Methodological Issues in Systematic Reviews of Prognosis and Prognostic Factors
Background. Systematic reviews that aim to integrate the results of a number of studies are important for evidence-based practice. Systematic reviews of prognosis have been increasingly published, however, there is limited methodological guidance available. We studied research from the area of low back pain to inform this thesis.Methods. We conducted studies in three stages. Exploration stage included a 'review of reviews' of 15 low back pain prognosis reviews, and a broad systematic review of 69 low back pain prognosis studies. Acquiring Direction stage addressed three areas of uncertainty in methods. We developed broad and topic-specific guidelines to assess study quality, classified low back pain prognostic factors, and developed a framework for understanding prognosis study approaches. Application stage used best methods and insight to conduct a focused systematic review of one potential prognostic factor for low back pain.Results. We present current methods and highlight gaps for five steps of prognosis reviews: (1) clearly defined review question, (2) comprehensive searches and supplemental methods to identify and select studies, (3) assess quality by judging risk of biases, (4) data collection standard and clear, and (5) synthesize results on the direction, size, consistency and strength of evidence. Low back pain prognosis research suffers from poor quality and reporting. Consistent findings, however, suggest longer disability associated with: older age, poor general health, increased psychological stress, modified duties, poor work-relations, heavy work, worse baseline functional disability, sciatica, and presence of compensation. Lawyer involvement was consistently associated with worse low back disability outcomes across heterogeneous studies.Conclusions. Methods in systematic reviews of prognosis studies are just beginning. This thesis has importantly set the groundwork for programs of research further investigating the methods of systematic reviews of prognosis studies and the prognosis and prediction of low back disability.Objectives. Our objectives were to investigate systematic review methods for determining prognosis and prognostic factors for low back pain with both content and methodological foci. We aimed to make recommendations for conducting systematic reviews of prognosis, and synthesize current knowledge regarding low back pain prognosis.