A Critically Appraised Topic (CAT) is a form of summarised evidence that tries to present an answer to a specified clinical question. A CAT is different to a systematic review or meta-analysis as the intention is not to systematically seek out all the evidence on a topic, but to look for the best available evidence and quickly come up with an answer. A CAT might be appropriate where there was no national guidance, but is not robust on its own to override existing national guidance.<\/p>\n\n\n\n
A CAT starts with a well-defined clinical question that is relevant, well-structured and answerable. This then needs to be translated into a search question using a framework such as PICO (Patient or problem, Intervention or exposure, Comparison or control, Outcome(s)).<\/p>\n\n\n\n
For a therapy questions, PICO would consist of the patient's disease or condition, a therapeutic intervention (for example a drug, surgical intervention, or medical advice). The comparison might be standard care, another intervention, or a placebo, and the outcome might be, for example, reduced mortality rate, complications, or disease recurrence.<\/p>\n\n\n\n
The P (Patient or problem) may also include information about the population group (for example, older people, or women).<\/p>\n\n\n\n
For example, the question \u2018In a patient with acute bronchitis, do antibiotics reduce sputum production?\u2019 could be put into a PICO framework as:<\/p>\n\n\n\n
The PICO framework aids searching in databases, by allowing you to search for each concept separately using thesaurus and free-text terms to cover synonyms and variant spellings, and then combine the searches together to find research that covers all the concepts.<\/p>\n\n\n\n
Since most CATs are related to therapy questions, the most appropriate study design would be an existing systematic review<\/a>, or randomised controlled trials (RCTs)<\/a> and these could be found in databases such as the Cochrane Library<\/a>, Medline<\/a>, EMBASE<\/a> and CINAHL<\/a>. Search filters are available to help limit the search to systematic reviews or RCTs.<\/p>\n\n\n\n Library staff are happy to either provide training and assistance<\/a> on how to search these databases, or can carry out evidence searches<\/a> on your behalf.<\/p>\n\n\n\n