Epidemiology of pain among drug users in methadone maintenance

Aim: To identify the prevalence, characteristics, and psychosocial impact of pain among drug users (DUs) in Methadone Maintenance (MM).

Methods: Participants in a clinical trial of a hepatitis care coordination intervention for DUs in MM were surveyed using the Brief Pain Inventory-Short-Form. Clinically significant pain was defined as a score of >=5 on the “average pain” intensity item or a mean pain interference score of >=5.

Results: Of the 489 participants, 32% were female; 31% Hispanic, 29% Black, 36% White; mean age 45 years; mean methadone dose 90mg; 10% were HIV infected. Overall, 46.7% (229) reported clinically significant pain. Further, 42% reported receiving prescription medications for pain treatment, of whom 66% felt they needed stronger pain treatment. Baseline urine drug screening indicated that (UDS) 39%, 34% and 20% tested positive for cocaine, opiates, and benzodiazepines (including prescribed medications) respectively - there were no significant differences among those with or without pain in the frequency of positive UDS. Those with pain had higher mean Beck Depression Inventory scores (M = 22 versus M = 19, respectively; p < .018) and worse scores on quality of life domains (using the Short-Form-12), including poorer general health, physical, emotional and social functioning, role physical, role emotional, and vitality (p's < .001).

Conclusions: There is a high level of pain and symptom burden among DUs in MM. Although many MM patients reported receiving prescribed pain medications, many may be at considerable risk for under-treatment of pain.