Summaries

Pain Medicine Highlights

The following highlights summarize selected articles from Pain Medicine (Volume 16, No. 1, January 2015 Issue).

A Brief Peer Support Intervention for Veterans with Chronic Musculoskeletal Pain: A Pilot Study of Feasibility and Effectiveness

Marianne S. Matthias, Alan B. McGuire, Marina Kukla, Joanne Daggy, Laura J. Myers, and Matthew J. Bair; VA HSR & D Center for Health Information and Communication, Roudebush VA Medical Center; Regenstrief Institute, Inc.; Departments of Communication Studies and Psychology, Indiana University-Purdue University; Departments of Biostatistics and Medicine, School of Medicine, Indiana University, IN

Peer support models, which are increasingly used to help patients manage chronic conditions, have demonstrated promising results. The purpose of this study was to pilot test a peer support model for chronic musculoskeletal pain self-management among veterans. This study, Improving Pain Using Peer-Reinforced Self-Management Strategies, examined feasibility of recruiting and retaining peer coaches and patients. The investigators hypothesized that after participating in a peer support intervention for chronic pain self-management, patients would experience increased self-efficacy, perceived social support, and patient activation, and that levels of anxiety and pain severity, interference, catastrophizing, and centrality (measures of negative pain cognitions) would decrease.

Nine peer coaches and 17 male veterans participated in the study. Patients’ pain severity and pain interference improved at 4 months compared with baseline but did not reach statistical significance. In particular, self-efficacy, pain centrality, and patient activation showed moderate effect sizes. This is potentially important because self-efficacy and patient activation (i.e., patients having the knowledge, skills, and confidence to self-manage) are integral to effective self-management. Higher levels of patient activation are associated with greater patient adherence to treatment recommendations and self-management behaviors.

Although pain centrality is a relatively new construct, decreases in centrality suggest that pain became less of a focal point in patients’ lives after the intervention, potentially facilitating their ability to cope with chronic pain. These findings suggest that veterans can effectively deliver pain self-management strategies to their peers. Although this pilot study had a relatively short intervention period, patients improved on several outcomes. Future research with a larger, more diverse sample will facilitate further examination of the effectiveness of peer support for self-management of chronic pain.

The Influence of Healthcare Professional Characteristics on Pain Management Decisions

Emily J. Bartley, Jeff Boissoneault, Alison M. Vargovich, Laura D. Wandner, Adam T. Hirsh, Benjamin C. Lok, Marc W. Heft, and Michael E. Robinson; Departments of Community Dentistry and Behavioral Science, Clinical and Health Psychology, Computer and Information Science and Engineering, and Oral and Maxillofacial Surgery, University of Florida, Gainesville; Department of Psychology, Indiana University-Purdue University, Indianapolis, IN

During the past decade, researchers have directed considerable attention toward understanding the influence of patient characteristics on pain management, with a number of studies finding ethnic minorities, women, and older adults at higher risk for substandard pain treatment. Although this trend signifies that patient demographics may be important determinants of healthcare decisions, the personal characteristics of healthcare practitioners may also influence pain-related care.

The purpose of this study was to examine the impact of healthcare providers’ characteristics (i.e., gender, race, age, duration of experience) on pain management decisions using virtual human (VH) technology. Investigators examined the extent to which characteristics of physicians and dentists impacted ratings of pain intensity and unpleasantness, as well as prescription of nonopioid and opioid analgesics for VH patients.

Results indicate that practitioner demographics may play a significant role in pain management decisions. When compared with male practitioners, female practitioners were more likely to recommend pain treatment with nonopioid analgesics. This effect was pronounced for black VH patients. Differences in pain management decisions across patient ages emerged by practitioner race, as well—nonwhite practitioners were more likely to rate pain higher in older VH patients.

Evidence suggests that females are more emotionally expressive than males and are at higher risk for having their pain attributed to a psychological cause. This may partially explain why practitioners rated pain unpleasantness (affective component of pain) higher in females, and this suggests others may view this group as more willing to engage affective processes during the experience of pain.

Future research is needed to clarify the role that healthcare provider characteristics have on pain decision making and determine whether results replicate in other healthcare specialties and medical conditions.

PAIN Highlights

The following highlights summarize selected articles from PAIN (Volume 156, No. 2, February 2015 Issue).

Association of Functional Variations in COMT and GCH1 Genes with Post-Herniotomy Pain and Related Impairment

Inna Belfer, Feng Dai, Henrik Kehlet, Peter Finelli, Li Qin, Reinhard Bittner, Eske K. Aasvang; Departments of Anesthesiology and Human Genetics, University of Pittsburgh, Pittsburgh, PA; Yale Center for Analytical Sciences, Yale University, New Haven, CT; Section for Surgical Pathophysiology, Rigshospitalet, Copenhagen University, Copenhagen, Denmark; Department of Surgery, Marienhospital Stuttgart, Stuttgart, Germany

Environmental risk factors explain some variability in persistent postherniotomy pain (PPP), yet no study has prospectively investigated the relative contributions of genetic factors that may predict the likelihood of functional, pain-related impairment after groin hernia repair. Persistent pain is estimated to occur in 5%–10% of these patients and is considered the most serious long-term consequence of groin hernia repair procedures. PPP is multifactorial—preoperative pain intensity, nociceptive function, degree of nerve injury, and acute postoperative pain are relevant factors.

Investigators performed the study to determine whether commonly observed functional sequence variations of COMT and GCH1, the two best-studied pain modulating genes, are associated with differential outcomes post-herniotomy. Findings suggest that functional variations in COMT and GCH1 combined with clinical factors are predictive of PPP-related impairment after groin herniotomy. Prospective data from 429 Caucasian male patients with hernia were collected. Three COMT and 2 GCH1 tagging single-nucleotide polymorphisms (SNPs) were genotyped and analyzed for association with PPP-related activity impairment at 6 months after herniotomy.

Even a slight improvement of prediction value, like the improvement seen in this study, might have clinical relevance in the era of personalized medicine and individualized prediction of clinical outcomes after standard procedures. However, the fact that there was only a minimal increase in discrimination accuracy from adding GCH1 and COMT SNPs indicates that other genetic factors must be included in predictive models to achieve higher predictive power.

Both environmental (patient- and surgery-related) and genetic factors predict the likelihood of persistent pain after hernia repair, providing a rationale for selecting surgical technique and perioperative pain management based on individual patient characteristics. Based on the risk profiles, future studies should assess whether intense and prolonged analgesia in patients at high risk can reduce risk for acute and persistent pain, as well as PPP-related disability.

Effects of Testosterone Replacement in Men with Opioid-Induced Androgen Deficiency: A Randomized Controlled Trial

Shehzad Basaria, Thomas G. Travison, Daniel Alford, Philip E. Knapp, Kjersten Teeter, Christine Cahalan, Richard Eder, Kishore Lakshman, Eric Bachman, George Mensing, Marc O. Martel, Dillon Le, Helene Stroh, Shalender Bhasin, Ajay D. Wasan, Robert R. Edwards; The Research Program in Men’s Health: Aging and Metabolism, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA; Department of Biostatistics, Boston University School of Public Health, Boston, MA; Department of Medicine, Boston University School of Medicine, Boston, MA; Department of Anesthesiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA; Departments of Anesthesiology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA

Among the many risks associated with the use of opioid analgesics, androgen deficiency caused by suppression of gonadotropin-releasing hormone secretion has remained underappreciated as a common side effect, with some patients experiencing severe androgen deficiency with testosterone levels in the castrate range. Opioid-induced androgen deficiency is often associated with distressing symptoms such as sexual dysfunction, hot flashes, low mood, osteoporosis, and reduced quality of life. This randomized, double-blind, placebo-controlled parallel group trial was designed to determine the effects of testosterone replacement on clinical and experimental pain, sexual function, body composition, and health-related quality of life in men with opioid-induced androgen deficiency.

Participants were randomly assigned to 14 weeks of daily transdermal gel that contained 5 g of testosterone or placebo. Changes in self-reported clinical pain and objectively assessed pain sensitivity were primary outcomes. Sexual function, quality of life, and body composition were also assessed.

Testosterone administration was associated with reduced sensitivity to multiple modalities of experimentally induced noxious stimuli, including pressure algometry and repetitive noxious punctate stimuli. The men given testosterone did not experience significant improvement in self-reported clinical pain. Restoration of serum testosterone levels improved pain sensitivity, and men in the testosterone group showed significant improvement in sexual desire and body composition compared with those in the placebo group. The improvement in body composition is important because men on opioids are susceptible to the development of metabolic abnormalities and cardiovascular disease. Men in the testosterone group experienced a significant reduction in fat mass and an improvement in lean body mass compared with those in the placebo group.