Cochrane Methods Groups, including Cochrane Prognosis (Prognosis Methods Group - PMG), were established to develop methodology and advise Cochrane on how the validity and precision of systematic reviews can be improved.
What is prognosis research? Prognosis research provides information about the long-term health and well-being of individuals with specific diseases or conditions. Prognosis studies can provide information on the likelihood of a particular outcome or disease recurrence; they can identify target groups for treatment, or suggest intervention strategies to modify factors associated with poor outcomes. Such information is required for health care decision-making and is not always available from clinical trials. Prognostic information may also inform diagnosis. Clinical decision models or tools that help clinicians make decisions following diagnostic testing require information about prognosis before thresholds for investigation or treatment can be calculated. Also, clinical course (i.e. prognosis) may be used to validate a diagnostic test in the absence of a 'gold standard' or reference test. Prognosis studies help to separate different forms of diseases and separate different diseases which previously appeared as one disease.
Individual prognosis studies often present inconsistent conclusions. Systematic review methods are increasingly being used in many topic areas to synthesize prognosis study findings. However, application of systematic review methods in the area of prognosis is in its infancy. Although basic principles to reduce bias and random error are similar to those used for intervention reviews, there are several challenges unique to systematic reviews of prognosis: lack of clarity in the indexing of these studies for bibliographic searches; low quality of primary studies; poor reporting; and difficulties in combining results across different research designs, analyses, and presentations of results.
What is its role in evidence review? Prognostic information is important for clinicians, health service providers and consumers. Prognosis systematic reviews will help provide best evidence for healthcare decision-making relevant to diagnosis, therapy and service delivery. The Prognosis Methods Group has two primary roles:
- Work with existing Cochrane entities, including Methods Groups to ensure the best use of prognostic evidence in Cochrane reviews
- Conduct research to advance the methods of prognosis reviews and other types of reviews, where similar methods apply.
Cochrane is an international not-for-profit organisation, providing up-to-date information about the effects of health care. We produce the Cochrane Database of Systematic Reviews, part of The Cochrane Library, the definitive resource for evidence-based health care.