Methodology and Analytic Techniques Used in Clinical Research

Abstract

Objective To describe research methodology and statistical reporting of published articles in high impact factor, general medical journals compared to moderate impact factor obstetric and gynecology journals. Methods A cross-sectional analysis was performed on 371 articles published from January to June 2006, in 6 journals (high impact factor group—Journal of the American Medical Association, Lancet, the New England Journal of Medicine; moderate impact factor group—American Journal of Obstetrics and Gynecology, British Journal of Obstetrics and Gynecology, 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 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 factor impact group, 35% were RCTs compared to 12% in the moderate impact group (RR 2.9, 95% CI 1.9-4.4). Recommended statistical reporting (eg point estimates with measures of precision) was more common in the high impact group (P<0.005). Conclusions The proportion of RCTs published among the high impact factor group was 3 times that of the moderate group. Efforts to provide the highest level of evidence and statistical reporting have potential to improve the quality of reports in the medical literature available for clinical decision making.

Methodological Reporting of Randomized Clinical Trials in Respiratory Research in 2010

“…4 The present study found a significant association between RCT quality and a high impact factor, as did Bausch et al 8 Kuroki et al found that the proportion of highquality RCTs in high-impact-factor journals was nearly 3 times that in journals with moderate impact factor. 18 In the present study we found that the proportion of highquality RCTs in the high-impact-factor journals was nearly 1.5 times that in the journals with impact factor Ͻ 5. There are several potential explanations.…”

“…Second, the editing criteria of the editors, reviewers, and statistical consultants may be stricter. 18 The trials in the general medical journals, which have higher impact factors, had better methods than those in the respiratory journals. The overall trial registration rate was 64%, and trial registration affected the adequacy of allocation, allocation concealment, and double-blinding.…”

Prevalence of randomised controlled trials in Japanese cardiovascular journals: a descriptive study

“…In earlier reports, Hayashino and colleagues demonstrated that RCTs accounted for 2.1% of all research articles from Japan published in the top 10 cardiovascular journals overseas 9. Kuroki and colleagues reported that the proportion of RCTs among published articles in the gynaecology field was 35% in high impact factor journals, such as the New England Journal of Medicine , the Lancet , and the Journal of the American Medical Association , and 12% in journals with a moderate impact factor, similar to that of Japanese cardiovascular journals 10. This study only assessed the recent 10-year trends in the proportion of RCTs published in Japanese cardiovascular journals, and further continuous observation is needed to evaluate whether the proportion of RCTs in the cardiovascular field will increase or not.…”

Deficiencies of effectiveness of intervention studies in veterinary medicine: a cross-sectional survey of ten leading veterinary and medical journals

“…Nonetheless, the present research study focused on a selected group of leading general journals. In 2006 the proportion of RCTs published among JAMA, Lancet and NEJM was almost 3 times greater than obstetric and gynecology journals (Kuroki, Allsworth & Peipert, 2009). In addition, trials published in general medical journals had higher quality scores than those in specialist journals .…”