This secondary analysis investigated the role of pain on illicit opioid use during opioid detoxification treatment. Consistent with prior reports, pain was a common problem reported by the majority of participants at baseline and follow-up. Overall, results regarding the role of pain in predicting treatment outcome were mixed. Moderate-to-severe pain at baseline was associated with treatment success (urine toxicology results) at the end of detoxification. It is possible that individuals experiencing more pain prior to entering treatment, perhaps related to withdrawal symptoms experienced during the month prior to detoxification, were more motivated to stay in detoxification.
However at follow-up, there was no association between moderate-to-severe baseline pain and urine drug screen results. While this could represent a true negative finding, some methodological features of both the main study and our analytic strategy may have contributed to this result. As in the original study, we adopted a conservative approach in which individuals who did not complete the follow-up visit were assumed to have an opioid-positive urine result. Thus, a sizable number of participants were deemed opioid-positive because of failure to attend this follow-up interview, but, we found no association between attending the follow-up visit and pain status.
In contrast to the above, at follow-up, more pain (as measured by the BP) was associated with more days of opioid use. This finding was observed after adjusting for baseline BP and self-reported opioid withdrawal symptoms during detoxification. This is consistent with previous research suggesting that pain worsens SUD outcomes, including those for opioid dependence (Caldeiro et al., 2008
; Larson et al., 2007
). It is important to note that the BP includes two elements of pain (intensity and interference) rather than just pain intensity as with the moderate-to-severe pain measure. Thus, our findings suggest that continued research regarding the role of pain on substance abuse treatment outcomes is warranted.
Further, these results support that physical pain is experienced by a sizable proportion of individuals entering detoxification. Although pain is a known withdrawal-related symptom, it may be important to assess and address pain reported during and immediately following detoxification more vigorously and explicitly as it may be a risk factor for relapse. Moreover, given the relative lack of awareness of pain in SUD treatment settings and the potential for participants with pain to be seen as difficult and “medication (or drug)-seeking” (Merrill, Rhodes, Deyo, Marlatt, & Bradley, 2002
; Modesto-Lowe, Johnson, & Petry, 2007
), it is understandable that pain might not be at the forefront of the treating clinician’s attention. Assessing and addressing pain is encouraged increasingly in most health care settings including behavioral health care settings, for example the Joint Commission (Lanser & Gesell, 2001
) and Veteran’s Health Administration (Veterans Health Administration National Pain Management Strategy, 1998
). The findings discussed above, although exploratory, add to the literature because this research focuses on a detoxification sample using bup-nx for detoxification, and directs attention to pain experienced during and immediately following detoxification.
These results have limitations. As with all secondary data analyses, this was exploratory work intended to generate future hypothesis-driven research. Our sample only included individuals who received a 14-day detoxification using bup-nx, and results should not be generalized to detoxification using other medications and schedules. The high attrition rate from baseline to follow-up limited the sample available for analysis at follow-up. While we did not observe a differential attrition rate between those with and without moderate-severe pain, our analyses are limited by the fact that only 59% of participants randomized returned for the follow-up visit. Thus, interpretation of these results must be made with caution. Finally, because pain was not a primary focus of the original study, our ability to assess pain was somewhat limited. While the SF36v2 BP captures two important components of pain (intensity and interference), this is not a comprehensive measure of pain. In addition, pain was only assessed at baseline and follow-up. As a result, we were unable to discriminate pain experienced during detoxification from pain experienced after detoxification. Similarly, we were unable to distinguish acute pain from chronic pain or to isolate the reason for the pain (e.g., withdrawal pain). This is important because different types of pain may have different implications for substance abuse treatment outcomes. For example, the pain that participants reported at baseline might have resulted from pre-existing chronic pain problems (with various etiologies), opioid-related withdrawal pain, a combination of these two, or some other reason.
Despite these limitations, the results suggest potentially important clinical implications regarding pain management during the detoxification process that warrant continued research. This is, to our knowledge, the first report describing pain and its association with SUD outcome among individuals receiving bup-nx for opioid detoxification in a controlled clinical trial. As such, our findings extend previous reports indicating that persistent pain is associated with negative SUD treatment outcomes and confirm the importance of examining co-occurring physical pain in SUD populations (Caldeiro et al., 2008
; Ilgen et al., 2006
; Larson et al., 2007
Research on co-occurring pain and substance use disorders is relatively new, To advance our understanding of the potential clinical implications of pain on substance abuse treatment, comprehensive and systematic pain assessment that goes beyond pain severity to include etiology, course, and functional impairment is critical. It is important that we better understand the role of pain, acute and chronic, in maintaining substance use. Finally, we need to determine the extent to which currently available pharmacological and psychosocial treatments for substance use disorders are effective in individuals with co-occurring pain.