Objectives: To examine the association of risk factors, age, gender, and earlier opioid requirement with the rate of dose escalation in long-term opioid therapy.
Methods: This is a retrospective cohort study of 1,922 individuals identified from California's prescription drug monitoring program database who continuously used opioids from 1999 to 2007. A linear mixed-effects model was used to examine the association of age, gender, and baseline dose requirement with the rate of subsequent opioid dose change. Because of different reporting requirements before and after January 1, 2005, the analyses were conducted separately for patients' opioid use in two periods (6 years between 1999 and 2004 and 3 years between 2005 and 2007).
Results: Both the 6-year and the 3-year data showed a significant age association, with younger patients having a higher rate of dose escalation than older patients (p = 0.021 and <0.0001, respectively). Females had a lower rate of dose escalation than males, although the result did not achieve statistical significance in the 6-year data (p = 0.165 and 0.013, respectively). The higher the dose requirement a patient had at baseline, the lower the rate of dose escalation (p < 0.0001 in both periods).
Conclusions: Age, gender, and earlier dose requirement were associated with the rate of dose change in 9-year long-term opioid therapy. Patients aged 75-100 years, being female or having large dose requirement at an earlier stage of therapy may experience a slower dose escalation or even dose decline.