Opioid drug utilization and cost outcomes associated with the use of buprenorphine-naloxone in patients with a history of prescription opioid use.

BACKGROUND

Management of opioid dependence is associated with many challenges such as the misuse of prescribed treatment and lack of medication adherence that can affect the clinical outcome of the patient. Buprenorphine-naloxone was approved by the U.S. Food and Drug Administration in October 2002 as the first outpatient treatment indicated for opioid dependence. There is only 1 report in the literature on the effectiveness of buprenorphine-naloxone in a real-world setting and no reports on persistence and cost obtained from administrative claims data.

OBJECTIVES

To determine (1) the length and cost of therapy with oral buprenorphine-naloxone, and (2) the cost avoidance for opioid dependence as measured by opioid utilization and opioid drug cost obtained from pharmacy claim records.

METHODS

The patients for this drug use evaluation (DUE) were identified from a New Jersey managed care organization (MCO) with approximately 1.8 million members with pharmacy benefits who (a) were continuously enrolled from October 1, 2004, through September 30, 2006; (b) had their first buprenorphine-naloxone pharmacy claim during the fixed 6-month initiation period (April 1, 2005, through September 30, 2005); and (c) had at least 1 opioid pharmacy claim in the 6-month pre period preceding the 6-month initiation period. The outcome measures included the number of opioid pharmacy claims, daily dose, days supply, and cost defined as opioid ingredient cost. Member cost share and net plan cost (after subtraction of member cost share) were also measured. The measurement periods for opioid use and cost were the fixed calendar periods for 6 months from October 1, 2004, through March 31, 2005, and for 12 months from October 1, 2005, through September 30, 2006. Persistence in the 12-month follow-up period was defined as a gap of 30 days or less between depletion of the days supply for the preceding pharmacy claim for buprenorphinenaloxone and the date of service (refill date) for the succeeding pharmacy claim for buprenorphine-naloxone.

RESULTS

Of the 160 new buprenorphine-naloxone users with continuous pharmacy enrollment for the 2-year period ending September 30, 2006, 84 patients (52.5%) had at least 1 opioid pharmacy claim in the 6-month pre period from October 1, 2004, through March 31, 2005, and were included in this DUE. In the 12-month post period from October 1, 2005, through September 2006, the median length of therapy with buprenorphinenaloxone was 1 month, and the mean length of therapy was 3.5 months. Only 40 patients (47.6%) had a pharmacy claim for buprenorphine-naloxone at month 1 in the 12-month post period. Persistence was 27.4% (n = 23) at 6 months (March 2006) and 20.2% (n = 17) at 12 months (September 2006) in the post period. A total of 24 study patients (28.6%) had no opioid pharmacy claims other than buprenorphine-naloxone in the 12-month post period. Utilization of opioids decreased by 18.8%, from 1.49 opioid pharmacy claims per patient per month (PPPM) in the pre period to 1.21 claims PPPM in the post period (P = 0.031). Excluding the 0.42 buprenorphine-naloxone claims PPPM, opioid utilization decreased by 47.0%, from 1.49 claims PPPM to 0.79 claims PPPM (P < 0.001) in the 12-month post period. Before subtraction of member cost share, the actual drug cost of opioids including buprenorphine-naloxone appeared to be 26.9% lower ($156.24 PPPM) in the post period compared with $213.74 PPPM in the pre period, but the difference was not statistically significant (P = 0.254). Excluding the cost of the buprenorphine-naloxone, actual opioid drug cost decreased 66.5% from $213.74 PPPM pre period to $71.65 PPPM post period (P = 0.047).

CONCLUSIONS

Approximately one half of the patients who had a new claim for buprenorphine-naloxone were excluded from this study because there was no utilization of prescription opioids in the 6 months prior to initiation. For patients with documented use of prescription opioids prior to initiation, treatment with buprenorphine-naloxone was associated with a reduction in opioid utilization and cost in the first year of follow-up. Persistence was only 27% at 6 months and 20% at 12 months, and there were no drug cost savings in the follow-up period when the actual cost of the buprenorphine-naloxone therapy was included.