Sex, Race, and HIV Risk Disparities in Discontinuity of HIV Care After Antiretroviral Therapy Initiation in the United States and Canada

Abstract

Disruption of continuous retention in care (discontinuity) is associated with HIV disease progression. We examined sex, race, and HIV risk disparities in discontinuity after antiretroviral therapy (ART) initiation among patients in North America. Adults (≥18 years of age) initiating ART from 2000 to 2010 were included. Discontinuity was defined as first disruption of continuous retention (≥2 visits separated by >90 days in the calendar year). Relative hazard ratio (HR) and times from ART initiation until discontinuity by race, sex, and HIV risk were assessed by modeling of the cumulative incidence function (CIF) in the presence of the competing risk of death. Models were adjusted for cohort site, baseline age, and CD4⁺ cell count within 1 year before ART initiation; nadir CD4⁺ cell count after ART, but before a study event, was assessed as a mediator. Among 17,171 adults initiating ART, median follow-up time was 3.97 years, and 49% were observed to have ≥1 discontinuity of care. In adjusted regression models, the hazard of discontinuity for patients was lower for females versus males [HR: 0.84; 95% confidence interval (CI): 0.79-0.89] and higher for blacks versus nonblacks (HR: 1.17; 95% CI: 1.12-1.23) and persons with injection drug use (IDU) versus non-IDU risk (HR: 1.33; 95% CI: 1.25-1.41). Sex, racial, and HIV risk differences in clinical retention exist, even accounting for access to care and known competing risks for discontinuity. These results point to vulnerable populations at greatest risk for discontinuity in need of improved outreach to prevent disruptions of HIV care.

Keywords: NA-ACCORD; discontinuity; disparity; injection drug use; racial; retention; sex.

FIG. 1.

(a–c) Predicted CIF of discontinuity of retention and death before discontinuity, adjusted and weighted by available demographic, HIV risk, and site characteristics, stratified by (a) sex, (b) black race, and (c) IDU as HIV risk factor. (a) Adjusted and weighted CIFs, stratified by sex. (b) Adjusted and weighted CIFs, stratified by black race. (c) Adjusted and weighted CIFs, stratified by IDU as HIV risk factor. CIFs, cumulative incidence functions; IDU, injection drug use.

FIG. 2.

(a–c) Predicted CIF of discontinuity of retention, stratified and adjusted by scaled baseline age, estimated at quartiles of sample age distribution, by (a) sex, (b) black race, and (c) IDU as HIV risk factor. (a) Age-adjusted CIFs at quartiles of age distribution, stratified by female sex. (b) Age-adjusted CIFs at quartiles of age distribution, stratified by black race. (c) Age-adjusted CIFs at quartiles of age distribution, stratified by IDU as HIV risk factor. CIFs, cumulative incidence functions; IDU, injection drug use.

APPENDIX FIG. 1.

Plots of weighted Schoenfeld residuals and fitted values for over event times by (a) age, (b) female sex, (c) black race, and (d) IDU risk for the event of interest (discontinuity of retention). Residuals may be used to assess the proportional hazard subdistribution assumption by locally constant mean of the residuals across failure times; the heavy dotted red line is a locally weighted regression smoother.

APPENDIX FIG. 2.

Distribution of constructed IPW for the probability of (a) female sex, (b) black race, and (c) IDU risk, both untruncated and truncated at the 5^th and 95^th percentiles, including adjustment for clinic site, baseline age, baseline CD4+ count, nadir CD4+ count after ART initiation, and the other exposures not under estimation in that model.

APPENDIX FIG. 3.

Disparities in modeled cumulative incidence functions for first discontinuity of retention after ART initiation and re-entry to care after first discontinuity, treating death as a competing risk by (a) female sex, (b) black race, and (c) IDU risk.

APPENDIX FIG. 3.

Disparities in modeled cumulative incidence functions for first discontinuity of retention after ART initiation and re-entry to care after first discontinuity, treating death as a competing risk by (a) female sex, (b) black race, and (c) IDU risk.

APPENDIX FIG. 3.

Disparities in modeled cumulative incidence functions for first discontinuity of retention after ART initiation and re-entry to care after first discontinuity, treating death as a competing risk by (a) female sex, (b) black race, and (c) IDU risk.