Research Methodology and Analytic Techniques Used in the Journal Obstetrics & Gynecology

Clinical research and diagnostic efficacy studies in the oral and maxillofacial radiology literature: 1996-2005

OBJECTIVES

The aim of this study was to determine the level of evidence that is published in the oral and maxillofacial radiology (OMR) literature.

METHODS

OMR papers published in Dentomaxillofacial Radiology and Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology between 1996 and 2005 were classified using epidemiological study design and diagnostic efficacy hierarchies. The country of origin and number of authors were noted.

RESULTS

Of the 725 articles, 384 could be classified with the epidemiological study design hierarchy: 155 (40%) case reports/series and 207 (54%) cross-sectional studies. The distribution of study designs was not statistically significant across time (Fisher's exact test, P = 0.06) or regions (P = 0.89). The diagnostic efficacy hierarchy was applicable to 246 articles: 71 (29%) technical efficacy and 166 (67%) diagnostic accuracy studies. The distribution of efficacy levels was not statistically significant across time (P = 0.22) but was significant across regions (P < 0.01). Authors from Japan produced 26% of the papers with a mean ± standard deviation of 5.78 ± 1.98 authors per paper (APP); American authors, 23% (3.78 ± 1.72 APP); and all others, 51% (3.76 ± 1.51 APP).

CONCLUSION

The OMR literature consisted mostly of case reports/series, cross-sectional, technical efficacy and diagnostic accuracy studies. Such studies do not provide strong evidence for clinical decision making nor do they address the impact of diagnostic imaging on patient care. More studies at the higher end of the study design and efficacy hierarchies are needed in order to make wise choices regarding clinical decisions and resource allocations.

Learning outcomes from a biomedical research course for second year osteopathic medical students

Background

A ubiquitous dilemma in medical education continues to be whether and how to integrate research competencies into the predoctoral curriculum. Understanding research concepts is imbedded in the six core competencies for physicians, but predoctoral medical education typically does not explicitly include research education. In an effort to quickly report academic research findings to the field, this is the second in a series of articles reporting the outcomes of a research education initiative at one college of osteopathic medicine. The first article described the competency model and reported baseline performance in applied understanding of targeted research concepts. This second article reports on the learning outcomes from the inaugural year of a course in basic biomedical research concepts.

Methods

This course consisted of 24 total hours of classroom lectures augmented with web-based materials using Blackboard Vista, faculty moderated student presentations of research articles, and quizzes. To measure changes in applied understanding of targeted research concepts in the inaugural year of the course, we administered a pretest and a posttest to second year students who took the course and to first year students who took an informatics course in the same academic year.

Results

We analyzed 154 matched pretests and posttests representing 56% of the 273 first and second year students. On average, the first year (53) and second year students (101) did not differ in their mean pretest scores. At posttest the second year students showed significant improvement in their applied understanding of the concepts, whereas the first year students' mean posttest score was lower than their mean pretest score.

Conclusions

This biomedical research course appears to have increased the second year students' applied understanding of the targeted biomedical research concepts. This assessment of learning outcomes has facilitated the quality improvement process for the course, and improved our understanding of how to measure the benefits of research education for medical students. Some of the course content and methods, and the outcome measures may need to be approached differently in the future to more effectively lay the foundation for osteopathic medical students to utilize these concepts in the clinical setting.

The importance of case reports in advancing scientific knowledge of rare diseases

Case reports are defined as the scientific documentation of a single clinical observation and have a time-honored and rich tradition in medicine and scientific publication. Case reports represent a relevant, timely, and important study design in advancing medical scientific knowledge especially of rare diseases. While there are clear limitations to the methodology of case studies in determination of treatment and establishment of new tests, the observation of a single patient can add to our understanding of etiology, pathogenesis, natural history, and treatment of particularly rare diseases, and to the training of potential junior investigators. In recent years this class of scientific publication has come under scrutiny and disfavor among some in the medical scientific publication community and case studies are frequently relegated to the lowest rung of the hierarchy of study design. In this chapter the author will review and summarize the debate around the scientific publication of case reports in the context of the study of rare diseases and will present a taxonomy that ideally will encourage further dialogue on the topic. Future research on the importance of case reports in advancing knowledge of rare diseases is recommended.

Methodology and analytic techniques used in clinical research: associations with journal impact factor

OBJECTIVE

To describe research methodology and statistical reporting of published articles in high-impact-factor general medical journals compared with moderate-impact-factor obstetrics and gynecology journals.

METHODS

A cross-sectional analysis was performed on 371 articles published from January to June 2006 in six journals (high-impact-factor group: Journal of the American Medical Association, The Lancet, the New England Journal of Medicine; moderate-impact-factor group-American Journal of Obstetrics & Gynecology, British Journal of Obstetrics and Gynaecology, and Obstetrics & Gynecology). Articles were classified by level of evidence. Data abstracted from each article included number of authors, clearly stated hypothesis, sample size/power calculations, statistical measures, and use of regression analysis. Univariable analyses were performed to evaluate differences between the high-impact-factor and moderate-impact-factor groups.

RESULTS

The majority of published reports were observational studies (50%), followed by randomized controlled trials ([RCTs] 24%), case reports (14%), systematic reviews (6%), case series (1%), and other study types (4%). Within the high-impact-factor group, 35% were RCTs compared with 12% in the moderate-impact-factor group (relative risk 2.9, 95% confidence interval 1.9-4.4). Recommended statistical reporting (eg, point estimates with measures of precision) was more common in the high-impact-factor group (P<.005).

CONCLUSION

The proportion of RCTs published among the high-impact-factor group was three times that of the moderate group. Efforts to provide the highest level of evidence and statistical reporting have the potential to improve the quality of reports in the medical literature available for clinical decision making.

LEVEL OF EVIDENCE

III.

Risk factors for stillbirth in developing countries: a systematic review of the literature

OBJECTIVE

To identify risk factors for stillbirth in developing countries and to measure their impact by calculating the population attributable fraction (PAF) for each risk factor.

STUDY DESIGN

Systematic review of published studies on risk factors for stillbirth within 3 broadly defined categories: infections, other clinical conditions, and context-dependent conditions such as socioeconomic status, maternal literacy, and receipt of antenatal care. Where statistically significant associations were found between a risk factor and occurrence of stillbirth, the PAF (the proportion of cases occurring in the total population that would be avoided if the exposure was removed) was calculated.

RESULTS

A total of 33 studies, conducted in 31 developing countries, were included in the review. The definition of stillbirth varied widely in these studies. Risk factors for stillbirth having a PAF higher than 50% were maternal syphilis, chorioamnionitis, maternal malnutrition, lack of antenatal care, and maternal socioeconomic disadvantage.

CONCLUSIONS

Maternal syphilis prevention, screening and treatment together with other interventions targeting universal use of antenatal care (that includes screening for syphilis) and improving the socioeconomic conditions including nutritional status of the mother, could effectively contribute towards reducing the unacceptably high burden due to stillbirth in developing countries.

Significance of case reports in the advancement of medical scientific knowledge

In an Editorial Comment in 2006 Carey summarized the issues surrounding the publication of case reports in the current medical literature. In this present study, three questions about case reports are posed by the author: Do journals still publish single case reports? What do medical journals call these reports? And how should we classify reports of single clinical observations? The author examined the table of contents of 25 prominent journals and addressed the question as to whether these selected periodicals published case reports. The analysis showed that 32% of reviewed journals published case reports and 32% did not, while the remainder of journals published this class of papers but in a modified fashion and not regularly. Journals varied in what term they use to describe case reports. The author proposed a classification system for case reports in the human genetics literature. More dialogue and research is needed to examine the role of case reports in the medical scientific literature.

An observational examination of the literature in diagnostic anatomic pathology

Original research published in the medical literature confronts the reader with three very basic and closely linked questions--are the authors' conclusions true in the contextual setting in which the work was performed (internally valid); if so, are the conclusions also applicable in other practice settings (externally valid); and, if the conclusions of the study are bona fide, do they represent an important contribution to medical practice or are they true-but-insignificant? Most publications attempt to convince readers that the researchers' conclusions are both internally valid and important, and occasionally papers also directly address external validity. Developing standardized methods to facilitate the prospective determination of research importance would be useful to both journals and their readers, but has proven difficult. In contrast, the evidence-based medicine (EBM) movement has had more success with understanding and codifying factors thought to promote research validity. Of the many variables that can influence research validity, research design is the one that has received the most attention. The present paper reviews the contributions of EBM to understanding research validity, looking for areas where EBM's body of knowledge is applicable to the anatomic pathology (AP) literature. As part of this project, the authors performed a pilot observational analysis of a representative sample of the current pertinent literature on diagnostic tissue pathology. The results of that review showed that most of the latter publications employ one of the four categories of "observational" research design that have been delineated by the EBM movement, and that the most common of these observational designs is a "cross-sectional" comparison. Pathologists do not presently use the "experimental" research designs so admired by advocates of EBM. Slightly > 50% of AP observational studies employed statistical evaluations to support their final conclusions. Comparison of the current AP literature with a selected group of papers published in 1977 shows a discernible change over that period that has affected not just technological procedures, but also research design and use of statistics. Although we feel that advocates of EBM deserve credit for bringing attention to the close link between research design and research validity, much of the EBM effort has centered on refining "experimental" methodology, and the complexities of observational research have often been treated in an inappropriately dismissive manner. For advocates of EBM, an observational study is what you are relegated to as a second choice when you are unable to do an experimental study. The latter viewpoint may be true for evaluating new chemotherapeutic agents, but is unacceptable to pathologists, whose research advances are currently completely dependent on well-conducted observational research. Rather than succumb to randomization envy and accept EBM's assertion that observational research is second best, the challenge to AP is to develop and adhere to standards for observational research that will allow our patients to benefit from the full potential of this time tested approach to developing valid insights into disease.