Meta-analysis and structured literature review in radiology

Methods to systematically review and meta-analyse observational studies: a systematic scoping review of recommendations

Background

Systematic reviews and meta-analyses of observational studies are frequently performed, but no widely accepted guidance is available at present. We performed a systematic scoping review of published methodological recommendations on how to systematically review and meta-analyse observational studies.

Methods

We searched online databases and websites and contacted experts in the field to locate potentially eligible articles. We included articles that provided any type of recommendation on how to conduct systematic reviews and meta-analyses of observational studies. We extracted and summarised recommendations on pre-defined key items: protocol development, research question, search strategy, study eligibility, data extraction, dealing with different study designs, risk of bias assessment, publication bias, heterogeneity, statistical analysis. We summarised recommendations by key item, identifying areas of agreement and disagreement as well as areas where recommendations were missing or scarce.

Results

The searches identified 2461 articles of which 93 were eligible. Many recommendations for reviews and meta-analyses of observational studies were transferred from guidance developed for reviews and meta-analyses of RCTs. Although there was substantial agreement in some methodological areas there was also considerable disagreement on how evidence synthesis of observational studies should be conducted. Conflicting recommendations were seen on topics such as the inclusion of different study designs in systematic reviews and meta-analyses, the use of quality scales to assess the risk of bias, and the choice of model (e.g. fixed vs. random effects) for meta-analysis.

Conclusion

There is a need for sound methodological guidance on how to conduct systematic reviews and meta-analyses of observational studies, which critically considers areas in which there are conflicting recommendations.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0495-9) contains supplementary material, which is available to authorized users.

A comment on experimental results of fingerprint comparison validity and reliability: A review and critical analysis

We respond to the article "Experimental results of fingerprint comparison validity and reliability: A review and critical analysis" by Ralph and Lyn Haber which offers (a) a one-sided criticism of the state of affairs in latent print examination, (b) lack of original data supporting that their suggested approach, and (c) a host of incorrect statements, inaccuracies, or obscure interpretations of the existing data.

Optimizing the role of imaging in appendicitis

Acute appendicitis is the most common acute abdominal condition that requires surgical intervention in childhood. From the diagnostic performance perspective, computed tomography (CT) has a significantly higher sensitivity than does ultrasound (US) for diagnosing appendicitis in children; from the safety perspective, however, one should consider the radiation associated with CT, especially in children. There is strong evidence supporting improved patient outcomes in children with suspected acute appendicitis who undergo CT scanning. Nevertheless, we should keep in mind that for a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients, based on probabilistic models designed with data from atomic bomb survivors. An integrated clinical-imaging approach, applying clinical scores that are able to predict which children with acute abdominal pain do or do not have a high probability of presenting with appendicitis may improve the effectiveness of the imaging diagnosis of appendicitis at the hospital level. Such an approach could avoid exposure of children who at low risk for appendicitis to unnecessary diagnostic tests and eventually, to radiation.

Evidence-based radiology and the ACR Appropriateness Criteria

The ACR Appropriateness Criteria are an important effort aimed at establishing when imaging should be used in medicine. However, substantial improvements in the Appropriateness Criteria are necessary for them to meet current standards for evidence-based guidelines. In this article, we provide concrete suggestions for improving the evidence basis of the Appropriateness Criteria.

Deficits in facial affect recognition among antisocial populations: a meta-analysis

Individuals with disorders marked by antisocial behavior frequently show deficits in recognizing displays of facial affect. Antisociality may be associated with specific deficits in identifying fearful expressions, which would implicate dysfunction in neural structures that subserve fearful expression processing. A meta-analysis of 20 studies was conducted to assess: (a) if antisocial populations show any consistent deficits in recognizing six emotional expressions; (b) beyond any generalized impairment, whether specific fear recognition deficits are apparent; and (c) if deficits in fear recognition are a function of task difficulty. Results show a robust link between antisocial behavior and specific deficits in recognizing fearful expressions. This impairment cannot be attributed solely to task difficulty. These results suggest dysfunction among antisocial individuals in specified neural substrates, namely the amygdala, involved in processing fearful facial affect.