Modelling adverse treatment outcomes of HIV-infected adolescents attending public-sector HIV clinics in Lusaka

Abstract

Background: In resource-limited setting, there is scarce evidence comparing antiretroviral therapy (ART) outcomes among HIV-infected adolescents to that of other age groups.

Methods and study design: We analysed data from 25 ART facilities in Lusaka District, comparing treatment-naïve ART-eligible young adolescents (10-14 years), older adolescents (15-19) and young adults (20-24 years) initiating first-line ART to those aged 24 years or older. The adjusted relative risk (RR) of failure to achieve an adequate CD4 response (defined as failure to increase CD4 count by ≥ 50 cells/mm³ at 6 months or by ≥ 100 cells/mm³) at 6 or 12 months after ART initiation was modelled using log-binomial regression. The effect of age group on mortality and loss to follow-up (LTFUP; ≥60 days since scheduled visit date) was estimated using adjusted Cox proportional hazards models, respectively. This was a routine retrospective design using program data.

Results: Of the 94,023 patients initiating ART from May 2004 to February 2011, 1303 (1.4%) were young adolescents, 1440 (1.5%) were older adolescents and 5825 (6.2%) were young adults. 85,455 (90.9%) were 24 years or older at the time of ART initiation. Compared with adults, both young adolescents (RR: 0.88, 95% confidence interval [CI]: 0.76-1.01 at 6 months and RR: 0.80, 95% CI: 0.69-0.93 at 12 months) and older adolescents (RR: 0.82, 95% CI: 0.71-0.95 at 6 months) were less likely to achieve adequate CD4 response. No evidence of a difference in mortality risk was observed among older adolescents (hazard ratio [HR] 1.20, 95% CI: 0.93-1.56) compared with adults; however, there was a reduced risk of mortality in young adolescents compared with adults (HR: 0.61, 95% CI: 0.40-0.92). Young adolescents were less likely to be LTFUP following ART initiation (HR: 0.74, 95% CI: 0.59-0.92), while older adolescents and young adults were reported to be more likely to drop out of care (HR: 1.54 95% CI: 1.33-1.78; HR: 1.51 95% CI: 1.40-1.63 respectively).

Conclusion: Older adolescents and young adults had poorer ART treatment outcomes, including failure to achieve adequate CD4 recovery and failure to remain in long-term care, when compared with adults. Interventions are necessary to help increase outcomes and retention in care.

Keywords: Adolescents; Adverse; HIV clinics; HIV-infected; Modelling; Outcomes; Public sector; Treatment.