Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .
Preventing chronic postsurgical pain: how much of a difference makes a difference?
AFTER surgical procedures such as amputation , mastectomy , and thoracotomy , as many as 60 % of patients continue to experience pain for at least 6 months , with approximately 10 % reporting severe pain . These chronic postsurgical pain conditions have major adverse effects on health-related quality of life , including physical functioning and emotional well-being . Unfortunately , the efficacy of existing treatments is limited and many patients remain refractory to currently available therapies . For this reason , the development of interventions that prevent chronic pain after surgery has the potential to have a major impact on public health . Substantial attention has been devoted to the hypothesis that the incidence of chronic postsurgical pain can be reduced by “ preventive ” analgesia , and the benefits of preoperative , intraoperative , and postoperative analgesic interventions have been investigated alone and in various combinations . Although the results of these studies suggest that reduced acute pain and analgesic consumption can extend beyond the duration of action of the preventive analgesic interventions , there is little evidence that chronic postsurgical pain can be prevented . Placebocontrolled r and omized clinical trials are needed to determine what specific analgesic interventions are efficacious for preventing chronic pain after what types of surgery for which patients . – 6 A critical component of future clinical trials will involve determining the clinical importance of the benefits of preventive analgesia . The results of recent studies and consensus recommendations provide a foundation for interpreting the benefits of chronic pain treatment ; however , little attention has been paid to determining what magnitudes of chronic pain prevention are clinical ly meaningful . As is true of treatment benefits , evaluating the importance of preventive benefits involves a frequently misunderstood distinction between the interpretation of the clinical importance of individual patient benefits and the interpretation of the clinical importance of group differences . The results of multiple studies have shown that individual patients consider chronic pain reductions of at least 30 % on numerical or visual analog scales to be moderately clinical ly important , whereas reductions of at least 50 % represent substantial improvements . These thresholds are based on ratings by patients of their own improvement at the end of chronic pain trials , and consistent results have been found across different chronic pain conditions and in patients administered active treatments as well as placebo . Criteria for identifying clinical ly meaningful individual improvements are necessary to categorize patients as “ responders ” or “ nonresponders , ” which makes it possible to compare the percentages of patients who achieve clinical ly important outcomes between different treatment and comparison groups . Unfortunately , criteria for determining clinical ly important improvements in patients being treated for chronic pain can not be extrapolated to those undergoing perioperative analgesic interventions to prevent chronic pain . Currently , there are no data that make it possible to determine whether patients who have not experienced chronic pain would consider its prevention after surgery important enough to undergo preoperative , intraoperative , and postoperative analgesic interventions . Evaluations of individual patient improvements associated with chronic pain treatments have emphasized pain reduction , but patients considering the prevention of conditions for which their risk is relatively low can also be expected to be particularly concerned with the adverse effects , safety risks , inconvenience , and costs of the preventive intervention . It is likely that an efficacious preventive analgesia would not completely prevent chronic pain but would instead partially reduce its incidence , intensity , or duration . Such partial preventive benefits would , of course , be even harder for patients to evaluate ; for example , would patients consider reducing pain intensity 6 months after surgery from a daily average of 4 to 2 on a 0–10 scale a clinical ly important benefit ? Would this evaluation change if this reduction in pain intensity at 6 months is known to last for another 2 yr , or if the preventive intervention requires that patients take a medication that causes sedation , nausea , and constipation for 7 days before and 30 days after their operation ? Evaluations of the clinical importance of preventive analgesia must reflect the magnitude of the reductions in chronic pain incidence , intensity , or duration that the intervention would provide . However , even small reductions in the incidence or intensity of a chronic pain condition that can last for months or even years might be considered clinical ly important by patients if Accepted for publication November 17 , 2009 . The authors are not supported by , nor maintain any financial interest in , any commercial activity that may be associated with the topic of this article
Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .