Medline search validity for randomised controlled trials in different areas of dental research

Electronic search strategies fail to identify randomized controlled trials (RCTs) in neurosurgery

Randomized controlled trials (RCTs) are the gold standard studies to evaluate the efficacy of therapeutic interventions. Although they are frequently identified through open searches in electronic databases, no studies have evaluated how easy it is to identify RCTs in neurosurgery using electronic search strategies. The present study evaluated the sensitivity and specificity of different search strategies applied to commonly used databases to identify RCTs in neurosurgery. The total number of RCTs in neurosurgery published between 1960 and 2013 was determined through a detailed search involving open keyword searches in PubMed, Cochrane Library and Center for Reviews and Dissemination (CRD) databases, a PubMed search based on clinical entity-related keywords and hand-searches on the reference list of identified articles. The sensitivity and specificity were calculated for the open keyword searches on PubMed, the Cochrane Library and the CRD database and for the Cochrane's HSSS, based on the total number of the identified RCTs. Compared to the total of 1102 RCTs identified, PubMed open search yielded 4660 articles, among which 365 were RCTs (sensitivity: 33.1%; specificity: 7.8%). Cochrane open search yielded 621 among which 36 were RCTs (sensitivity: 3.2%; specificity: 5.8%) and CRD open search returned 78 articles, among which 4 were RCTs (sensitivity: 0.4% sensitivity; specificity: 5.1%). The Cochrane HSSS retrieved 10702 results, among which 340 were RCTs (sensitivity: 30.9%; specificity: 3.2%). Most RCTs in neurosurgery cannot be identified by commonly used search strategies, which emphasizes the need to improve their indexing.

Publication pattern, study design, authors and countries involved in orthodontic RCTs - a bibliometric MEDLINE survey over the past 50 years

OBJECTIVES

The objective of this study was to investigate the number and proportions, study design, journal publications, authors and countries involved in orthodontic randomised controlled trials (RCTs) over the past 50 years.

METHOD

A MEDLINE database search (Entrez PubMed, http://www.ncbi.nlm.nih.gov ) was performed in November 2018 for RCT publications from 1 January 1968 to 31 December 2017. All orthodontic publications, clinical trials (CTs) or RCTs were selected. For each year from 1968 to 2017, the total number of orthodontic publications and total number of CTs and RCTs were computed. Following this, study design, journal publications, authors and countries involved in orthodontic RCTs were noted.

RESULTS

The RCTs accounted for 0.1% of all orthodontic publications in the 1970s and 1980s, and, following this, the proportion of RCTs was increased and amounted to 2.7% over the past decade (2008-2017). The majority of RCTs were of single centre design (93.4%) and in 88.3% a parallel-arm design was performed. The United States and United Kingdom endorsed 16.9% and 15.5% of the RCTs, followed by Turkey (11.1%), Brazil (7.0%), Sweden (6.6%), China (5.6%), Italy (5.4%), and Germany (4.1%). Of all RCTs, 74.2% were published in 20 orthodontic journals and 25.8% in 81 non-orthodontic journals. The American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, European Journal of Orthodontics and Journal of Orthodontics contributed to 60.2% of all the RCTs.

CONCLUSION

The considerable increase in orthodontic RCTs over the past 50 years implies an increased scientific impact of orthodontic literature.

The effect of bias on the magnitude of clinical outcomes in periodontology: a pilot study

AIM

To investigate potential effect of bias on magnitude of outcomes.

MATERIAL AND METHODS

Randomized-controlled trials (RCTs) from the Cochrane Database of Systematic Reviews were searched. Methodological quality of RCTs was assessed in terms of allocation concealment and examiner masking. Meta-regression analyses were used to determine associations between the quality assessments and magnitude of treatment outcomes on probing depth and attachment level.

RESULTS

Thirty-five RCTs were identified from five systematic reviews. Adequate allocation concealment and examiner masking were found in 24% and 64% of trials respectively. There were no statistically significant differences in the magnitude of treatment outcomes comparing adequate versus inadequate or unclear allocation concealment, nor comparing adequate and inadequately examiner masked trials. However, a retrospective power calculation indicated 265 RCTs would be needed to demonstrate a statistically significant effect for the impact of bias on CAL as an outcome measure for a 0.5 mm exaggeration of mean difference between test and control.

CONCLUSIONS

There is insufficient evidence to support or refute the theory that the bias from improper methods of allocation concealment and examiner masking affect the magnitude of clinical outcomes in periodontology trials. The pilot data provide a baseline for sample size calculations in future research.

A systematic review of the preventive effect of oral hygiene on pneumonia and respiratory tract infection in elderly people in hospitals and nursing homes: effect estimates and methodological quality of randomized controlled trials

The objective of this study was to investigate the preventive effect of oral hygiene on pneumonia and respiratory tract infection, focusing on elderly people in hospitals and nursing homes, by systematically reviewing effect estimates and methodological quality of randomized controlled trials (RCTs) and to provide an overview of additional clinical studies in this area. Literature searches were conducted in the Medline database, the Cochrane library databases, and by hand-searching reference lists. Included publications were analyzed for intervention (or topic) studied, main conclusions, strength of evidence, and study design. RCTs were further analyzed for effect magnitudes and methodological details. Absolute risk reductions (ARRs) and numbers needed to treat (NNTs) were calculated. Fifteen publications fulfilled the inclusion criteria. There was a wide variation in the design and quality of the studies included. The RCTs revealed positive preventive effects of oral hygiene on pneumonia and respiratory tract infection in hospitalized elderly people and elderly nursing home residents, with ARRs from 6.6% to 11.7% and NNTs from 8.6 to 15.3 individuals. The non-RCT studies contributed to inconclusive evidence on the association and correlation between oral hygiene and pneumonia or respiratory tract infection in elderly people. Mechanical oral hygiene has a preventive effect on mortality from pneumonia, and non-fatal pneumonia in hospitalized elderly people and elderly nursing home residents. Approximately one in 10 cases of death from pneumonia in elderly nursing home residents may be prevented by improving oral hygiene. Future research in this area should be focused on high-quality RCTs with appropriate sample size calculations.

Optimizing search strategies to identify randomized controlled trials in MEDLINE

BACKGROUND

The Cochrane Highly Sensitive Search Strategy (HSSS), which contains three phases, is widely used to identify Randomized Controlled Trials (RCTs) in MEDLINE. Lefebvre and Clarke suggest that reviewers might consider using four revisions of the HSSS. The objective of this study is to validate these four revisions: combining the free text terms volunteer, crossover, versus, and the Medical Subject Heading CROSS-OVER STUDIES with the top two phases of the HSSS, respectively.

METHODS

We replicated the subject search for 61 Cochrane reviews. The included studies of each review that were indexed in MEDLINE were pooled together by review and then combined with the subject search and each of the four proposed search strategies, the top two phases of the HSSS, and all three phases of the HSSS. These retrievals were used to calculate the sensitivity and precision of each of the six search strategies for each review.

RESULTS

Across the 61 reviews, the search term versus combined with the top two phases of the HSSS was able to find 3 more included studies than the top two phases of the HSSS alone, or in combination with any of the other proposed search terms, but at the expense of missing 56 relevant articles that would be found if all three phases of the HSSS were used. The estimated time needed to finish a review is 1086 hours for all three phases of the HSSS, 823 hours for the strategy versus, 818 hours for the first two phases of the HSSS or any of the other three proposed strategies.

CONCLUSION

This study shows that compared to the first two phases of the HSSS, adding the term versus to the top two phases of the HSSS balances the sensitivity and precision in the reviews studied here to some extent but the differences are very small. It is well known that missing relevant studies may result in bias in systematic reviews. Reviewers need to weigh the trade-offs when selecting the search strategies for identifying RCTs in MEDLINE.

Conducting systematic reviews and creating clinical practice guidelines in dentistry

BACKGROUND

High-quality systematic reviews are the basis of valid, reliable clinical practice guidelines, or CPGs. In 1999, a Canadian collaboration of dentists embarked on the process of developing guidelines.

METHODS

The Canadian Collaboration on Clinical Practice Guidelines in Dentistry, or CCCD, is a coalition of multiple stakeholders from organized dentistry and academia whose mandate is to develop CPGs for practicing dentists. In the development of the first CPG based on a systematic review of the literature, the CCCD Methodology Resource Group (of which the authors were co-chairs) gained some valuable insights. The authors wrote this article to share their experiences and lessons learned and to offer practical advice to others who may undertake similar projects.

RESULTS

The authors identify a number of methodological issues and logistical problems and make suggestions for effective management of the review and guideline development processes.

CONCLUSIONS AND PRACTICE IMPLICATIONS

Systematic reviews and the development of CPGs require rigorous methodology, as well as input from content experts and clinicians, to ensure validity and relevance. The processes are costly and time-intensive, but the anticipated outcome is enhanced clinical decision making and improved oral health.

Orthodontic literature: an overview of the last 2 decades

The aim of this study was to explore the orthodontic literature in the most important orthodontic and other dental and medical journals from 1981 to 2000. The most commonly used medical bibliographic database, MEDLINE, was used. In addition, some journals were hand searched to estimate the error of the method. Despite some indexing inconsistencies, MEDLINE was found to be a powerful and relatively accurate tool for use in bibliometric studies. About 16,000 articles with orthodontic interest were published during this period. The number of orthodontic articles written in English rose during this period, but almost half of them (45%) were published in nonorthodontic journals. Articles in the orthodontic journals are focusing more and more on diagnosis and treatment evaluation as the need for high-quality evidence becomes obvious, while other topics, such as new techniques and new materials, are losing ground. Many high-quality studies with orthodontic interest are published in nonorthodontic journals with a high Impact Factor, remaining more or less out of reach for most orthodontists.

Randomised controlled trials and publication trends in periodontal research during 1980-2000

OBJECTIVES

To study publication trends, as well as the number and proportion of randomised controlled trials covering different areas of periodontal research (RCT-Ps).

MATERIAL AND METHODS

The study was based on Medline searches (MeSH terms) for the period 1980- 2000. The RCT-Ps (n = 675) were examined for relevance for different areas of periodontal research, journals of publication, and the countries of origin.

RESULTS

In periodontal research the annual number of publications had increased from 162 in 1980 to 440 in 2000. Moreover, clinical trials in periodontal research (CT-Ps) had increased more than 10-fold, and RCT-Ps more than 15-fold. More than 4 out of 10 RCT-Ps covered the areas 'periodontal surgery' and 'gingivitis and plaque treatment or prevention'. More than 6 out of 10 RCT-Ps in total and more than 8 out of 10 RCT-Ps about 'periodontal surgery', were published in two different journals. U.S.A was the most common country of origin of RCT-Ps, contributing to almost 4 out of 10 RCT-Ps during 1988-2000.

CONCLUSION

The annual number of RCT-Ps increased substantially during 1980-2000, and a few clinical research areas predominated. Future research should give priority to areas where clinical evidence is scarce and where high-quality RCT-Ps are most needed.