Patterns of community-based opioid prescriptions in people dying of cancer

Studies of opioid use in cancer patients have been cross-sectional or have focused on mean consumption over a specific time interval.

This study aimed to determine the temporal pattern of prescribed opioids at a population level.

Using Quebec administrative databases, we ascertained details of cancer-related deaths and filled community-based opioid prescriptions (COPs) in 48,420 decedents from 2003 to 2006.

Using group-based trajectory modeling, based on when people started to fill COPs, our population-based study demonstrated patterns of filled COPs with six distinct trajectories. An earlier start in opioid consumption resulted in a higher group average morphine daily dose; those who were already filling COPs at study entry (5.2%) had a final dose of more than 300mg by the time of death. Remarkably, 58.8% of people had not filled COPs with a biweekly average greater than 1mg earlier than two weeks before death, marking the end of follow-up. Breast cancer in women, prostate or colorectal cancer in men, and younger age and multiple myeloma in both sexes were positively associated with earlier filling of COPs.

Patients dying of cancer require increasing doses of opioids over time; although we cannot distinguish the relative contributions of disease progression and opioid tolerance, age and certain cancers seem related to this phenomenon. Given the potentially prohibitive cost of prospective epidemiological studies, more elaborate clinical administrative databases that include regular pain assessment are necessary to determine optimal opioid use and factors associated with dose increases over time at a population level.