The increasing need for systematic reviews of prognosis studies: strategies to facilitate review production and improve quality of primary research

Personalized, precision, and risk-based medicine are becoming increasingly important in medicine. These involve the use of information about the prognosis of a patient, to make individualized treatment decisions. This has led to an accumulating amount of literature available on prognosis studies. To summarize and evaluate this information overload, high-quality systematic reviews are essential, additionally helping us to facilitate interpretation and usability of prognosis study findings and to identify gaps in literature. Four types of prognosis studies can be identified: overall prognosis, prognostic factors, prognostic models, and predictors of treatment effect. Methodologists have focussed on developing methods and tools for every step of a systematic review for reviews of all four types of prognosis studies, from formulating the review question and writing a protocol to searching for studies, assessing risk of bias, meta-analysing results, and interpretation of results. The growing attention for prognosis research has led to the introduction of the Cochrane Prognosis Methods Group (PMG). Since 2016, reviews of prognosis studies are formally implemented within Cochrane. With these recent methodological developments and tools, and the implementation within Cochrane, it becomes increasingly feasible to perform high-quality reviews of prognosis studies that will have an impact on clinical practice.