How Evidence-Based Are Publications in Clinical Ophthalmic Journals?

Recent Levels of Evidence in Otolaryngology Journals

OBJECTIVE

The development of evidence-based medicine has contributed to improved patient outcomes. This study aims to identify the trends in levels of evidence in otolaryngology journals over time, as represented by the 4 most widely circulated peer-reviewed otolaryngology journals.

METHODS

A review of all articles from 2007, 2010, 2013, 2016, and 2019, in 4 major otolaryngology journals. Data points included journal source, year of publication, country of origin, first author sex, and subspecialty category within otolaryngology. Level of evidence was determined based on the study's primary research question and was graded on a scale of 1 (strongest) to 4 (weakest) based on the Oxford Centre of Evidence-based Medicine - Levels of Evidence guideline. Comparison of levels of evidence was performed using Kruskal-Wallis analysis of variance for ordinal data.

RESULTS

About 4297 articles were identified over 12 years. The number of research articles remained consistent over the 12 years of this study. Clinical research increased from 78.6% to 85.1%. Female first authorship increased from 20.3% in 2007 to 31.0% in 2019. Of 3558 articles that constituted clinical research from 2007 to 2019, level 1 studies increased from 0.9% to 3.6%, with level 4 studies remaining stable at an overall rate of 60.3%. Randomized controlled trials remained stable at 4.6% of all studies. Systematic reviews increased from 3.2% to 8.4%.

CONCLUSION

This article provides an update on the levels of evidence to allow for an honest self-assessment of otolaryngology as a scientific field.

Randomized controlled trials in ophthalmology: a bibliometric study

Background: Randomized controlled trials (RCTs) are situated at the top of hierarchy of evidence-based medicine, where its number and quality are important in the assessment of quality of evidence in a medical field. In this study, we aim to assess the status of RCTs in Ophthalmology.

Methods: On 15 ^th of May 2019, we performed a PubMed search for randomized controlled trials published in the field of ophthalmology using relevant filters and search terms. We categorized the results into specific topics in ophthalmology according to Medical Subject Heading (MeSH) database classification system. We used Altmetric explorer to identify journals and articles with the highest number of RCTs and highest citations.

Results: We found a total of 540,427 publications in the field of ophthalmology, of which only 11,634 (2.15%) of them were RCTs. ‘Retinal diseases’ was the topic with the highest number of RCTs, followed by ‘glaucoma’ and ‘conjunctival diseases’. The trial with highest number of citations was on retinal diseases. Only around 18% of all ophthalmology RCTs are published in the top 10 ophthalmology journals, with a maximum percentage of RCTs was (5.53%) published in Ophthalmology.

Conclusion: RCTs in ophthalmology primarily concern the retina, glaucoma, and a few other sub-topics, with little focus on sclera, orbit, and the eyelids. Most of the high impact RCTs are published in non-ophthalmology journals.

Publications on Clinical Research in Otolaryngology-A Systematic Analysis of Leading Journals in 2010

Background: We wanted to asses and characterize the volume of Otolaryngology publications on clinical research, published in major journals. Methods and Material: To assess volume and study type of clinical research in Otolaryngology we performed a literature search in high impact factor journals. We included 10 high impact factor Otolaryngology journals and 20 high impact factor medical journals outside this field (2011). We extracted original publications and systematic reviews from 2010. Publications were classified according to their research question, that is therapy, diagnosis, prognosis or etiology. Results: From Otolaryngology journals (impact factor 1.8 to 2.8) we identified 694 (46%) publications on original observations and 27 (2%) systematic reviews. From selected medical journals (impact factor 6.0 to 101.8) 122 (2%) publications related to Otolaryngology, 102 (83%) were on original observations and 2 (0.04%) systematic reviews. The most common category was therapy (40%). Conclusion: Half of publications in Otolaryngology concerns clinical research, which is higher than other specialties. In medical journals outside the field of Otolaryngology, a small proportion (2%) of publications is related to Otolaryngology. Striking is that systematic reviews, which are considered high level evidence, make up for only 2% of publications. We must ensure an increase of clinical research for optimizing medical practice.

Importance and Presence of High-Quality Evidence for Clinical Decisions in Neurosurgery: International Survey of Neurosurgeons

BACKGROUND

The publication rate of neurosurgical guidelines has increased tremendously over the past decade; however, only a small proportion of clinical decisions appear to be based on high-quality evidence.

OBJECTIVE

The aim was to evaluate the evidence available within neurosurgery and its value within clinical practice according to neurosurgeons.

METHODS

A Web-based survey was sent to 2552 neurosurgeons, who were members of the European Association of Neurosurgical Societies.

RESULTS

The response rate to the survey was 6.78% (173/2552). According to 48.6% (84/173) of the respondents, neurosurgery clinical practices are based on less evidence than other medical specialties and not enough high-quality evidence is available; however, 84.4% (146/173) of the respondents believed neurosurgery is amenable to evidence. Of the respondents, 59.0% (102/173) considered the neurosurgical guidelines in their hospital to be based on high-quality evidence, most of whom considered their own treatments to be based on high-quality (level I and/or level II) data (84.3%, 86/102; significantly more than for the neurosurgeons who did not consider the hospital guidelines to be based on high-quality evidence: 55%, 12/22; P<.001). Also, more neurosurgeons with formal training believed they could understand, criticize, and interpret statistical outcomes presented in journals than those without formal training (93%, 56/60 and 68%, 57/84 respectively; P<.001).

CONCLUSIONS

According to the respondents, neurosurgery is based on high-quality evidence less often than other medical specialties. The results of the survey indicate that formal training in evidence-based medicine would enable neurosurgeons to better understand, criticize, and interpret statistical outcomes presented in journals.

Has the Objective Quality of Evidence in Imaging Papers Changed Over the Last 20 Years?

RATIONALE AND OBJECTIVES

We aimed to determine if both evidence level (EL) as well as clinical efficacy (CE) of imaging manuscripts have changed over the last 20 years.

MATERIALS AND METHODS

With our review of medical literature, Institutional Review Board approval was waived, and no informed consent was required. Using Web of Science, we determined the 10 highest impact factor imaging journals. For each journal the 10 most cited and 10 average cited papers were compared for the following years: 1994, 1998, 2002, 2006, 2010, and 2014. EL was graded using the same criteria as the Journal of Bone and Joint Surgery (Wright et al., 2003). CE was graded using the criteria of Thornbury and Fryback (1991). Statistical software R and package lme4 were used to fit mixed regression models with fixed effects for group, year, and a random effect for journal.

RESULTS

EL has improved -0.03 every year on average (P < .001). The more cited papers had better ELs (group effect = -0.23, SE 0.09, P = .011). CE is lower in top cited compared to average cited articles, although the differences were not statistically significant (group effect = -0.14, SE = 0.09, P = .16). CE level increased modestly in both groups over this 20-year time period (0.06 per year, SE = 0.007, P < .001).

CONCLUSION

Over the last 20 years, imaging journal articles have improved modestly in quality of evidence, as measured by EL and CE.

A pilot study of neurointerventional research level of evidence and collaboration

Introduction

No studies have sought to provide a quantitative or qualitative critique of research in the field of neurointerventional surgery.

Objective

To analyze recent publications from the Journal of Neurointerventional Surgery (JNIS) to test a new method for assessing research and collaboration.

Methods

We reviewed all JNIS Online First publications from 25 February 2015 to 24 February 2016. All publications—human or non-human research, systematic reviews, meta-analyses, or literature reviews—were included; editorials and commentaries were excluded. For each publication, study design, number of patients, authors, contributing centers, and study subject were recorded. Level of evidence was defined using a new scale.

Results

A total of 206 articles met inclusion criteria. Only 4% were prospective studies. Twenty-eight per cent of scientific research featured patient series of nine or less. The majority of publications were categorized as low-level evidence (91%). Forty-seven per cent involved individuals from a single center, with 87% having collaboration from three or fewer centers. International collaboration was present in 19%. While 256 institutions from 31 countries were represented, 66% were represented in only one publication.

Conclusions

We queried JNIS Online First articles from a 1-year period in a pilot study to test a new method of analyzing research quality and collaboration. The methodology appears to adequately quantify the studies into evidence tiers that emulate previously published, widely accepted scales. This may be useful for future comparison of peer-reviewed journals or for studying the quality of research being performed in different disease processes or medical specialties.

Trends in the Level of Evidence in Clinical Hand Surgery Research

BACKGROUND

The application of evidence-based medicine (EBM) to the practice of hand surgery has been limited. Production of high-quality research is an integral component of EBM. With considerable improvements in the quality evidence in both orthopedic and plastic and reconstructive surgery, it is imperative that hand surgery research emulates this trend.

METHODS

A systematic review was performed on all hand surgery articles published in 6 journals over a 20-year period. The journals included Plastic and Reconstruction Surgery, Journal of Plastic, Reconstructive and Aesthetic Surgery, Journal of Hand Surgery-European Volume, Journal of Hand Surgery-American Volume, Journal of Bone & Joint Surgery, and the Bone & Joint Journal. The level of evidence of each article was determined using the Oxford level of evidence. The quality of methodology of randomized controlled trials (RCTs) was assessed using Jadad scale. Statistical analysis involved chi-squares and Student t test (P < .05).

RESULTS

A total of 972 original hand surgery research articles were reviewed. There was a significant increase in the average level of evidence of articles published between1993 and 2013. High-quality evidence only accounted for 11.2% of evidence published, with a significant increase over the study period (P = 0.001). Quantitative evaluation of the 26 published RCTs, using Jadad scale, revealed a progressive improvement in study design from 0.3 in 1993 to 3.33 in 2013.

CONCLUSIONS

Hand surgery research has mirrored trends seen in other surgical specialties, with a significant increase in quality of evidence over time. Yet, high-quality evidence still remains infrequent.

Types and quality of physical therapy research publications: has there been a change in the past decade?

PURPOSE

To describe and compare the type and quality of evidence published in physical therapy (PT) journals during two time periods (2000-2002 vs. 2010-2012) and to explore scientific editors' opinions on changes in the types and quality of articles.

METHODS

A quantitative, longitudinal, retrospective journal review was used to categorize and assess the methodological rigour of items published in four PT journals using the Hedges Project. A quantitative, descriptive, cross-sectional survey explored the opinions of scientific editors. Percentages and frequencies of article types (as defined by the Hedges Project criteria), items passing rigour, and editor responses were calculated. Statistical significance of differences in article type and rigour between the two time periods was determined using Fisher's Exact Test.

RESULTS

There was a significant increase in original studies and review articles from 2000-2002 to 2010-2012 (p<0.001, p=0.002, respectively). The overall pass rate for rigour was 33.3% in 2000-2002 and 42.5% in 2010-2012, showing a significant increase (p=0.019). The majority of editors reported an increase in systematic reviews, qualitative designs, and randomized controlled trials and believed that quality had improved by 2010-2012.

CONCLUSION

From 2000-2002 to 2010-2012, the quality of articles published in PT journals improved and the proportion of original studies and review articles increased.

Quality and reporting of publications by Indonesian researchers: a literature survey

OBJECTIVES

To evaluate the quality of reporting of the risk of bias of the Indonesian medical research.

METHODS

Publications from PubMed and non-PubMed indexed Indonesian medical journals between January 2008 to December 2010 were assessed for risk of bias based on criterion combination from Hedges-criteria and the Oxford Center for Evidence-Based Medicine. We assessed whether the publications addressed the risk of bias adequately (quality of reporting) and whether the risk of bias criterion was fulfilled (quality of methods). The quality (both of reporting and of methods) of a study was classified as "high" if, for at least two-thirds of the criteria were adequately reported and fulfilled. It was classified as "low" when only one-third of the criteria were reported and or fulfilled.

RESULTS

Of the 1753 publications, 29% (n = 507) were original medical research. For 21% (109/507) the quality of reporting was high; for 15% (77/507) the quality of methods was high. The proportion of high quality was significantly higher among PubMed than non-PubMed, with difference between proportions: (95%CI of difference: 3 to 23).

CONCLUSION

A small proportion of Indonesian studies have high quality of reporting or methods. When international reporting guidelines are endorsed and followed, the quality of future studies may improve.

Using levels of evidence to compare clinical impact from research

OBJECTIVES

Impact of medical institutions on clinical decision-making globally might be estimated by the level of evidence of their research articles. The aim of this study was to compare levels of evidence of articles for Pakistan.

METHODS

We compared levels of evidence of articles from Pakistan, Nigeria, Japan, and the United States (U.S.).

RESULTS

Majority (73%) of articles in U.S. general medical journals were high levels (1-2), while majority (66% to 95%) in Japanese, Nigerian, Pakistani, and sub-specialty U.S. journals were lower levels (3-4) (P < 0.001). The number of articles from various regions of Pakistan did not correspond to their population or number of medical colleges/universities, mainly due to the skewing effect of one institution from Karachi which contributed 38% of all high-level articles.

CONCLUSIONS

A comparison of levels of evidence of articles across institutions might reflect relative potential of clinical impact, and might be useful for institutions, policy makers, and health research planners for priority setting.

Level of evidence of clinical spinal research and its correlation with journal impact factor

BACKGROUND

Over the past two decades, there has been a growing recognition and emphasis on the practice of evidence-based medicine (EBM). The level of evidence (LOE) is used to classify clinical studies based on their quality and design. To compare the quality of scientific journals, the impact factor (IF) is the most widely used ranking measure. However, the calculation of IF is not directly dependent on the quality or LOE of clinical articles published in a journal.

PURPOSE

The primary aim of this study was to evaluate the current LOE for clinical research in leading spinal journals and assess the relationship between LOE and IF. We hypothesized that most clinical research would provide level IV evidence, and that a positive correlation would exist between the proportion of high LOE articles and the journal IF.

STUDY DESIGN

A systematic review of all the articles in five general spinal journals was undertaken during 2010.

SAMPLE

All online articles in The Spine Journal, Spine, European Spine Journal, Journal of Neurosurgery: Spine, and Journal of Spinal Disorders and Techniques during 2010, as well as supplements were included.

OUTCOME MEASURE

The LOE for each clinical study was assessed using guidelines produced by the Oxford Centre for Evidence-Based Medicine.

METHODS

Two reviewers independently assessed all articles.

RESULTS

Overall 703 articles were suitable for LOE grading. Of these, 4.7% provided level I evidence, 23.2% level II, 12.5% level III, and 59.6% level IV. There was a significant association between LOE and type of study (p<.001); articles on therapeutic studies had the largest proportion (71.8%) of level IV evidence. There was a strong positive correlation between the proportion of level I and II evidence and the journal impact factor (ρ=0.9; 95% confidence interval 0.1 to 0.99; p=.037).

CONCLUSION

Spinal surgery journals with a higher IF contain a larger proportion of studies with high LOE, however most clinical articles provide level IV evidence of which the highest proportion are therapeutic studies. Clinicians, researchers, and journal editors should work hand in hand to enhance evidence-based practice in spinal care.

The level of evidence in two leading endodontic journals

INTRODUCTION

The successful practice of dentistry, including endodontics, relies on a wide spectrum of dental research. The quantity and quality of research evidence in endodontics have seldom been evaluated. The aim of this study was to evaluate the level of evidence in current leading endodontic journals.

MATERIALS AND METHODS

All the articles published in 2000, 2006 and 2010 in two major endodontic journals (Journal of Endodontics and International Endodontic Journal) were evaluated. These articles were classified according to the level of evidence (LOE) using Oxford Scale from 0 to 5 and type of the study.

RESULTS

Of the articles assessed, 3.2% were clinical trials, 47.8% were experimental, 5.6% were animal studies and 43.4% were of other types. Subdivisions according to LOE were 4.3% as level 1, 0.9 % level 2, 7.3% level 3, 0.4% level 4 and 3.5% level 5. Overall, 83.6% of the articles were classified as "non-evidence-based". There was a marginally significant increase in the percentage of articles with high level of evidence in recent years.

CONCLUSION

There is a substantial shortage of articles with high level of evidence in clinical endodontics. However, there was a gradual increase in the number of high LOE articles published in both journals.

Level of evidence in hand surgery

Background

Few investigations have been done to analyze the level of evidence in journals related to hand surgery, compared to other related research fields. The objective of this study was to assess the level of evidence of the clinical research papers published in the Ibero-american (RICMA), the European (JHSE) and American (JHSA) Journals of Hand Surgery.

Methods

A total of 932 clinical research papers published between 2005 and 2009 (RICMA 60, JHSE 461, and JHSA 411) were reviewed. Two independent observers classified the level of evidence based on the Oxford International Classification, 5 being the lowest level and 1 the highest level. The observed frequencies of the level of evidence for each journal were compared with the expected frequencies by a chi-square (χ ²) test for categorical variables with a significance level of 0.05.

Results

Inter-observer agreement analysis showed a Kappa of 0.617. Intra-observer agreement analysis presented a Kappa of 0.66 for the observer 1, and a Kappa of 0.751 for the observer 2. More than 80% of the papers in RICMA and JHSE and a 67.6% in the JHSA presented a level of 4. No level 1 or 2 studies were published in RICMA, compared to JHSE (0.9% level 1 and 5.0% level 2) and JHSA (8.3% level 1 and 10% level 2). The percentage of papers with level 3 published in RICMA (16.7%) was higher compared to the JHSE (11.1%) and the JHSA (14.1%). All the results were statistically significant (χ²=63.945; p<0.001).

Conclusions

The level of evidence in hand surgery is dependent on the type of journal; being the highest level evidence papers those published in the JHSA, followed by the JHSE and finally the RICMA. Knowing the status of the level of evidence published in hand surgery is the starting point to face the challenges of improving the quality of our clinical research

Level of evidence in four selected rehabilitation journals

OBJECTIVE

To investigate the methodologic quality and level of evidence of publications in major peer-reviewed general rehabilitation journals (Archives of Physical Medicine and Rehabilitation [APMR], American Journal of Physical Medicine and Rehabilitation [AJPMR], Clinical Rehabilitation [CR], and Physical Therapy [PT]).

DESIGN

Descriptive, comparative.

MAIN OUTCOME MEASURES

All the articles published in AJPMR, APMR, CR, and PT between January 2005 and December 2009 were investigated. Type of study and level of evidence were recorded for all articles. Selection and assessment of articles were based on the title and abstract by 2 independent raters.

RESULTS

The most frequently published reports were randomized controlled trials (12.7%), followed by cross-sectional studies (12.1%), case reports/case series (10.3%), validation studies (9.3%), cohort studies (8.9%), clinical trials (7.5%), case-control studies (6.8%), and other study types (32.4%). When the articles were classified according to their level of evidence, level I studies most frequently appeared in CR (29.1%), followed by PT (11.0%), APMR (10.5%), and AJPMR (7.1%). Most of the meta-analyses (10) were in APMR, and there were none in AJPMR.

CONCLUSIONS

Randomized controlled trials and meta-analyses form only a small proportion of articles published in the current rehabilitation literature. The numbers of randomized controlled trials and meta-analysis are comparable with those in other fields.

Subspecialization of the ophthalmic literature: a review of the publishing trends of the top general, clinical ophthalmic journals

PURPOSE

To investigate the publishing trends of the top general clinical ophthalmic journals and to report: (1) the proportions of articles published in terms of ophthalmic subspecialty, (2) the study design used, (3) any changes in publishing trends, and (4) any differences in the quality of study design between the subspecialties.

DESIGN

Retrospective, database review.

PARTICIPANTS

All original articles published in the top general, clinical ophthalmology journals from 2005 through 2009.

METHODS

All general, clinical ophthalmic journals were selected from the top 20 journals based on 2008 impact factor. All abstracts from original articles were reviewed, and the subject matter was recorded as belonging to 1 of the 11 ophthalmic subspecialties. After the content of the article was assigned, then the study design was recorded as one of the following: nonanalytic study, case-control or cohort study, randomized control trial, meta-analysis, laboratory science article, or systemic review.

MAIN OUTCOME MEASURES

Subspecialty of the article and the study design used.

RESULTS

Seven journals were included, and 12 426 abstracts were reviewed. Articles relating to medical retina were the most prevalent (29.1%), and those relating to strabismus were the least prevalent (2.3%). Case-control or cohort studies comprised most study designs (40.1%), with meta-analyses comprising the least (0.3%). The mean number of articles per year was 2485 (standard deviation, 125.1), remaining stable over the study period. Medical retina articles were significantly more common in 2009 than in 2005 (chi-square, 11.2; P = 0.0008), whereas the proportion of oculoplastic articles was significantly reduced (chi-square, 16.9; P<0.0001). Cataract and refractive surgery had the highest proportions of articles using the higher forms of study design (7.8%), and oculoplastics had the highest proportion of nonanalytic studies (64.5%).

CONCLUSIONS

There are great differences across the specialty of ophthalmology in the subject matter of published literature, probably driven by recent advances in treatments. Medical retina is the subspecialty that is most represented in the literature, with strabismus being the least represented. Cataract and refractive surgery articles have the greatest proportion of higher-quality research strategies.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Potential bias in ophthalmic pharmaceutical clinical trials

To make clinicians aware of potential sources of error in ophthalmic pharmaceutical clinical trials that can lead to erroneous interpretation of results, a critical review of the study design of various pharmaceutical ophthalmic clinical trials was completed. Discrepancies as a result of study shortcomings may explain observed differences between reported ophthalmic trial data and observed clinical results.

Quality of reporting of key methodological items of randomized controlled trials in clinical ophthalmic journals

PURPOSE

To evaluate the reporting quality of key methodological items in randomized controlled trials (RCTs) in four general clinical ophthalmology journals.

METHODS

The reporting of 11 key methodological items in RCTs published in American Journal of Ophthalmology, Archives of Ophthalmology, British Journal of Ophthalmology and Ophthalmology in the year 2005 was assessed.

RESULTS

Sixty-seven eligible RCTs were assessed and the mean number of items reported was 6.3 per RCT. No significant difference in the mean number of items reported was found between the four journals (P=0.20). The most frequently reported item was ethics approval and informed consent (97.0%), followed by masking status (85.1%), description of withdrawals (76.1%), adverse events (73.1%), and intention-to-treat analysis (71.6%). Details on sequence generation, randomization restriction, allocation concealment, allocation implementation, patient flow diagrams, and sample size calculation were reported in <50% of the RCTs assessed. Both sample size and page length of the RCTs correlated with the number of methodological items reported (P=0.024 and P=0.008, respectively).

CONCLUSIONS

Similar to other specialties, rooms for improvement exist in the reporting of key methodological items of RCTs in clinical ophthalmic journals. Stricter adoption of the CONSORT statement might enhance the reporting quality of RCTs in ophthalmic journals.

Levels of Evidence in the Urological Literature

PURPOSE

The concept of levels of evidence is one of the guiding principles of evidence based clinical practice. It is based on the understanding that certain study designs are more likely to be affected by bias than others. We provide an assessment of the type and levels of evidence found in the urological literature.

MATERIALS AND METHODS

Three reviewers rated a random sample of 600 articles published in 4 major urology journals, including 300 each in 2000 and 2005. The level of evidence rating system was adapted from the Center of Evidence Based Medicine. Sample size was estimated to detect a relative increase in the proportion of studies that provided a high level of evidence (I and II combined) from 0.2 to 0.3 with 80% power.

RESULTS

Of the 600 studies reviewed 60.3% addressed questions of therapy or prevention, 11.5% addressed etiology/harm, 11.3% addressed prognosis and 9.2% addressed diagnosis. The levels of evidence provided by these studies from I to IV were 5.3%, 10.3%, 9.8% and 74.5%, respectively. A high level of evidence was provided by 16.0% of studies in 2000 and by 15.3% in 2005 (p = 0.911).

CONCLUSIONS

This study suggests that a majority of studies in the urological literature provide low levels of evidence that may not be well suited to guide clinical decision making. We propose that editors of leading urology journals should promote awareness for this guiding principle of evidence based clinical practice by providing a level of evidence designation with each published study.

Redundant publication of clinical trials on herpetic keratitis

PURPOSE

To examine reported clinical trials on herpes simplex virus epithelial keratitis as a case study for the configuration and possible motives of overlapping publications in the ophthalmic literature.

DESIGN

Cross-sectional bibliometric survey.

METHODS

One hundred and forty-four reports of 98 randomized clinical trials that formed the framework for a systematic review on dendritic and geographic keratitis were assembled by electronic and manual searching of biomedical journals and transactions, excluding meeting abstracts. Overlapping reports were identified by comparing methods and results. Main articles giving the most detailed results among overlapping reports were contrasted with trial reports without duplication. Annual citation rates since publication were estimated from the number of times each report was cited by subsequent scientific articles indexed in an online citation database.

RESULTS

Sixty-one articles were published once, while 83 articles overlapped in 23 clusters, of which 14 (50%) lacked bibliographic cross-reference. Of 55 secondary reports, 34 (62%) had a smaller sample size than their corresponding main report. Secondary articles were less likely to appear in an ophthalmological publication than main reports (P < .001) and were later cited less often (P = .01). Compared to trial reports published once, main articles with an overlapping report had a significantly higher citation rate (P = .04).

CONCLUSION

Overlapping publications of therapeutic trials on herpetic keratitis often had undisclosed or fragmentary interconnections. Subsequent authors cited articles having an overlapping report more often than trials published once.

Biphasic Insulin Aspart in Type??2??Diabetes Mellitus

The efficacy benefits of biphasic insulin aspart formulation (BIAsp 30) in patients with diabetes mellitus have been reported in several studies. BIAsp 30 has been shown to be more effective in terms of glycaemic control than standard biphasic human insulin 30 (BHI 30). In addition to gauging the treatment in terms of clinical evidence of benefits provided, it is also important to evaluate the strength of the evidence supporting the therapeutic improvements offered by BIAsp 30. In this paper, we evaluated the strength of the available data that relate to the use of BIAsp 30 in the treatment of patients with type 2 diabetes based on a comprehensive literature review. Selected publications that provided relevant data were obtained via a literature search and from the manufacturer, Novo Nordisk. These were graded in terms of the strength of the evidence they provided using the Oxford Centre for Evidence-Based Medicine (CEBM) system in the following categories: (i) twice-daily use versus basal insulin; (ii) twice-daily use versus other treatments; (iii) once-daily use; (iv) thrice-daily use; (v) use in combination with thiazolidinediones; and (vi) use in comparison with BHI 30. A total of 30 publications for BIAsp 30 were identified and graded. For the majority of categories (four out of six), the evidence supporting the use of BIAsp 30 was given an overall CEBM grade of A (highest quality); evidence supporting clinical efficacy in the other two categories (twice-daily use versus basal insulin and thrice-daily BIAsp 30 administration) was graded B. In most of the studies examined, the efficacy of BIAsp 30 was evaluated in terms of glycaemic control (glycosylated haemoglobin [HbA(1c)] reduction, proportion of patients achieving HbA(1c) target of <6.5% or <7%, fasting blood glucose, blood glucose profile and/or prandial and postprandial glucose increments). In some studies, efficacy was further evaluated using plasma insulin and glucose infusion rates, plasma C-peptide levels, mean serum fructosamine levels, postprandial hyperlipidaemia, overall well-being, treatment satisfaction and quality of life. Safety was evaluated using physical and laboratory investigations and assessment of incidence of adverse events, including, in many of the studies reviewed, specific evaluation of those events known to be associated with antidiabetic treatment, hypoglycaemia and weight gain. Strong evidence was provided for better glycaemic control with BIAsp 30 without increases in the incidence of major hypoglycaemia or nocturnal hypoglycaemic episodes. Overall, weight gain with BIAsp 30 was minimal and not significantly greater than with basal insulin or BHI 30. Thus, we can confirm that the reported efficacy and tolerability of BIAsp 30 in the treatment of diabetes based on a variety of clinical endpoints is supported by a good body of evidence relating to its use in different dosage regimens and in comparison with other insulin treatment regimens.