Nonpurulent cellulitis is an acute bacterial infection of the dermal and subdermal tissues that is not associated with purulent drainage, discharge or abscess. The objectives of this systematic review and meta-analysis were to identify and appraise all controlled observational studies that have examined risk factors for the development of nonpurulent cellulitis of the leg (NPLC). A systematic literature search of electronic databases and grey literature sources was performed in July 2015. The Newcastle-Ottawa Scale (NOS) was used to assess methodological quality of included studies. Of 3059 potentially eligible studies retrieved and screened, six case-control studies were included. An increased risk of developing NPLC was associated with previous cellulitis [odds ratio (OR) 40·3, 95% confidence interval (CI) 22·6-72·0], wound (OR 19·1, 95% CI 9·1-40·0), current leg ulcers (OR 13·7, 95% CI 7·9-23·6), lymphoedema/chronic leg oedema (OR 6·8, 95% CI 3·5-13·3), excoriating skin diseases (OR 4·4, 95% CI 2·7-7·1), tinea pedis (OR 3·2, 95% CI 1·9-5·3) and body mass index > 30 kg m (OR 2·4, 95% CI 1·4-4·0). Diabetes, smoking and alcohol consumption were not associated with NPLC. Although diabetics may have been underrepresented in the included studies, local risk factors appear to play a more significant role in the development of NPLC than do systemic risk factors. Clinicians should consider the treatment of modifiable risk factors including leg oedema, wounds, ulcers, areas of skin breakdown and toe-web intertrigo while administering antibiotic treatment for NPLC.
BackgroundAdvances in cognitive load theory have led to greater understanding of how we process verbal and visual material during learning, but the evidence base with regard to the use of images within written assessments is still sparse. This study examines whether the inclusion of images within the stimulus format of multiple choice questions (MCQs) has a predictable or consistent influence on psychometric item properties, such as difficulty or discrimination.MethodsItem analysis data from three consecutive years of histology multiple choice examinations were included in this study. All items were reviewed and categorised according to whether their stem, or stimulus format, was purely textual or included an associated image.ResultsA total of 195 MCQs were identified for inclusion and analysed using classical test theory; 95 used text alone and 100 included an image within the question stem. The number of students per examination ranged from 277 to 347, with a total of 60,850 student-question interactions. We initially examined whether the inclusion of an image within the item stem altered the item difficulty using Mann–Whitney U. The median item difficulty for images with purely textual stems was 0.77, while that for items incorporating an appropriate image was 0.80; this difference was not significant (0.77 vs. 0.80; p = 0.862, Mann–Whitney-U = 4818.5). Mean values showed that the Item Discrimination Index appeared unaffected by the inclusion of an image within the stem, and Item point biserial correlation also showed no difference in means between these two groups (Independent samples t-test; 2-tailed).ConclusionWe demonstrate that the addition of illustrations within undergraduate histology Multiple Choice Question stems has no overall influence on item difficulty, or measures of item discrimination. We conclude that the use of images in this context is statistically uncritical, and suggest that their inclusion within item stems should be based upon the principles of constructive alignment. However, further research with respect to the effect of images within item stems on cognitive processing, particularly with regard to image complexity or type, would enable the development of more informed guidelines for their use.
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