Characteristics of patients receiving long-term opioid therapy for chronic noncancer pain: a cross-sectional survey of patients attending the Pain Management Centre at Hamilton General Hospital, Hamilton, Ontario

Abstract

Background: Characteristics of patients receiving long-term opioid therapy (≥ 6 months) for chronic noncancer pain are poorly understood. We conducted a cross-sectional survey of this patient population to explore demographic variables, pain relief, functional improvement, adverse effects and impressions of an educational pamphlet on long-term opioid therapy.

Methods: We invited 260 adult patients presenting to the Pain Management Centre at the Hamilton General Hospital, Hamilton, Ontario, with chronic noncancer pain to complete a 20-item survey. Patients who presented for procedures were not eligible for our study. We used adjusted logistic regression models to explore the association between higher morphine equivalent dose and pain relief, functional improvement, adverse events and employment.

Results: The survey was completed by 170 patients (a response rate of 65.4%). Most respondents (87.6%; 149 out of 170) were receiving long-term opioid therapy, and the median morphine equivalent dose was 180 mg daily (interquartile range 60-501). Most respondents reported at least modest (> 40%) opioid-specific pain relief (74.1%; 106 out of 143) and functional improvement (67.6%; 96 out of 142), and 46.5% (66 out of 142) reported troublesome adverse effects that they attributed to their opioid use. Most patients were receiving disability benefits (68.3%; 99 out of 145) and, among those respondents who were less than 65 years of age (90.3%; 131 out of 145), 10 (7.6%) were working full-time and 14 (10.7%) part-time. In our adjusted analyses, higher morphine equivalent dose was associated with greater self-reported functional improvement (odds ratio [OR] 1.45, 95% confidence interval [CI] 1.07-1.96) but not with pain relief (OR 1.38, 95% CI 1.00-1.89), troublesome adverse effects (OR 0.92, 95% CI 0.70-1.20) or employment (OR 0.80, 95% CI 0.56-1.15).

Interpretation: Most outpatients receiving long-term opioid therapy for chronic noncancer pain at a tertiary care chronic pain clinic reported at least moderate pain relief and functional improvement; however, adverse effects were common and few patients were engaged in competitive employment.

Figure 1:

Flow chart for patient selection.