Wednesday, February 06, 2019 Researchers: Physical Therapy-Related Cochrane Reviews Largely Inconclusive The Cochrane Database of Systematic Reviews is widely considered the “gold standard” for health care professionals who want to know what current, high-quality research says about the efficacy of various interventions. But when it comes to physical therapy, a “researcher or clinician would not necessarily be able to turn to [Cochrane reviews] for a definitive answer” on a treatment strategy, write authors of an article in the International Journal of Rehabilitation Research (abstract only available for free). Reviewers for the Cochrane Collaboration—an international network of subject-matter groups that produces evidence-based resources—are known for their systematic analysis of evidence obtained from randomized clinical trials and provide recommendations for specific interventions. Like any systematic review, Cochrane reviews (CRs) are based on the existing research, and randomized controlled trials vary in quality. For the Rehabilitation Research study, a multidisciplinary group of researchers in Japan turned to physical therapy to find out what CRs had to say about various interventions. They examined 283 CRs to evaluate just how conclusive the evidence is with regard to physical therapy, as well as what factors influence the degree of conclusiveness. Authors classified a CR as “conclusive” if it identified a particular intervention as “superior to another” or found that interventions are “equivalent.” Inconclusive reviews concluded that “no decision can be made.” While the authors acknowledge that CRs “often show a lack of strong evidence for the efficacy of a particular treatment or strategy,” they found that an overwhelming majority of reviews related to physical therapy—94.3%—were inconclusive and recommended further study, a rate higher than in many other areas of study. Reviews that evaluated a larger number of trials or included greater total numbers of patients were more likely to list conclusive results; still, even among CRs with conclusive results, 68.8% recommended further study. According to the authors, many factors were associated with recommendations for further research, including low-quality study design, small sample sizes, too few available studies, and not enough data on participant subgroups or on adverse effects. “The low proportion of conclusive studies may be attributable to the poor quality of evidence” in physical therapy, the authors write, noting, however, that, unlike other areas of study, blinded randomized controlled trials are “often hard to achieve” in physical therapy research. Authors emphasized that although inconclusive reviews cannot assist in clinical decision making, “high-quality inconclusive reviews…are of great value” to identify gaps in the literature and areas for further study. And while there's much work to be done to increase the number of physical therapy-related CRs with conclusive recommendations, authors think the effort is worthwhile—and timely. “Trials in physiotherapy are worth conducting, as the field is positioned as a new frontier and is receiving much attention," they write. "Future research in physiotherapy and further development of the [Cochrane Collaboration] are eagerly awaited.” Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.