Review articles meta-analyses

The number of clinical communications published per year has increased to staggering proportions. Matthews (2006) noted that there are currently on the order of20,000 biomedical journals that publish on the order of two million articles a year. This makes it extremely difficult for a clinician who would like to research a particular topic to locate all of the relevant articles. Accordingly, two kinds of review papers can be very helpful. The first is narrative reviews. These collate, compare, discuss, and summarize the current state of knowledge (Matthews, 2006). Narrative reviews are descriptive in nature. The second kind of review incorporates meta-analysis. These reviews are quantitative in nature. 

It was noted in the previous section that studies with positive findings are more likely to be published in English language journals. The first criterion in the bulleted list just presented therefore gives articles with positive findings a better chance of capture in the computer search process and, therefore, inclusion in the systematic review or meta-analysis. The fact that studies with positive results are more likely to be published in more than one journal (noted in the previous section) also gives these articles a better chance of capture in the computer search process and inclusion in the systematic review or meta-analysis. 

The article that follows is a controversial one. It reaches a controversial conclusion - that much of the therapeutic benefit of antidepressant medications actually derives from placebo responding. The article reaches this conclusion by utilizing a controversial statistical approach - meta-analysis. And it employs meta-analysis controversially - by meta-analysing studies that are very heterogeneous in subject selection criteria, treatments employed, and statistical methods used. Nonetheless, we have chosen to publish the article. We have done so because a number of the colleagues who originally reviewed the manuscript believed it had considerable merit, even while they recognized the clearly contentious conclusions it... 

Traditionally, one did a review of those studies writing a narrative about them and drawing conclusions based on the subjective evaluation of this information by the reviewer. A different way to write review articles, named meta-analysis, was introduced into clinical medicine by Chalmers. It has been defined as a systematic review of studies that uses quantitative statistical procedures to combine, synthesize, and integrate information across these studies . What this methodology does is take a group of... 

We believe the file drawer issue is less of a problem in meta-analysis than in the narrative review, which often lists only those publications that support a particular conclusion. Too often, narrative reviewers emphasize the results of other positive reviews. Thus, the reference list gives a false impression of more studies than were actually done, because duplicate publications and review articles are quoted as if they were independent studies. Other problems include ... 

Two kinds of publication can help make sense of a set of differing, and even conflicting, conclusions from a collection of articles on a given topic. One is a systematic review. The strategy in this case is to describe, summarize, and collate the studies in a nonquantitative manner to look for emerging patterns or pictures of evidence. A quantitative approach is provided by the technique of meta-analysis. The results of the different studies are combined according to certain rules, and an overall test statistic is provided. The interpretation of this test statistic leads to the overall message of the meta-analysis. 

The British medical journal, Lancet, recently published a meta-analysis (systemic review of research articles) that looked at the long-term effects of severely depressed patients taking the SSRI Zoloft (sertraline). Most patients not only felt much better after short-term antidepressant therapy but were able to function better, a surprising result considering the seriousness of the illness. A majority of those polled were much improved in just six to twelve weeks however, they tended to lose their psychosocial gains after discontinuing their medication. Overall, 70 percent of patients who discontinued SSRIs relapsed, compared to 40 percent of those who... 

Systematic review The application of strategies that limit bias in the assembly, critical appraisal and synthesis of all relevant studies on a specific topic. Systematic reviews focus on peer-reviewed publications about a specific health problem and use rigorous, standardized methods to select and assess articles. A systematic review differs from a meta-analysis in not including a quantitative summary of the results (Porta 2008). 

A systematic review is presented which was prepared for evidence-based recommendations on the use of vitamin D analogoues, and their combination with topical steroids in psoriasis [86. To assess efficacy across studies, two predefined criteria to account for the munerous end points found in the literature, treatment success corresponding to 90% improvement in severity, and satisfactory response corresponding to 75% improvement, were used. Then a meta-analysis was conducted comparing the efficacy of vitamin D analogoues plus topical steroids (VDS) vs vitamin D analogoues alone (VD). From the results, which were collected from 51 articles, the application duration varied between three and 52 weeks across studies. 

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