Role of state policies in the adoption of naltrexone for substance abuse treatment.

The development of pharmaceutical agents to quell cravings has the potential to expand access to substance abuse treatment and improve treatment quality for alcohol and drug-dependent individuals. An estimated 19 million individuals (approximately 8 percent of the U.S. population) meet standard diagnostic criteria for an alcohol use disorder, but just 2.4 million seek treatment and only 139,000 receive medication to treat the problem (Medical News Today 2005; McLellan 2006). Because public programs account for the majority of spending on substance abuse treatment through Medicaid and block grants, the incentives these policies create are central to understanding pharmaceutical adoption decisions and usage rates. State governments have much at stake in designing effective incentives and removing barriers to the use of proven treatments. The direct and indirect costs of alcoholism cost approximately $185 billion per year. On average, states spend about $1 of every $7 of total spending on programs related to substance abuse and its consequences (National Center on Addiction and Substance Abuse 2001). Yet typically, <5 percent of these expenditures is spent on prevention, treatment, and research; the remainder is spent primarily on incarceration, hospital care, child neglect, poverty, and other social problems associated with substance abuse. Substance abuse treatment is provided primarily through specialty sector programs that are largely funded through federal block grants to states and beget myriad reimbursement arrangements. As health care costs have risen, the efforts of governments and employers to reduce costs through managed care have disproportionately fallen on addiction treatment (McLellan 2006). States have responded to increasing drug costs by adopting policies that limit pharmaceutical use and increase cost sharing for Medicaid enrollees. In the face of declining overall budgets, both the number of substance abuse treatment programs and the number of patients have dwindled (Soumerai 2004; McLellan 2006). Our research focuses on a pharmaceutical agent used in addiction treatment: naltrexone,1 which was approved in 1994 by the Food and Drug Administration as an adjunct to the treatment of alcohol dependence. Naltrexone blocks alcohol-induced stimulation of endogenous opioids, dulling the “high” feeling produced by alcohol. Evidence from clinical trials has confirmed its effectiveness in reducing alcohol abuse, lowering relapse rates, and improving treatment outcomes (Fuller and Gordis 2001; Morris et al. 2001; Kosten and O'Connor 2003; Anton et al. 2006; McLellan 2006). For example, Morris et al. (2001) reported that the mean time to relapse drinking was 6.7 weeks for patients receiving naltrexone, compared with 4.2 weeks for those receiving a placebo. Another study (Anton et al. 2006) found that among patients receiving medical management (but no cognitive behavior intervention), patients receiving naltrexone were abstinent 80.6 percent of the days in the 16-week treatment program, compared with an abstinence rate of 75.1 percent for those receiving a placebo (an effect size of 0.22). Importantly, naltrexone may be as effective when prescribed by physicians in primary care settings as in specialized treatment settings (O'Malley et al. 2003), and a recent randomized-controlled trial (Anton et al. 2006) found that naltrexone was equally effective alone (in the presence of medical management) as combined with behavioral therapies. An estimated 16–30 percent of primary care patients are problem drinkers (O'Malley et al. 2003); thus, the ability to expand treatment options and increase access to treatment through primary care providers is a potential benefit of naltrexone. As a generic drug with no close therapeutic substitutes in the treatment of alcohol dependency, naltrexone should be a widely available treatment option. The formularies of most public and private sector managed care organizations (MCOs) provide blanket coverage of generics.2 Yet estimates of naltrexone prescription rates are low, ranging from 2 to 13 percent among the alcohol dependent in specialty treatment settings. Even lower use rates are exhibited among the wider population of adults meeting criteria for alcohol abuse or dependence (Mark et al. 2003; Harris and Thomas 2004). The decision to prescribe naltrexone is ultimately made by a physician or other medical staff in treatment facilities with prescribing privileges. Although the supply of naltrexone may be relatively unrestricted, these treatment decisions may also be influenced by demand-side strategies for limiting use such as copayments, quantity limits, or prior authorization. Both researchers and treatment professionals have pointed to the central role that these policies likely play in the decisions of treatment facilities to integrate naltrexone into treatment programs or individual physicians to prescribe naltrexone. The National Academy of Sciences Committee on Immunotherapies and Sustained-Release Formulations for Treating Drug Addiction (Harwood and Myers 2004) advised that in addition to clinicians' acceptance of new pharmacotherapies in either specialty or primary care settings, these pharmaceutical agents will only be effective to the extent that “their use is facilitated through adequate financing, organizational structures, and community support.” With data assembled on state policies, linked with data from the National Survey of Substance Abuse Treatment Services (N-SSATS), we test hypotheses about the relationships of state- and facility-level factors to naltrexone adoption. We focus on state strategies aimed at limiting the costs or use of pharmacotherapies and other treatment services.