Pain is a worldwide epidemic and more than a third of all adults, or 100 million persons, in the U. S. alone suffer from chronic pain conditions of some sort, as estimated by the U.S. Institute of Medicine (IOM 2011). Even more troubling, newly published research suggests that the prevalence of clinically significant, persistent pain among patients in methadone maintenance treatment (MMT) programs is nearly twice that of the general population—and most of that chronic pain is going untreated.
Survey Provides Bleak Picture of Pain in MMT
Writing recently in the journal Pain Medicine, Kelly E. Dunn, PhD, and colleagues reported on a survey of MMT patients at the Johns Hopkins Bayview Medical Center in Baltimore, Maryland (Dunn et al. 2014). Approximately 80 percent of all patients at the clinic responded to a self-report questionnaire widely used in the pain field—the Brief Pain Inventory (BPI)—which assesses severity of pain and its interference with daily activities. Additional data were gathered on patient demographics, pain location, drug use, and current treatments for pain and addiction.
Overall, the 227 survey participants were 45 years old, had been in MMT for 4.5 years on average, and roughly half were male (47%) and Caucasian (49%). Sixty percent of respondents (N=137) indicated on the BPI that they had chronic pain. Also, there were some statistically significant differences in this group compared with MMT patients not reporting such pain: Patients with chronic pain were older (mean age 46 vs. 42 years, respectively), had higher average daily methadone doses (86 mg/d vs. 71 mg/d), and had a higher rate of benzodiazepine-positive urine samples in the past 90 days (7% vs. 3%).
Chronic pain was reported in multiple body areas by roughly a third (36%) of patients with pain, but the most common locations were the back (51%) and lower extremities (59%). Average pain during the past 24 hours on a 0-to-10 scale was reported as 5.8, with worst pain averaging 7.2. Also, using a 10-point scale to rate how pain affected daily life, interference with sleep was ranked highest (6.0 on average), followed by interference with general activity, normal work, and enjoyment of life. Interference in relationships with other people was least affected by chronic pain (rated 4.1 on average).
Merely 13 percent (N=18) of study participants with chronic pain reported receiving pain management treatment, and these patients were significantly more likely to be female, report less income from employment, and have a lower rate of benzodiazepine use. MMT patients being treated for pain most commonly reported back pain, and the majority of those being treated (89%) were prescribed medications; half received short-acting opioids and a third received nonopioid medications (eg., NSAIDs, gabapentin). Only 28 percent received nonpharmacologic therapies for their pain, such as physical therapy. Overall, those treatments were effective; study participants indicated that pain management provided, on average, 51 percent relief from their pain (range 0%-90%).
In sum, this study found that a substantial proportion of patients in a large MMT program reported clinically significant and persistent pain, for which only a relative handful were receiving pain management therapy. Dunn and her coauthors state, “Overall these data suggest that pain was not being adequately evaluated or treated in the majority of this sample. These findings are remarkable . . . and they illustrate what little progress has been made in the past 10 years regarding the concurrent treatment of pain and opioid use disorders.”
Better and More Research is Needed
Similar to Dunn et al., in 2008, Cruciani and colleagues reported a study that found 61 percent of 390 MMT patients had experienced persistent pain for more than 6 months, and greater than a third of those patients (37%) had severe chronic pain (Cruciani et al. 2008). In an Addiction Treatment Forum interview article last year (see AT Forum, Winter 2013), it was noted that pain in patients attending MMT programs is commonplace, and a recent study of 489 patients had found that 237 (48.5%) had clinically significant chronic pain. Generally, past research surveys have reported high but varying prevalences of chronic pain among MMT patients, ranging from approximately 27 percent to 80 percent, with relatively few receiving pain care (references in Dunn et al. 2014).
While the newly reported study by Dunn and colleagues is consistent with most of the past research, it also exhibits many of the limitations in this area of scientific inquiry:
- Dunn et al. gathered data for their study between December 2006 and January 2007, but were just reporting on results now in 2014; so, the outcomes may or may not reflect current circumstances. Unfortunately, it is not unusual in the pain research literature or government surveys for the reporting of data to come long after its collection.
- Chronic pain was defined in the Dunn et al. study as answering “yes” to the BPI question, “Have you had pain other than everyday kinds of pain today?” And, even though locations of pain also were reported by patients and recorded by the investigators, this was a somewhat vague definition of chronic pain.This is a common problem encountered in most surveys of chronic pain, since there usually are no readily observable clinical signs or imaging evidence (eg., on X-ray, MRI) of pathology to confirm the presence, severity, or duration of pain. Pain most often is what the patient says it is, without sufficient clinical confirmation; so, it is understandable that there are wide variations in the prevalence of pain reported in different studies of pain in MMT patients, as well as in the general population.
- There was a small, but significant, increase in benzodiazepine use among patients with pain (small differences between groups in illicit opioid and cocaine use were not statistically significant). However, considering that sleep disturbance was ranked high in persons with pain, this might account for their greater use of sedatives like benzodiazepines; additionally, Dunn et al. did not distinguish between prescribed vs. illicit use of these medications.
- There was no assessment by Dunn et al. of which came first, pain or addiction, patients’ histories of pain or its treatment, and how MMT might have affected chronic pain. For example, although patients with pain were receiving higher average methadone doses (86 mg/day), the researchers acknowledge that persistent symptoms of opioid withdrawal in some persons were likely confused with chronic pain. Dunn and coauthors also note that some patients might have been receiving certain treatments in the MMT clinic—eg., antidepressants, cognitive behavioral therapy, biofeedback—that were intended for pain management, but not identified as such.
- In general, the study by Dunn and colleagues surveyed a relatively small sampling of MMT patients in a single clinic setting, which cannot be assumed to represent the larger MMT population. While they present statistical data on those patients receiving pain care during MMT, their numbers were so small (N=18) that the validity of results in this group need confirmation in a larger sampling. For example, the findings that patients receiving pain care were more likely to be women, making less money from employment, and less likely to be using benzodiazepines should be cautiously considered in view of such small numbers.
Dunn et al. do not speculate as to why there is such a high prevalence of chronic pain among MMT patients, or why so few patients receive pain management for those conditions. Clearly, more and better research is needed to understand these problems and to develop strategies for providing effective pain management in the presence of the disease of addiction. At the least, there is a need for prospective studies examining large numbers of patients upon entry to MMT—or buprenorphine therapy—for addiction and during long-term follow-up to determine the progress of those with clinically diagnosed pain conditions.
Challenges and Opportunities
As Dunn and colleagues point out, patients with opioid addiction are likely being “systematically undertreated for pain.” And, while surveys have found that MMT clinic staff are interested in receiving education on treating pain in persons with substance-use disorders, there could be important barriers for MMT patients when it comes to receiving adequate pain care.
Opioid analgesics have been demonstrated as effective for relieving most types of moderate to severe pain, although their long-term use for chronic pain needs further investigation. Dunn and colleagues found that half of their respondents being treated for pain (N=9) were administered short-acting opioids, and Cruciani et al. similarly had noted that 47 percent of MMT patients with pain in their survey were receiving opioid pain relievers. Methadone itself is an excellent analgesic; however, to be effective for pain, it requires more frequent administration than the once-daily (or even split-dose) regimen provided during MMT for addiction. At the same time, many staff in MMT programs are uneducated in, or uncomfortable with, the concurrent administration of methadone and other opioids.
Often multiple types of pain treatment are necessary—spanning the medication and nondrug spectrums—which can be costly and required for extended periods of time. Yet, Dunn and her coauthors note, patients in addiction treatment have historically had limited access to insurance or other financial resources for such care. Furthermore, the pain-care field is highly fragmented, with the various specialists—eg., rheumatologists, orthopedists, neurologists, physiatrists—in high demand and short supply in most communities.
Dunn et al. conclude that their study should illustrate to health care professionals in both the substance abuse treatment and pain management fields that “patients with both disorders are not necessarily intractable hopeless cases and that they deserve the same level of attention and clinical care as chronic pain patients in the general population.” However, unless the many challenges are overcome, the plights of persons with chronic pain in methadone or buprenorphine maintenance treatment are unlikely to improve. There is an important opportunity here for the addiction treatment and pain care fields to forge alliances that can serve the mutual goal of achieving better care for patients with co-occurring pain and opioid use disorders.
Cruciani RA, Esteban S, Seewald RM, et al. MMTP patients with chronic pain switching to pain management clinics. A problem or an acceptable practice? Pain Med. 2008;9(3):359-364. doi: 10.1111/j.1526-4637.2006.00224.x. http://www.ncbi.nlm.nih.gov/pubmed/18366514
Dunn KE, Brooner RK, Clark MR. Severity and interference of chronic pain in methadone-maintained outpatients [Epub ahead of print April 7, 2014]. Pain Med. doi:10.1111/pme.12430. http://www.ncbi.nlm.nih.gov/pubmed/24703517
IOM (U.S. Institute of Medicine). Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. June 2011. http://www.iom.edu/Reports/2011/Relieving-Pain-in-America-A-Blueprint-for-Transforming-Prevention-Care-Education-Research.aspx.
Stewart B. Leavitt, MA, PhD, is a former editor of Addiction Treatment Forum and most recently was director/editor of Pain Treatment Topics.