Reproducing Results
Among the deepest problems plaguing medical research has been reproducibility--or rather the lack of reproducibility.
Let’s say a researcher conducts a study and finds an interesting association between some intervention and some outcome. Naturally, another research group tries the same analysis in another dataset, and -- guess what -- it often doesn’t find the same result.
This difficulty in reproducibility holds not only in retrospective studies but also in clinical trials most likely to guide clinical decision making (even while randomization is intended to bypass confounders). Contradictory results might make us suspicious that the first “positive” finding might have been due to chance rather than some biological connection between intervention and outcome.
Meta-Analyses and Cochrane Reviews
Enter meta-analyses. By reviewing aggregated data across multiple similar studies in different populations, clinicians can have more confidence that a particular intervention will have an effect in any one patient. In the era of evidence-based medicine, as clinicians base their decisions off large prospective trials, they should ask the following question: does my patient have the relevant characteristics of the study population? The greater the number of trials that show an effect, the greater the confidence that the answer to this question is “yes.”
The Cochrane Library, and in particular, Cochrane Reviews, is perhaps the most trusted source of meta-analyses that address this issue for various clinical questions. Studies published in Cochrane seek to adjudicate the quality of evidence in support of or against a particular clinical practice.
Cochrane Reviews, Psychotherapy, and Chronic Pain
Over the years, authors publishing in Cochrane Reviews have returned to the question of whether psychotherapy is an effective treatment modality for chronic pain.
In August, a new Cochrane review on this question was published. The results were unsurprising: of the three mental health therapies studied (Cognitive Behavioral therapy (CBT), Behavioral Therapy, and Acceptance and Commitment Therapy), CBT had the largest evidence base.
The authors found 59 studies of CBT that met their inclusion criteria. CBT had small benefits in pain, distress, and disability, with a ‘moderate’ grade for quality of evidence. More specifically, six-month checkups showed pain improvement maintenance. The effects of CBT, however, were somewhat less when compared to an active control than when compared to ‘treatment as usual.’ This discrepancy highlights larger problems in prospective randomized trials in psychotherapy.
The results of other types of psychotherapy modalities were of lower quality and less consistent.
CBT and Chronic Pain
Consistent but small improvements in pain outcomes may not seem like breakthrough stuff for mental health care and mental health professionals. But in the treatment of chronic pain, for which the evidence for many of the pharmacotherapeutics and interventions are mixed, these results should not be dismissed. CBT has relatively limited adverse effects and the results seem to last.
Chronic pain can be a debilitating condition, and this work supports the idea that CBT can be not only an important type of therapy to treat mental health problems but also an important adjunctive intervention for pain management and to treat chronic pain.
David Liebers, MD
David Liebers, MD, MPH is a recent graduate of Harvard Medical School
