This study examined differential predictors of medication adherence among a cohort of HIV-positive drug using African American and Caucasian adults. Overall, African Americans demonstrated lower rates of medication adherence over the course of the study, which is consistent with other studies examining ethnic differences in HIV medication adherence.55–57
Results of previous studies assessing racial differences in HIV medication adherence have focused on socioeconomic factors that may moderate this relationship. However, there is more recent evidence to suggest that these factors alone do not eliminate disparities between racial groups on medication adherence.58
Hence, research efforts have been directed toward the role of the patient-provider relationship in studies of medication adherence among ethnic minorities.
Our sample of African Americans and Caucasians reported receiving similar types of health care, regimen complexity, and SES. As such, we are less concerned that the racial group differences observed in medication adherence resulted from solely socioeconomic differences. A major strength of the current study was repeated use of objective measures of medication adherence use over a period of 6 months.
Considering that we found ethnic differences in current drug use, we conducted analyses with and without current drug users and African Americans still continued to demonstrate lower adherence rates (70% versus 80%). Therefore, the racial differences observed in the current study are less likely attributable to disproportionate number of African Americans drug users.
Duration of drug use was strongly predictive of medication adherence for both African American and Caucasian patients, which is consistent with the current literature on substance abuse on medication adherence among ethnically diverse samples. Considering that a majority of our sample tested positive for both cocaine and marijuana, we did not treat type of drug as a covariate in the regression analyses.
Provider satisfaction and treatment-specific social support
Satisfaction with health care provider emerged as a particularly strong indicator of medication adherence for African Americans, in particular and remained significant after controlling for other critical variables such as current drug use. This is consistent with other studies documenting racial/ethnic group differences in medication adherence as a result of the patient-provider relationship. Of particular interest is that despite both racial groups reporting similar levels of satisfaction with health care provider, it was only predictive of adherence for African Americans, suggesting that the patient–provider relationship may be a unique influence for African Americans. Medication adherence typically involves a decision-making process (weighing the costs and benefits of taking medication) and may reflect knowledge, attitudes, or lay health beliefs that influence medication decisions, resulting in skipping or altering doses. Interpersonal aspects of the patient–provider relationship may influence attitudes toward taking medications, health beliefs related to HIV, and perceived benefits of medical outcomes.59
It is well-documented that individuals' beliefs about their susceptibility to illness and HIV and medication efficacy play a crucial role in adherence. As mentioned previously, one critical aspect related to racial disparities in HIV medication adherence is trust. Racial differences in mistrust are believed to stem from perceived and actual racial discrimination in prior interactions with health care providers,60
racial discordance with health care providers,61
and HIV conspiracy beliefs.58
Therefore, given that the quality of the patient–provider relationship is predictive of medication adherence, providers can play an important role in addressing the patients' treatment-related concerns, dispelling inaccurate information, and addressing issues of trust; thereby, attenuating some of the negative connotations that African Americans associate with taking medications. Overall, increasing patient satisfaction with provider may help to reduce racial disparities in cART adherence, and ultimately improve long-term survival.
The current study did not track provider race or account for whether patient satisfaction with provider increased in the presence of patient–provider racial concordance. Future researchers in this area may want to examine specific factors involved in how patient satisfaction with provider affects medication adherence among African American HIV-positive individuals, including racial concordance, patient–provider communication, distrust of health care providers versus distrust of health care institutions and other specific health-related beliefs held by African American patients.
Interestingly, treatment-specific social support was significantly predictive of medication adherence for Caucasians, but not for African Americans. While this seems counterintuitive, it may actually reflect the fears of stigmatization within the African American community.62
African Americans carry the additional burden of dealing with the negative effects associated with the stigma of HIV, which may become particularly salient among larger support networks. For example, in a study of African American cancer survivors, although participants reported having support networks, when support was not forthcoming, participants feared that it was a result of negative beliefs.63
It is important to note that we only assessed whether our participants perceived support in relation to their HIV status and treatment. We did not assess the quality of support or assistance that they actually received, or if support was forthcoming. Therefore, it is possible that the support networks among our African American sample differed from our Caucasian sample in terms of stigma, distrust toward health care in general, and literacy. This is a complex topic that warrants further study.
Our results suggest that the effects of depression on medication adherence may vary by ethnicity as well, with depression impacting medication adherence among Caucasians. We find this of particular interest given that both groups reported equal levels of depressive symptoms. In review of several studies on depression and medication adherence, the majority of those reporting significant relationships studied predominantly Caucasian samples,64
whereas several studies that were unable to document relationships reported predominantly African American samples.39
In studies using multivariate analyses, the effects of depression no longer remained statistically significant once other factors were considered, such as demographic factors.19
Future studies are needed to confirm whether there is indeed a differential effect of depression on medication adherence based on ethnicity, or whether psychosocial factors (e.g., spirituality) may attenuate the deleterious effects of depression on medication adherence for African Americans.
Literacy and cognition
Contrary to expectations, cognition and reading ability were not significantly predictive of medication adherence. The reasons for this are not entirely clear, but may be due to our sample's overall performance on both cognitive and literacy tests. Although there were ethnic differences in performance, both groups performed in the average range on all measures, suggesting adequate literacy levels and intact cognition. Perhaps once literacy and cognitive ability fall below a certain threshold, it plays a more pertinent role in medication adherence.
It is important to highlight the overall low adherence rates across both ethnic groups over the course of this study. The highest adherence rate documented (i.e., 78%) among our Caucasian participants is still considerably low. While more recent research has demonstrated that adherence rates of approximately 75% to NNRTI-based regimens are associated with maintained virologic suppression, most of our participants' adherence rates were well below this cutoff. While we recognize that unequal sample sizes between our ethnic groups is a considerable limitation to the current study, the distribution of African Americans and Caucasians in our study reflect that of the HIV/AIDS population, where blacks are disproportionately infected. Considering that our predictor variables of interest did not violate statistical assumptions, and the effect sizes for our predictor variables were notably different between groups, we are less concerned that the lack of statistical power in the Caucasian group suppressed the predictive power of the variables under study.
Another limitation to the current study is that our sample in general was of low socioeconomic status and current drug users. Therefore, we must caution the reader that these results are only generalizable to HIV-positive individuals from lower SES backgrounds. Future research looking at racial/ethnic differences in medication adherence should include individuals from higher SES backgrounds to further tease apart factors that may impact African Americans from various SES backgrounds.