Effect of persistency of first-line HIV antiretroviral therapy on clinical outcomes.

Persistency is the time from initiation to discontinuation of therapy. Previous research has described factors that affect the persistency of initial antiretroviral therapy (ART); however, the impact of persistency on clinical outcomes is unknown. A retrospective study was conducted of treatment-naive HIV patients initiating ART between January 1, 2000 and December 31, 2010 at an academic medical center. Descriptive statistics and Cox proportional hazards regression models with persistency as a time-varying covariate were fit for (1) immunologic failure (subsequent CD4 lower than initial CD4); (2) development of an opportunistic infection (OI) or malignancy; and (3) mortality. Analyses were repeated with an interaction term of persistency (per 180 days) and time (before and after 1 year of ART). Among 879 patients who started ART, the mean age was 38 years (±10) and most patients were racial/ethnic minority (59%), males (80%), and with baseline CD4 <200 cells/mm(3) (52%). There were 100 deaths, 94 OIs/malignancy, and 183 immunologic failures; the mean persistency=723 days. In multivariable modeling, increased persistency decreased the overall and long-term hazard for immunologic failure (0.84 per 180 additional days; 0.70-1.00; 0.045). Increased persistency exhibited a potential trend toward decreased hazard for the occurrence of OI/malignancy (0.91; 0.80-1.03; 0.124) overall and after 1 year. Persistency exhibited a trend toward less risk of mortality in the first year of ART (0.42; 0.17-1.06; 0.067). In this study of the relationship between initial ART persistency and clinical outcomes, increased persistency was associated with a decreased hazard for the development of immunologic failure, a trend toward a decreased hazard for OI/malignancy, and a trend toward a decreased risk of first year mortality. Given these findings, the relationship between persistency and clinical outcomes merits further study.