We recruited a diverse sample (50% White, 20% Hispanic, and 10% Black), of whom 43% were HIV-positive (Table 1). Baseline demographic characteristics were similarly distributed in both arms with the exception of income (P = 0.01). Fifty-three percent reported using meth between 3 and 7 days/week and 53% of participants reported using meth with sex at least 50% of the time. The most common route of meth administration was smoking (87%), followed by injecting (50%) and snorting (47%). A minority (40%) of participants had previously sought substance use treatment or self-help programs for meth use. Mean severity of dependence scale score was high (5.9 +/−3.5) SCID score. Symptoms of depression were elevated (mean CESD score 20.1 +/−11.5) and 20 participants (67%) had CES-D scores at least 16 at baseline. At study completion, mean changes in CESD were +2.9 +/− 10.1 and −1.9 +/− 13.3 in the placebo and bupropion arms, respectively. These differences were not statistically significant by Wilcoxon rank-sum test (P value = 0.21). Forty-seven percent reported having health insurance and 60% reported having a regular healthcare provider. The most commonly used other substances were marijuana (63% of participants), poppers (43% of participants), and club drugs including GHB, ketamine and ecstasy/MDMA (40% of participants) (data not shown).
Twenty-seven participants (90%) completed the trial with no significant differences by treatment assignment. Overall, 89% of monthly follow-up ACASI risk assessments were completed (bupropion 87%, placebo 93%; P = 0.38), 81% of weekly follow-up study visits were attended (bupropion 80%, placebo 81%; P = 0.96), and 81% of all scheduled weekly urine samples were collected (bupropion 80%, placebo 81%; P = 0.96).
Adherence to study drug as measured by MEMS caps was 60% (59% bupropion, 62% placebo; P = 0.98), whereas adherence by self-report was 81% (85% bupropion, 75% placebo; P = 0.21). The correlation between adherence as measured by MEMS and by self-report was 54%. The most common reasons given for nonadherence included ‘simply forgot’ (18%), ‘busy with other things’ (18%), ‘away from home’ (16%), ‘change in daily routine’ (16%), ‘slept through dose’ (10%) and ‘high on meth’ (9%). Three participants in each group, including the three who did not complete the trial, had at least a week-long medication discontinuation prior to study completion (P = 0.37). Time to the first week-long medication discontinuation did not differ by treatment assignment (P = 0.48 by log-rank test).
At randomization, 73% of participants had meth-metabolite-positive urines (bupropion 65%, placebo 90%; P = 0.21). The proportion of meth-metabolite positive urines at follow-up visits decreased in both groups (Table 2). After accounting for the initial difference in meth-metabolite-positive urines, using a normal-logistic model, the reductions were similar in the two groups (P = 0.63). Results were similar if week 1 meth-metabolite urine results were included and in an analysis imputing positive results for missing urine meth-metabolite results.
At baseline, the 20 participants in the bupropion group had a median of 3.5 male sexual partners in the past 4 weeks, whereas the 10 participants in the placebo group had a median of 13.5 partners (P = 0.11 by Wilcoxon test; Table 3). After adjusting for the baseline difference, the declines were similar (P = 0.46). The number of male partners with whom meth was used also declined during the trial. After adjusting for the baseline difference, the declines in male partners with whom meth was used were again similar (P = 0.71). Comparable declines across both groups were also seen in unprotected insertive (P = 0.90) and receptive (P = 0.62) anal sex with serodiscordant partners. The declines in prevalence of unprotected serodiscordant anal sex were similar in both groups (P = 0.09).
There were no serious adverse events in the study. The most common adverse events were unrelated to study drug and were mild to moderate (grade 1 or 2) liver function test elevations, dermatologic conditions (grade 1 or 2), or electrolyte abnormalities (grade 1). There was one grade 3 ALT elevation. There were no significant differences in adverse events by treatment assignment (P = 0.11). One participant in the bupropion arm was diagnosed with HIV and rectal gonorrhea. Another participant in the bupropion arm reported agitation which resolved after study drug dose reduction.
At study completion, 96% of volunteers were highly satisfied or satisfied with study participation, whereas 11% (3/2-7) found study participation very or somewhat difficult. Ninety-three percent (25/27) of participants completing the study reported that they would be likely to participate in a similar study in the future. Participants at study completion were asked to guess their treatment assignment. In the placebo group, five of nine or 56% guessed they were on placebo. In the bupropion group, nine of 18 (50%) guessed correctly. Treatment guessing accuracy between two groups did not differ significantly by Fisher's exact test (P = 1.00).
In this randomized, double-blind, placebo-controlled trial, we demonstrated that it was feasible to enroll and retain actively using, high-risk, meth-dependent MSM in a pharmacologic intervention trial, outside of a drug treatment program, with excellent rates of participation in study visits, procedures, and follow-up evaluations. Given the high rates of meth use among MSM, the associations among meth use, sexual risk behavior and HIV, and the fact that most meth-dependent MSM have not accessed current treatment options, it was important to demonstrate that high-risk MSM are willing to participate in pharmacologic studies for meth treatment. We found a high level of enthusiasm for our study as indicated by high participation rates and interest in joining similar studies in the future. Retention rates were substantially higher than in the two previously reported studies of bupropion for meth dependence [68,69].
Stimulant use is associated with lower medication adherence, including to HIV medications among HIV-positive meth users [17,85–88]. Our adherence rates were comparable to adherence rates among drug users in other studies [86,88]; however, our rates were lower than reported in the previous bupropion studies [68,69]. We used the more rigorous MEMS measure, as is common in antiretroviral medication adherence trials [70,87]. Our findings that self-reported adherence (81%) was higher than MEMS-measured adherence (60%) is consistent with the evidence that self-report tends to overestimate antiretroviral adherence .
The study has limitations. We had a relatively low phone prescreen to randomization ratio (9%) which should be considered when interpreting conclusions regarding feasibility. Among those assessed in person for eligibility, the randomization ratio was much higher (56%). This was a phase II pilot study and was not powered to assess the efficacy of bupropion and thus our comparisons by treatment assignment should be interpreted with this limitation in mind. Also, compared with other drug treatment studies, often done in drug-treatment centers, our once-weekly study visit schedule may be considered ‘low intensity.’ More intensive study visit requirements would have likely reduced our relatively high participation rates.
Despite the above limitations, our study demonstrates that it is feasible to enroll actively using, meth-dependent MSM in a pharmacologic trial with excellent attendance, compliance with study activities, and retention. Results of participants' assessment of whether they took bupropion or placebo show no compelling evidence of unblinding. Our modest adherence rates suggest that upcoming studies of pharmacologic interventions for meth dependence should be accompanied by adherence support measures that address the complex needs of this population. Sexual risk behavior declined during participation in this pharmacologic and substance use counseling intervention, suggesting potential of drug use reduction as a key part of HIV prevention interventions that target groups at highest risk. We must intensify our efforts to identify potential pharmacologic therapies for meth dependence, and to enroll high-risk populations, both to reduce meth-related morbidity and to further prevent HIV acquisition and transmission.
M.D. drafted the manuscript, assisted with the analysis, and primarily interpreted the data.
D.M.S. assisted in the conception and design of the study, acquisition, analysis and interpretation of data, and revising the manuscript for important intellectual content.
T.M. assisted in the conception and design of the study, acquisition of the data, and revising the manuscript for important intellectual content.
G.-M.S. assisted in the analysis and interpretation of data, and revising the manuscript for important intellectual content.
P.L.C. assisted in the analysis and interpretation of data, and revising the manuscript for important intellectual content.
E.V. assisted in the design of the study, analysis and interpretation of data, critical revision of the manuscript for important intellectual content, and the statistical analysis.
S.S. assisted in the conception and design of the study, interpretation of data, and critical revision of the manuscript for important intellectual content.
G.N.C. conceived and designed the current study, assisted with analysis, interpreted the data, and in the critical revision of the manuscript for important intellectual content. He also obtained funding and material support and provided supervision.
The funder did not have any role in the design and conduct of the study; collection, management, analysis or interpretation of the data; or preparation, review or approval of the manuscript.
All authors had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
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