Predictors of Medication Adherence in an AIDS Clinical Trial: Patient and Clinician Perceptions

In phase I and phase II trials with participants who have HIV, close monitoring of medication adherence is usually part of the study design. In phase III trials, however, medication and appointment adherence may not be as tightly monitored or reported, and thus the extent of nonadherence is often unaccounted for in the analyses and interpretations of these clinical trials (Boudes, 1998; Freedman, 1990). Such distinctions are relevant to social workers, who either help researchers design clinical trims or help clients enroll in them. Social workers are reservoirs of information, conduits of retention, and problem solvers who facilitate the doctor-patient relationship when clinical trial management is involved (Cox, 2002; Williams, 1999). As a result of medical advances in the management of HIV, individuals who are infected are required to adhere to complicated regimens involving three or more medications, some with multiple doses per day. This contributes to the likelihood that patients will have difficulty following their regimens. Failure to take medications properly can result in the development of HIV resistance, posing a threat to the individual infected with HIV and to those to whom a resistant virus could be transmitted. Thus, it is imperative to elucidate the factors affecting medication adherence of patients who are infected with HIV; therefore, a major thrust of the present study was to reveal these medication compliance predictors. The majority of studies evaluating medication adherence in patients with chronic illnesses such as hypertension, epilepsy, heart disease, or diabetes have demonstrated adherence rates of 50 percent or less among patients treated for these incurable but not necessarily fatal diseases (Kravitz et al., 1993; Sackett & Snow, 1979). Several reviews have provided extensive summaries of the existing general an d HIV-related adherence research literature (Besch, 1995; Ickovis & Weisler, 1997; O'Brien, Petrie, & Raeburn, 1992). Common nonadherent behaviors include discontinuing treatment prematurely, taking medications incorrectly, taking drug holidays, using treatments or substances not prescribed, and not attending appointments. Low adherence levels in a clinical trial may result in erroneous conclusions if participant adherence is not taken into account when the results are interpreted (Horowitz & Horowitz, 1993). At the time of the design of the present adherence study--a companion to a clinical trial being conducted by a federally funded, community-based program--the only published study designed to assess the primary sociocultural determinants of HIV patient adherence within an experimental phase III research drug study had been conducted by Morse et al. (1991).The Morse et al. study used nurses' ratings of patients' medication adherence for ACTG 019, a double-blind, placebo-controlled trial of zidovudine in asymptomatic individuals with HIV. This study of mostly gay white men found that the more adherent patients lived farther from their study site; were less concerned with confidentiality; and were more likely to have emotional, economic, and social support. The present adherence study's parent clinical trials program developed an observational adherence protocol to systematically evaluate the differential patterns of adherence with taking two different regimens of Bactrim to prevent an often-fatal HIV-related opportunistic infection. For five years, the adherence study evaluated patient and clinician perceptions of adherence with protocol-specific pill-taking regimens and study visit attendance in relationship to psychological variables and health belief model (HBM) premises. METHOD Study Population To be eligible for the adherence study, patients had to be enrolled in the Pneumocystis carinii pneumoni (PCP) prophylaxis trial (PCP-TMS study) (El-Sadr et al., 1999) and be able to read English or Spanish. …