Initial abstinence status and contingency management treatment outcomes: does race matter?

Cocaine use disorders are one of the most severe and destabilizing problems in segments of the African American community (Kramer, Bell-Tolliver, Tripathi, & Booth, 2011; Peters, Williams, Ross, Atkinson, & Yacoubain, 2007). Deleterious health effects of cocaine use, such as HIV (Tobin, German, Spikes, Patterson, & Latkin, 2011), coronary stenosis (Lai et al., 2012) and intracerebral hemorrhages (Martin-Schild et al. 2010; Qureshi et al., 2001), are particularly pronounced in African Americans, leading to high rates of morbidity and mortality (Bland et al., 2012; Kalokhe et al., 2012). Cocaine use is also strongly related to homicide (Chauhan et al., 2011) and incarceration (Hartley & Miller, 2010), sexual risk-taking behaviors (Gullette, Booth, Wright, Montgomery, & Stewart, 2013; Maranda, Han, & Rainone, 2004) and relationship conflicts (Golub, Dunlap, & Benoit, 2010) among African Americans. These negative cocaine-related consequences highlight the need for effective treatment for this population. However, a growing body of literature demonstrates that African Americans are more likely to drop out of substance abuse treatment (e.g., Campbell, Weisner, & Sterling, 2006; Davis & Ancis, 2012) and less likely to reduce drug use during treatment (Montgomery, Burlew, Kosinski, & Forcehimes, 2011; Montgomery, Petry, & Carroll, 2012) than their White counterparts. Contingency management (CM) is a behavioral intervention that uses tangible reinforcers to promote abstinence from drugs. In exchange for negative urine samples, patients earn vouchers worth escalating monetary amounts (Higgins, Badger, & Budney, 2000; Higgins et al., 2007) or chances to win $1-$100 prizes (Petry, Alessi, Hanson, & Sierra, 2007; Petry, Alessi, & Ledgerwood, 2012; Petry, Alessi, Marx, Austin, & Tardif, 2005). In a meta-analysis of psychosocial treatments for substance use disorders, CM had the largest effect size in reducing drug use (Dutra et al., 2008), and it consistently reduces cocaine use (Farronato, Dursteler-Macfarland, Wiesbeck, & Petitjean, 2013; Lussier, Heil, Mongeon, Badger, & Higgins, 2006). Several studies have examined effects of patient factors, such as age (Weiss & Petry, 2011; 2013), socioeconomic status (Secades-Villa et al., 2013), and income (Rash, Olmstead, & Petry, 2009; Rash, Andrade, & Petry, 2013), as influences on CM outcomes. These studies generally find few patient factors reliably impact response. However, one patient factor—baseline severity of drug use—has consistently been related to response to treatment in general (Alterman, McKay, Mulvaney, & McLellan, 1996) and CM (McLellan et al., 1994) in particular. Presence of a drug-negative urine sample at treatment initiation is associated with lower drug use severity and improved outcomes (Ahmadi, et al., 2009; Preston et al., 1998; Silverman et al., 1998). Further, CM is more efficacious in patients who begin outpatient treatment with a drug-negative sample than those who initiate treatment with a drug-positive sample (Stitzer et al., 2007). Race is another patient factor that has been show to influence treatment outcomes generally (Guerrero et al., 2013; Hunter, Paddock, Zhou, Watkins, & Hepner, 2013). To our knowledge, only four studies have examined CM outcomes in African American patients in outpatient settings (Barry, Sullivan & Petry 2009; Bride & Humble, 2008; McKay et al., 2010; Montgomery et al., 2012). Bride and Humble (2008) found that CM was effective in increasing outpatient substance abuse treatment attendance and completion rates among African-American women on welfare. Barry et al. (2009) demonstrated comparable efficacy of CM in reducing cocaine use among African American, Hispanic and White methadone maintained clients. McKay et al. (2010) found that CM was more effective than cognitive-behavioral relapse prevention in producing lower rates of cocaine positive urine samples and self-reported cocaine use among a predominately African American cocaine-dependent sample who had achieved initial engagement in intensive outpatient (IOP) treatment. However, a recent study by Montgomery et al. (2012) revealed that African American marijuana-dependent young adults receiving outpatient treatment did not derive benefits from CM, while CM was effective in reducing the proportion of marijuana positive samples among their White counterparts. Although these studies assessed outcomes among racially diverse populations, one was limited to women (Bride & Humble, 2008), one to court-referred young adults (Montgomery et al., 2012), another to adults who successfully completed IOP treatment (Mckay et al., 2010), and the fourth (Barry et al. 2009) to methadone maintenance patients, who have severe drug use problems and for whom treatment is a lifelong recommendation. Effects of race on response to CM have not been systematically evaluated in standard, outpatient psychosocial treatment facilities. Further, the small number of African Americans participating in some of the above studies limits the power to detect between group differences and generalization of the findings. The present study was designed to address these gaps and determine if, in a larger sample, African American and White cocaine abusing patients responded similarly to CM, and if response to CM between racial groups is affected by initial abstinence status. Given past literature (Montgomery et al., 2011; Montgomery et al., 2012; Milligan et al., 2004; Stitzer et al., 2010), we hypothesized that African American patients may disengage from treatment more rapidly and have worse drug use outcomes, regardless of treatment condition and baseline drug use status. We also expected that baseline drug use status would impact treatment outcomes overall, with those with a positive sample at treatment initiation remaining in treatment for shorter periods and achieving less abstinence. CM was expected to positively impact outcomes, but whether effects varied by race and baseline drug use status was examined. Both short-term (during treatment) and long-term follow-up effects were evaluated.