Utilization characteristics and treatment persistence in patients prescribed low-dose buprenorphine patches in primary care in the United Kingdom: a retrospective cohort study.

The 7-day, low-dose buprenorphine patch has been available in the United Kingdom since 2005 for the treatment of chronic nonmalignant pain that is unresponsive to nonopioid analgesics. Osteo-arthritis pain, a significant cause of pain and disability in the elderly, is a common reason for prescribing bu-prenorphine patches. The goals of this study were to investigate utilization and treatment persistence in patients receiving low-dose buprenorphine patches and the expected patterns of treatment 12 months after the initiation of treatment. This was a retrospective cohort study of patients who were prescribed low-dose buprenorphine patches in general practice in the United Kingdom. Patients in this cohort were matched by age, sex, and practice with comparator cohorts prescribed oral codeine, dihydrocodeine, or tramadol. Data on baseline characteristics, utilization, and adverse events were obtained from the General Practice Research Database, which contains computerized medical records from UK general practice. Treatment persistence was determined based on repeat prescribing within 90 days after the expected end of a prescription; rates of persistence were compared between the buprenorphine and comparator cohorts. Cox proportional hazards regression models were used to compare the incidence of typical opioid adverse effects (constipation, dizziness, and nausea and/or vomiting) between cohorts. The study cohort included 4968 patients who were prescribed low-dose buprenorphine patches. The majority of patients (64.2%) were aged >65 years, and the most frequently recorded indication for low-dose buprenorphine patches was osteoarthritis (48.7%). Most patients (76.1%) started treatment at the lowest patch strength (5 microg/h). The mean patch strength prescribed over time stabilized at 10 to 12 microg/h. Persistence with low-dose buprenorphine patches over 6 months was significantly higher than with codeine, dihydrocodeine, and tramadol (28.9%, 22.4%, 24.4%, and 23.8%, respectively; P < 0.01). Persistence over 12 months also was significantly higher with low-dose buprenorphine patches compared with the comparators (18.5%, 16.1%, 18.0%, and 17.6%; P < 0.01). After 12 months, the difference in persistence levels between cohorts was not statistically significant. In the Cox proportional hazards regression models, patients using buprenorphine patches had an increased incidence of constipation, dizziness, and nausea and vomiting compared with those who used the comparator opioids (P < 0.05). Significantly more patients receiving low-dose buprenorphine patches in this study persisted with treatment at 6 and 12 months compared with those receiving other opioid analgesics. Treatment with low-dose buprenorphine patches was most frequently initiated at the lowest patch strength and stabilized at a mean of 10 to 12 microg/h.