Treating Patients with Chronic Pain and Comorbid Substance Use Disorders

AUSTIN, TXPatients with chronic pain and comorbid substance use disorders (SUD) need more intensive and supplementary treatment to gain clinically significant improvements in pain-related function, according to a systematic review reported upon during the American Pain Society's 30th Annual Scientific Meeting.

Chronic pain affects up to 35% of the U.S. population and approximately 15% of individuals experience pain on a daily basis, said Benjamin J. Morasco, PhD, Portland VA Medical Center, Oregon Health & Science University in Portland. Chronic pain problems include variability in symptoms, low recovery rates, increased medical utilization, high psychological comorbidity, and decreased quality of life.

Comorbid SUDs are common among patients with chronic pain, but research is limited, he noted, and no published randomized trials have examined a medication or psychological intervention in this population. In addition, prevalence rates vary widely across studies and data are limited regarding treatment options. For example, incidence of patients with pain and current SUD range from 11% to 35% in an outpatient pain clinic, 5% to 23% in an inpatient pain clinic, and 3% to 10% in a primary care clinic. In those with pain and a history of SUD, incidence ranges from 16% to 48% in a pain clinic, 28% to 42% in the primary care setting, and 74% in the emergency department.

Patients with a comorbid SUD are potentially more difficult to treat, and concern exists around other comorbidities, such as depression and anxiety. There is also an increased risk for aberrant medication-related behaviors, although the presence of a SUD is not necessarily a contraindication to treatment with opioids, he said.

To assess the prevalence, associated demographic and clinical characteristics, and treatment outcomes for primary care patients with chronic pain and comorbid SUD, Morasco and colleagues examined 12-month follow-up data from patients treated in five primary care clinics of the Portland VA Medical Center enrolled in a prospective, randomized trial of a collaborative intervention for chronic musculoskeletal pain and depression.1 Results of this study found intervention using assistance with pain treatment (ie, a collaborative care approach) resulted in meaningful improvements for this population with substantial baseline disability/comorbidity.1

In the secondary analysis,2 they sought to determine if any variables assessed at baseline were associated with treatment outcomes. Of 362 patients, 72 (20%) had a history of SUD, including alcohol (86%), cannabis (14%), opiates (prescribed or illicit; 8%), amphetamines (3%), or other (18%).

Compared with those who had pain only, patients with pain and SUD were found to be younger (mean age, 58 vs. 63 years; P=0.001), married (47% vs. 63%; P=0.01), and had a current opioid prescription (40% vs. 26%; P=0.02). Bivariate comparisons also found statistically significant differences in pain-related function (16% vs. 4%; P=0.01); major depressive disorder (26% vs. 15%, P=0.01); PTSD (25% vs. 14%; P=0.02), and positive alcohol misuse screen (11% vs. 4%; P=0.02).

For patients randomized to collaborative care, the overall model was not significant and no factor predicted outcome. For patients randomized to usual care, however, the overall model was significant, and the only predictor of treatment outcome was history of SUD (OR 0.30 [0.11-0.82]). Morasco and colleagues found patients with chronic pain and a history of SUD had poorer functioning at baseline, were more likely to be prescribed an opioid and, for those randomized to usual (vs collaborative) care, were 70% less likely to have a clinically significant improvement in pain functioning. For those randomized to collaborative care, SUD status was not associated with long-term functioning.

Barriers to high quality pain care include clinician reliance on the biomedical (as opposed to the biopsychosocial) model; unrealistic expectations from patients; lack of time, system support, and access to resources; and comorbid depression, including problems with recognition and attribution of symptoms.

Future recommendations include incorporation of multidisciplinary treatment; utilization of treatment guidelines for patients prescribed opioids; providing relapse prevention, including referrals to substance abuse treatment if patients are active users; and providing more intensive and integrated treatment.

References

1. Dobscha SK, Corson K, Perrin NA, et al. Collaborative care for chronic pain in primary care. JAMA. 2009;310:1242-1252.

2. Morasco BJ, Corson K, Turk DC, Dobscha SK. Association between substance use disorder status and pain-related function following 12 months of treatment in primary care patients with musculoskeletal pain. J Pain. 2011;12(3):352–9. Epub 2010 Sep 20.