Interpreting the clinical importance of group differences in chronic pain clinical trials: IMMPACT recommendations

Robert H. Dworkin, Dennis C. Turk, Michael P. McDermott, Sarah Peirce-Sandner, Laurie B. Burke, Penney Cowan, John T. Farrar, Sharon Hertz, Srinivasa N. Raja, Bob A. Rappaport, Christine Rauschkolb, Cristina Sampaio

Research output: Contribution to journalReview articlepeer-review


An essential component of the interpretation of results of randomized clinical trials of treatments for chronic pain involves the determination of their clinical importance or meaningfulness. This involves two distinct processes-interpreting the clinical importance of individual patient improvements and the clinical importance of group differences-which are frequently misunderstood. In this article, we first describe the essential differences between the interpretation of the clinical importance of patient improvements and of group differences. We then discuss the factors to consider when evaluating the clinical importance of group differences, which include the results of responder analyses of the primary outcome measure, the treatment effect size compared to available therapies, analyses of secondary efficacy endpoints, the safety and tolerability of treatment, the rapidity of onset and durability of the treatment benefit, convenience, cost, limitations of existing treatments, and other factors. The clinical importance of individual patient improvements can be determined by assessing what patients themselves consider meaningful improvement using well-described methods. In contrast, the clinical meaningfulness of group differences must be determined by a multi-factorial evaluation of the benefits and risks of the treatment and of other available treatments for the condition in light of the primary goals of therapy. Such determinations must be conducted on a case-by-case basis, and are ideally informed by patients and their significant others, clinicians, researchers, statisticians, and representatives of society at large.

Original languageEnglish (US)
Pages (from-to)238-244
Number of pages7
Issue number3
StatePublished - Dec 5 2009


  • Chronic pain
  • Clinical importance
  • Clinical meaningfulness
  • Effect size
  • Group differences
  • Randomized clinical trials

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Anesthesiology and Pain Medicine

Fingerprint Dive into the research topics of 'Interpreting the clinical importance of group differences in chronic pain clinical trials: IMMPACT recommendations'. Together they form a unique fingerprint.

Cite this