This study examined acute withdrawal symptoms and persistent withdrawal symptoms following four weeks of buprenorphine treatment in non-Hispanic Caucasian, African-American and Hispanic participants. We hypothesized that objective withdrawal symptoms would be higher in minority participants and subjective withdrawal symptoms would be higher in non-Hispanic Caucasians. The data do not support this hypothesis. During induction, Non-Hispanic Caucasians tended to have higher levels of both objective and subjective withdrawal symptoms, but the three groups had similar scores after completing the buprenorphine stabilization.
We also hypothesized that minority participants would report fewer adverse events than non-Hispanic Caucasians during buprenorphine administration. The data partially support this hypothesis with similar rates of adverse event reported in non-Hispanic Caucasian and Hispanic participants but lower rates of adverse events in African-Americans. The racial-ethnic differences in adverse events appear to be related to adverse events that were not study related. Thus, the data may support the idea suggested by (Kosten & Rayford, 1995
) that African-Americans may be hesitant to report adverse events. However, given the data, we cannot rule out the possibility that factors other than underreporting resulted in the between-group differences.
Some prior studies have reported higher attrition in minority participants during substance abuse treatment (Booth, et al., 1992
) (McCaul, et al., 2001
) (Mertens & Weisner, 2000
). We found similar rates of study attrition in the three groups. This finding is consistent with the report by (Kosten & Rayford, 1995
) that, as with the current report, examined attrition during buprenorphine therapy. Since buprenorphine effectively relieves uncomfortable withdrawal symptoms and decreases opioid craving, it is associated with relatively high treatment retention across racial and ethnic groups.
Opioid use differed between-groups in the 30 days prior to study entry. Minority participants reported more days of heroin use while non-Hispanic Caucasian participants reported more days of other opioid use (e.g. prescription opioids) than did minority participants. However, we did not find significant between-group differences in opioid use at the end of the buprenorphine stabilization period. About one third of participants in each group used opioids and two thirds used some drug following four weeks of buprenorphine administration. Similarly drug craving while higher in non-Hispanic Caucasians at induction, was similar following buprenorphine administration in the three groups. Thus, drug use was common during buprenorphine therapy but racial and ethnic differences were not found.
A major strength of the study is the large sample size that included many minority participants suggesting that negative findings are not due to Type II error. However, the study also has limitations. We omitted the “Other race” group which excluded a small number of participants. Hispanic, as defined for the analysis, includes both non-Hispanic Caucasian and African-American Hispanics. Mean withdrawal symptoms, both at induction and following buprenorphine, were low in all three groups. This is a secondary data analysis, so the study was not designed with the present analyses in mind. The study did not conduct Spanish-language withdrawal assessments which potentially led to reporting differences in some Hispanic participants who were not fluent in English.
In summary, racial/ethnic differences were found during a four week trial of buprenorphine administration. Non-Hispanic Caucasians tended to use more opioids other than heroin prior to study participation and had higher levels of withdrawal symptoms. However, drug use, craving, and withdrawal symptoms were similar in the three groups following buprenorphine administration. Thus, although the groups were different at induction, they showed similar symptomatology following the four week buprenorphine maintenance phase. African-Americans reported fewer adverse events during buprenorphine therapy suggesting either a more favorable course of treatment or reluctance to report adverse events to clinicians. Additional research is needed to identify factors responsible for racial differences in adverse event reporting during buprenorphine administration. The findings suggest an overall favorable treatment outcome for all three racial/ethnic groups during buprenorphine administration and suggest race/ethnicity may not play a major role in buprenorphine response and treatment retention.