Background: Little is known about the effect of social deprivation on HIV treatment outcomes in the UK, a setting with universal free access to health care. We assessed the association of socio-economic factors with subsequent virological rebound among individuals with initial virological suppression on ART.
Methods: ASTRA is a questionnaire study of 3258 HIV-diagnosed individuals from 8 UK HIV clinics in 2011/2012, with longitudinal linkage to clinical records for consenting participants (92%) at 4 clinics. We included those who had received ART for >6 months, had viral load (VL)≤50 c/mL at the time of the questionnaire (baseline) and with ≥1 subsequent VL measure. Individuals were followed from baseline until virological rebound (1st VL>200 c/mL) or last available VL (latest April 2014). Self-reported non-adherence was defined as the number of times ≥2 consecutive days of ART was missed in the 3 months prior to baseline (0; 1; ≥2). Follow-up was not censored if ART was interrupted. We assessed the association of each socio-economic factor (financial hardship, employment, housing, education, time in UK, English reading ability, supportive network) with virological rebound in a separate Cox regression model, adjusted for (i) demographic factors (gender/sexual orientation; ethnicity; age; clinic); (ii) demographic factors and baseline non-adherence. Sensitivity analyses considered rebound as 2 consecutive VL>200 c/mL.
Results: 1490 people were followed for 2710 person-years [median 3 (range 1-17) VL measures per person]. 65 (4%) people experienced virological rebound (rate 2.4/100 pyrs; 95% CI 1.8-3.0). Kaplan-Meier percentages with rebound by 12 and 24 months were 2.0% (95% CI 1.3-2.8) and 4.8% (3.5-6.0). After adjustment for demographic factors, increasing financial hardship, non-employment, non-homeownership, non-university education and lack of supportive network were associated with higher risk of rebound (Table). Although further adjustment for baseline non-adherence did not fully explain the associations, they were attenuated (Table). Sensitivity analysis results were consistent (37 rebounds).
Conclusions: Even in this setting with free access to treatment and low rates of virological rebound, we observed a substantial impact of social deprivation on increased risk of rebound among people with initial virological suppression. These associations are likely mediated through non-adherence. Targeted adherence interventions and increased social support for those most at risk should be considered.
Table: Association between socio-economic factors and virological rebound
(x each socio-economic factor considered in a separate model for all results;* gender/sexual orientation, ethnicity, age and clinic; # self-reported number of times ≥2 consecutive days of ART missed in 3 months prior to baseline (0; 1; ≥2); ~ per 100 person-years; ^ test for trend; aHR=adjusted Hazard Ratio)