The adherence threshold for combination antiretroviral therapy (cART) has historically been set at 95% or greater. We examined whether different levels of cART adherence (≥95% [optimal adherence], 90-94%, 80-89%, and <80%) were associated with different clinical outcomes (emergency department visits [ED visits] and duration of hospital admission) in a sample of older (50-64 years) persons living with HIV (PLWH). Medicaid data from 29 US states (n = 5177) were used for this study. cART adherence was measured and data regarding relevant covariates, such as race, sex, age, urbanicity, and comorbidity were obtained. Descriptive statistics were conducted to characterize study participants. We conducted univariate and multivariable regression analyses to evaluate the association between cART adherence and ED visits and duration of hospital admission while adjusting for covariates (race, sex, age, urbanicity, and comorbidity). Approximately 32% of all participants (n = 5177) reported optimal cART adherence (≥95%). After adjusting for covariates, only participants who reported <80% adherence were more likely to have an ED visit (adjusted odds ratio = 1.34, 95% CI = 1.08-1.48, p < .0001) and a longer duration of hospital admission (regression coefficient = 1.24, 95% CI = 0.53-1.96, p = .0007) when compared to participants who reported ≥95% adherence. There were no significant differences in likelihood of having an ED visit and longer duration of hospital admission between participants who reported ≥95% adherence and participants who reported 90-94% adherence and 80-89% adherence. Significant differences by covariates were observed. Adverse clinical outcomes were associated with low cART adherence (<80%) among older PLWH, though they did not differ between optimal and moderate cART adherence (90-94% and 80-89%). Although optimal cART adherence is an important goal, clinical outcomes in older PLWH may not differ between moderate and optimal cART adherence.
Keywords: HIV; adherence; antiretroviral therapy; clinical outcomes; older adults.