7 research outputs found
How does study quality affect the results of a diagnostic meta-analysis?
Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited
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Conceptualising paranoia in ASD: A systematic review and development of a theoretical framework
Paranoia, unfounded ideation that others deliberately intend harm, has predominately been studied in schizophrenia. Increasingly, it is recognised that there is a spectrum of severity of excessive mistrust across the general population. Relatively little is known about paranoia in individuals with autism spectrum disorders (ASD), but rates could be expected to be higher given both difficulties in understanding othersâ mental states and frequent experiences of negative social interactions. A systematic search of English-language peer-reviewed publications was undertaken to synthesise empirical research about paranoia in ASD. Seven studies, comprising a total of 180 ASD participants, met the inclusion criteria. All the studies were cross-sectional, thereby limiting causal interpretations. Individuals with ASD were consistently found to have higher levels of paranoia compared to non-clinical controls, and lower levels than individuals with current psychotic experiences manifesting in the context of schizophrenia. Furthermore, the initial evidence indicates that paranoia in ASD may be linked with theory of mind performance, negative affect, and jumping to conclusions, but not to attributional style. As in typically-developing populations, causal and maintaining mechanisms for paranoia in ASD, against a background of genetic and environmental risk, most likely include cognitive and affective processes interacting with social factors. We hypothesise, however, that core ASD characteristics and associated neurocognitive impairments also serve to precipitate and perpetuate paranoia. A framework to guide further investigation is outlined