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 non-opioid 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.