Quality of life associated with daily opioid therapy in a primary care chronic pain sample

Background: Daily opioid therapy is widely used in the treatment of chronic noncancer pain, yet there is limited empirical evidence on the relationship of opioid dosing and health-related quality of life (HRQoL) in primary care settings. Methods: An analysis was conducted to assess the relationship of opioid dose to quality of life. The sample consisted of 801 chronic pain patients who were prescribed daily opioids and 93 nonopioid users recruited from the practices of 235 primary care physicians. Eight HRQoL domain scores were calculated and compared with US norms and across opioid use groups. A new modeling technique, propensity score matching analysis, was performed to adjust for potential confounding factors across 4 morphine-equivalent opioid dose groups (< 20 mg, 20-40 mg, 41-105 mg, > 105 mg). Results: HRQoL scores were significantly lower in chronic noncancer pain patients relative to the US general population regardless of opioid use. In unadjusted comparisons, those using up to 20 mg/d of opioids had the highest HRQoL scores, whereas those using > 105 mg/d had the lowest. After adjusting for potential confounders, those in the 20 mg to 40 mg/d dosing group had significantly better HRQoL scores than their non opioid-treated or higher dosed counterparts. Conclusion: Use of low- to moderate-dose opioid therapy provides an improvement in HRQoL scores for chronic noncancer pain patients compared to no opioid therapy, while high-dose opioids have a smaller positive effect that is limited to mental health quality of life and patient satisfaction, and that may not justify treatment.