Racial disparities in HIV virologic failure: do missed visits matter?

Abstract

Background: Racial/ethnic health care disparities are well described in people living with HIV/AIDS, although the processes underlying observed disparities are not well elucidated.

Methods: A retrospective analysis nested in the University of Alabama at Birmingham 1917 Clinic Cohort observational HIV study evaluated patients between August 2004 and January 2007. Factors associated with appointment nonadherence, a proportion of missed outpatient visits, were evaluated. Next, the role of appointment nonadherence in explaining the relationship between African American race and virologic failure (plasma HIV RNA >50 copies/mL) was examined using a staged multivariable modeling approach.

Results: Among 1221 participants, a broad distribution of appointment nonadherence was observed, with 40% of patients missing at least 1 in every 4 scheduled visits. The adjusted odds of appointment nonadherence were 1.85 times higher in African American patients compared with whites [95% confidence interval (CI) = 1.61 to 2.14]. Appointment nonadherence was associated with virologic failure (odds ratio = 1.78, 95% CI = 1.48 to 2.13) and partially mediated the relationship between African American race and virologic failure. African Americans had 1.56 times the adjusted odds of virologic failure (95% CI = 1.19 to 2.05), which declined to 1.30 (95% CI = 0.98 to 1.72) when controlling for appointment nonadherence, a hypothesized mediator.

Conclusions: Appointment nonadherence was more common in African American patients, associated with virologic failure, and seemed to explain part of observed racial disparities in virologic failure.

Figure 1

Basic mediation model employed in the evaluation of appointment non-adherence as a mediator of racial disparities in HIV virologic failure (plasma HIV RNA >50 copies/mL). According to this framework, a series of steps are required to conclude that mediation has occurred: (1) variations in the level of the independent variable significantly account for variations in the mediator (path a, Table 1), (2) variations in the level of the mediator significantly account for variations in the level of the dependent variable (path b, Table 3), (3) variations in the level of the independent variable significantly account for variations in the level of the dependent variable (path c, Table 3), and (4) the effect of the independent variable on the dependent variable (path c', Table 3,) is included in the equation.– Implicit in this framework is a temporal ordering whereby the potential mediator temporally follows the independent variable and temporally precedes the dependent variable. We believe the temporal relationship between variables is correctly defined in this study. For this study, the four steps are shown in both unadjusted analyses as well as when controlling for confounders, as displayed in the tables and described in the manuscript.

Figure 2

Distribution of appointment non-adherence among as measured by the missed visit proportion (MVP, 2a), and characteristics associated with MVP in bivariate analyses (1b) among 1,221 patients with at least 4 scheduled HIV primary care appointments over a ≥6 month time period at the UAB 1917 HIV/AIDS Clinic, August 2004 - January 2007. The median MVP and interquartile range is presented in Figure 2b and the non-parametric Kruskal-Wallis test was used to compare median MVP among study participants.