Risk Factors for Relapse and Higher Costs Among Medicaid Members with Opioid Dependence or Abuse: Opioid Agonists, Comorbidities, and Treatment History

Abstract

Clinical trials show that opioid agonist therapy (OAT) with methadone or buprenorphine is more effective than behavioral treatments, but state policymakers remain ambivalent about covering OAT for long periods. We used Medicaid claims for 52,278 Massachusetts Medicaid beneficiaries with a diagnosis of opioid abuse or dependence between 2004 and 2010 to study associations between use of methadone, buprenorphine or other behavioral health treatment without OAT, and time to relapse and total healthcare expenditures. Cox Proportional Hazards ratios for patients treated with either methadone or buprenorphine showed approximately 50% lower risk of relapse than behavioral treatment without OAT. Expenditures per month were from $153 to $233 lower for OAT episodes compared to other behavioral treatment. Co-occurring alcohol abuse/dependence quadrupled the risk of relapse, other non-opioid abuse/dependence doubled the relapse risk and severe mental illness added 80% greater risk compared to those without each of those disorders. Longer current treatment episodes were associated with lower risk of relapse. Relapse risk increased as prior treatment exposure increased but prior treatment was associated with slightly lower total healthcare expenditures. These findings suggest that the effectiveness of OAT that has been demonstrated in clinical trials persists at the population level in a less controlled setting and that OAT is associated with lower total healthcare expenditures compared to other forms of behavioral treatment for patients with opioid addiction. Co-occurring other substance use and mental illness exert strong influences on cost and risk of relapse, suggesting that individuals with these conditions need more comprehensive treatment.

Keywords: Buprenorphine; Cost; Economic evaluation; Length of treatment; Medicaid; Methadone; Opioid addiction; Opioid agonists; Public policy; Substance abuse treatment; Treatment history.

Figure 1. Relapses during treatment among MassHealth members who received treatment for opioid addiction between 2003 – 2010¹

¹N = 18,866 episodes of buprenorphine treatment, 24,309 episodes of methadone treatment and 31,220 episodes of non-OAT behavioral health treatment in month 1. 33% of buprenorphine episodes, 52% of methadone episodes, and 12% of non-OAT treatment episodes lasted 12 months or more. 13% of buprenorphine treatment episodes, 27% of methadone episodes, and 1% of non-OAT treatment episodes lasted 24 months or longer.

Figure 2. Per member per month (PMPM) total expenditures during treatment for MassHealth members who received treatment for opioid addiction between 2003 – 2010¹

¹N = 18,866 episodes of buprenorphine treatment, 24,309 episodes of methadone treatment and 31,220 episodes of non-OAT behavioral health treatment in month 1. 33% of buprenorphine episodes, 52% of methadone episodes, and 12% of non-OAT behavioral health treatment episodes lasted 12 months or more. 13% of buprenorphine treatment episodes, 27% of methadone episodes, and 1% of non-OAT treatment episodes lasted 24 months or longer.