholders from a wider range of geographical settings, in particular LMICs.

Outcomes in randomised controlled trials in prevention and management of carious lesions: a systematic review

Background

Inconsistent outcome reporting is one significant hurdle to combining results from trials into systematic reviews. Core outcome sets (COS) can reduce this barrier. The aim of this review was to map outcomes reported in caries prevention and management randomised controlled trials (RCT) as a first step to COS development. We also investigated RCT characteristics and reporting of primary outcomes and sample size calculations.

Methods

PubMed, Embase, Web of Knowledge and Cochrane CENTRAL were systematically searched (1 January 1968 to 25 August 2015). Inclusion criteria: RCTs comparing any technique for prevention or management of caries with another or placebo and RCTs comparing interventions to support patients undergoing treatment of caries (without setting, dentition or age restrictions). Categories were developed through piloting and group consensus and outcomes grouped accordingly.

Results

Of 4773 search results, 764 were potentially relevant, full text was available for 731 papers and 605 publications met the inclusion criteria and were included. For all outcomes across the time periods 1968–1980 and 2001–2010, reporting of outcome ‘caries experience’ reduced from 39% to 18%; ‘clinical performance of the restoration’ reporting increased from 33% to 42% although there was a reduction to 22% in 2011–2015. Emerging outcome domains include ‘lesion activity’ and ‘pulp health-related outcomes’, accounting for 1% and 0%, respectively, during 1968–1980 and 10% and 4% for 2011–2015. Reporting ‘resource efficiency’ and ‘quality of life measures’ have remained at a low level. No publications reported tooth survival independent of an index such as DMFT or equivalent. Primary outcomes were only identified as such in 414 (68%) of the reports.

Conclusions

Over the past 50 years, outcome reporting for trials on prevention and management of carious lesions have tended to focus on outcomes measuring caries experience and restoration material clinical performance with lesion activity and cost-effectiveness increasingly being reported. Patient-reported and patient-focused outcomes are becoming more common (although as secondary outcomes) but remain low in use. The challenge with developing a COS will be balancing commonly previously reported outcomes against those more relevant for the future.

Trial registration

PROSPERO, CRD42015025310. Registered on 14 August 2015, Trials (Schwendicke et al., Trials 16:397, 2015) and COMET initiative online (COMET, 2017).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2256-1) contains supplementary material, which is available to authorized users.

The COMET Handbook: version 1.0

The selection of appropriate outcomes is crucial when designing clinical trials in order to compare the effects of different interventions directly. For the findings to influence policy and practice, the outcomes need to be relevant and important to key stakeholders including patients and the public, health care professionals and others making decisions about health care. It is now widely acknowledged that insufficient attention has been paid to the choice of outcomes measured in clinical trials. Researchers are increasingly addressing this issue through the development and use of a core outcome set, an agreed standardised collection of outcomes which should be measured and reported, as a minimum, in all trials for a specific clinical area.Accumulating work in this area has identified the need for guidance on the development, implementation, evaluation and updating of core outcome sets. This Handbook, developed by the COMET Initiative, brings together current thinking and methodological research regarding those issues. We recommend a four-step process to develop a core outcome set. The aim is to update the contents of the Handbook as further research is identified.

Development of a core outcome set for clinical trials in childhood constipation: a study using a Delphi technique

OBJECTIVE

Patients, their parents and healthcare professionals (HCPs) have a different perception regarding the symptoms of functional constipation (FC). Consequently, a lack of agreement exists on definitions and outcomes used in therapeutic trials of FC. Therefore, our aim was to develop a core outcome set (COS) for FC for children aged 0-1 year and 1-18 years.

DESIGN AND SETTING

Prospective study design: primary, secondary and tertiary care settings.

METHODS

This COS was developed using a Delphi technique. First, HCPs, parents of children with FC and patients aged ≥12-18 years were asked to list up to five outcomes they considered relevant in the treatment of FC. Outcomes mentioned by >10% of participants were included in a shortlist. In the next phase, outcomes on this shortlist were rated and prioritised by HCPs, parents and patients. Outcomes with the highest scores were included in a draft COS. In a face-to-face expert meeting, the final COS was determined.

RESULTS

The first phase was completed by 109 HCPs, 165 parents and 50 children. Fifty HCPs, 80 parents and 50 children completed the subsequent phase. The response rate was between 63% and 100% in both steps. The final COS for all ages consisted of: defecation frequency, stool consistency, painful defecation, quality of life, side effects of treatment, faecal incontinence, abdominal pain and school attendance.

CONCLUSION

The use of this COS for FC will decrease study heterogeneity and improve comparability of studies. Therefore, researchers are recommended to use this COS in future therapeutic trials on childhood FC.

Choosing Important Health Outcomes for Comparative Effectiveness Research: An Updated Review and Identification of Gaps

Background

The COMET (Core Outcome Measures in Effectiveness Trials) Initiative promotes the development and application of core outcome sets (COS), including relevant studies in an online database. In order to keep the database current, an annual search of the literature is undertaken. This study aimed to update a previous systematic review, in order to identify any further studies where a COS has been developed. Furthermore, no prioritization for COS development has previously been undertaken, therefore this study also aimed to identify COS relevant to the world’s most prevalent health conditions.

Methods

The methods used in this updated review followed the same approach used in the original review and the previous update. A survey was also sent to the corresponding authors of COS identified for inclusion in this review, to ascertain what lessons they had learnt from developing their COS. Additionally, the COMET database was searched to identify COS that might be relevant to the conditions with the highest global prevalence.

Results

Twenty-five reports relating to 22 new studies were eligible for inclusion in the review. Further improvements were identified in relation to the description of the scope of the COS, use of the Delphi technique, and the inclusion of patient participants within the development process. Additionally, 33 published and ongoing COS were identified for 13 of the world’s most prevalent conditions.

Conclusion

The development of a reporting guideline and minimum standards should contribute towards future improvements in development and reporting of COS. This study has also described a first approach to identifying gaps in existing COS, and to priority setting in this area. Important gaps have been identified, on the basis of global burden of disease, and the development and application of COS in these areas should be considered a priority.

Dose-response relationship between dietary magnesium intake and cardiovascular mortality: A systematic review and dose-based meta-regression analysis of prospective studies

BACKGROUND

Although epidemiology studies have reported the relationship, including a dose-response relationship, between dietary magnesium intake and risk of cardiovascular disease (CVD), the risk for CVD mortality is inconclusive and the evidence for a dose-response relationship has not been summarized.

OBJECTIVE

We conducted a systematic review and meta-analysis of prospective studies to summarize the evidence regarding the association of dietary magnesium intake with risk of CVD mortality and describe their dose-response relationship.

DESIGN

We identified relevant studies by searching major scientific literature databases and grey literature resources from their inception to August 2015, and reviewed references lists of retrieved articles. We included population-based studies that reported mortality risks, i.e. relative risks (RRs), odds ratios (ORs) or hazard ratios (HRs) of CVD mortality or cause-specific CVD death. Linear dose-response relationships were assessed using random-effects meta-regression. Potential nonlinear associations were evaluated using restricted cubic splines.

RESULTS

Out of 3002 articles, 9 articles from 8 independent studies met the eligibility criteria. These studies comprised 449,748 individuals and 10,313 CVD deaths. Compared with the lowest dietary magnesium consumption group in the population, the risk of CVD mortality was reduced by 16% in women and 8% in men. No significant linear dose-response relationship was found between increment in dietary magnesium intake and CVD mortality across all the studies. After adjusting for age and BMI, the risk of CVD mortality was reduced by 24-25% per 100mg/d increment in dietary magnesium intake in women of all the participants and in all the US participants.

CONCLUSION

Although the combined data confirm the role of dietary magnesium intake in reducing CVD mortality, the dose-response relationship was only found among women and in US population.

Dose-Response Relationship between Dietary Magnesium Intake and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Regression Analysis of Prospective Cohort Studies

The epidemiological evidence for a dose-response relationship between magnesium intake and risk of type 2 diabetes mellitus (T2D) is sparse. The aim of the study was to summarize the evidence for the association of dietary magnesium intake with risk of T2D and evaluate the dose-response relationship. We conducted a systematic review and meta-analysis of prospective cohort studies that reported dietary magnesium intake and risk of incident T2D. We identified relevant studies by searching major scientific literature databases and grey literature resources from their inception to February 2016. We included cohort studies that provided risk ratios, i.e., relative risks (RRs), odds ratios (ORs) or hazard ratios (HRs), for T2D. Linear dose-response relationships were assessed using random-effects meta-regression. Potential nonlinear associations were evaluated using restricted cubic splines. A total of 25 studies met the eligibility criteria. These studies comprised 637,922 individuals including 26,828 with a T2D diagnosis. Compared with the lowest magnesium consumption group in the population, the risk of T2D was reduced by 17% across all the studies; 19% in women and 16% in men. A statistically significant linear dose-response relationship was found between incremental magnesium intake and T2D risk. After adjusting for age and body mass index, the risk of T2D incidence was reduced by 8%–13% for per 100 mg/day increment in dietary magnesium intake. There was no evidence to support a nonlinear dose-response relationship between dietary magnesium intake and T2D risk. The combined data supports a role for magnesium in reducing risk of T2D, with a statistically significant linear dose-response pattern within the reference dose range of dietary intake among Asian and US populations. The evidence from Europe and black people is limited and more prospective studies are needed for the two subgroups.

The contribution of databases to the results of systematic reviews: a cross-sectional study

BACKGROUND

One of the best sources for high quality information about healthcare interventions is a systematic review. A well-conducted systematic review includes a comprehensive literature search. There is limited empiric evidence to guide the extent of searching, in particular the number of electronic databases that should be searched. We conducted a cross-sectional quantitative analysis to examine the potential impact of selective database searching on results of meta-analyses.

METHODS

Our sample included systematic reviews (SRs) with at least one meta-analysis from three Cochrane Review Groups: Acute Respiratory Infections (ARI), Infectious Diseases (ID), Developmental Psychosocial and Learning Problems (DPLP) (n = 129). Outcomes included: 1) proportion of relevant studies indexed in each of 10 databases; and 2) changes in results and statistical significance of primary meta-analysis for studies identified in Medline only and in Medline plus each of the other databases.

RESULTS

Due to variation across topics, we present results by group (ARI n = 57, ID n = 38, DPLP n = 34). For ARI, identification of relevant studies was highest for Medline (85 %) and Embase (80 %). Restricting meta-analyses to trials that appeared in Medline + Embase yielded fewest changes in statistical significance: 53/55 meta-analyses showed no change. Point estimates changed in 12 cases; in 7 the change was less than 20 %. For ID, yield was highest for Medline (92 %), Embase (81 %), and BIOSIS (67 %). Restricting meta-analyses to trials that appeared in Medline + BIOSIS yielded fewest changes with 1 meta-analysis changing in statistical significance. Point estimates changed in 8 of 31 meta-analyses; change less than 20 % in all cases. For DPLP, identification of relevant studies was highest for Medline (75 %) and Embase (62 %). Restricting meta-analyses to trials that appeared in Medline + PsycINFO resulted in only one change in significance. Point estimates changed for 13 of 33 meta-analyses; less than 20 % in 9 cases.

CONCLUSIONS

Majority of relevant studies can be found within a limited number of databases. Results of meta-analyses based on the majority of studies did not differ in most cases. There were very few cases of changes in statistical significance. Effect estimates changed in a minority of meta-analyses but in most the change was small. Results did not change in a systematic manner (i.e., regularly over- or underestimating treatment effects), suggesting that selective searching may not introduce bias in terms of effect estimates.

Reporting on Outcome Measures of Functional Constipation in Children-A Systematic Review

OBJECTIVE

Standardized outcome measures provide a basis for comparing outcomes of different clinical trials. Consequently, they can serve as the foundation for determining which therapeutic interventions are most effective. The aim of the present study is to systematically assess how definitions and outcome measures are defined in therapeutic randomized controlled trials (RCTs) of children with functional constipation (FC).

METHODS

PubMed, EMBASE, and Cochrane databases were searched. Studies were included if it was a (systematic review of) therapeutic RCT, concerning children from 1 to 18 years old with FC, a definition of FC was provided, and if they were written in English. The Delphi list was used for quality assessment.

RESULTS

A total of 4092 articles were found but only 45 studies fulfilled our inclusion criteria. In these 45 trials, 22 different definitions of FC were used (17 studies used the Rome III-criteria), 27 different interventions were investigated, and 29 different definitions of treatment success were used. Thirty RCTs (57%) reported primary outcomes of which treatment success was the most frequently used. Most trials (80%) used parental diaries of which only 2 RCTs stated that their instrument was validated. Twenty-four trials (53%) were of good methodological quality.

CONCLUSIONS

Inconsistency and heterogeneity exist in definitions and outcome measures used in RCTs on childhood FC. Standard definitions, outcome measures, and also validated instruments are needed. We recommend the development of a minimum core outcome set for clinical research in children with FC to make comparison possible between the effects of different therapeutic interventions across studies.

Core outcome sets and systematic reviews

Systematic reviews seek to bring together research evidence to answer the question for the review. The reviewers usually wish to compare, contrast and, if appropriate, combine the findings of the existing research studies. However, these intentions are often thwarted by inconsistencies in the outcomes that were measured and reported in the individual studies. This, in turn, makes it difficult for readers of the review to use it to make informed decisions and choices about health and social care. One solution is for trials in a particular topic area to measure and report a standardised set of outcomes, which would then be used in the review. Core outcome sets are a means of doing this, providing an agreed standardised collection of outcomes for measuring and reporting for a specific area of health. In this commentary, we argue for greater involvement of systematic reviewers in the development and implementation of core outcome sets. This might help with, for example, the selection of outcomes to include in the Summary of findings tables that provide users of the review with the key quantitative findings. Consideration of core outcome sets when reviewers register their topics with Cochrane Review Groups or in PROSPERO would also help reviewers to plan their reviews. A greater uptake of core outcome sets across research, including systematic reviews, would help towards the ultimate aim of improving health and well-being through improving health and social care.

Choosing Important Health Outcomes for Comparative Effectiveness Research: An Updated Review and User Survey

BACKGROUND

A COS represents an agreed minimum set of outcomes that should be measured and reported in all trials of a specific condition. The COMET (Core Outcome Measures in Effectiveness Trials) initiative aims to collate and stimulate the development and application of COS, by including data on relevant studies within a publically available internet-based resource. In recent years, there has been an interest in increasing the development of COS. Therefore, this study aimed to provide an update of a previous review, and examine the quality of development of COS. A further aim was to understand the reasons why individuals are searching the COMET database.

METHODS

A multi-faceted search strategy was followed, in order to identify studies that sought to determine which outcomes/domains to measure in clinical trials of a specific condition. Additionally, a pop up survey was added to the COMET website, to ascertain why people were searching the COMET database.

RESULTS

Thirty-two reports relating to 29 studies were eligible for inclusion in the review. There has been an improvement in the description of the scope of a COS and an increase in the proportion of studies using literature/systematic reviews and the Delphi technique. Clinical experts continue to be the most common group involved in developing COS, however patient and public involvement has increased. The pop-up survey revealed the most common reasons for visiting the COMET website to be thinking about developing a COS and planning a clinical trial.

CONCLUSIONS

This update demonstrates that recent studies appear to have adopted a more structured approach towards COS development and public representation has increased. However, there remains a need for developers to adequately describe details about the scope of COS, and for greater public engagement. The COMET database appears to be a useful resource for both COS developers and users of COS.