Introduction: In the United Kingdom, rates of virological suppression on antiretroviral therapy (ART) are very high, but there remain a small but significant number of people on ART with detectable viraemia. The impact of socio-economic factors on virological suppression has been little studied.
Materials and methods: We used data from ASTRA, a cross-sectional, questionnaire study of >3000 individuals from 8 clinics in the United Kingdom in 2011-2012, linked to clinical records to address this question. Included participants had received ART for >6 months with a recorded current viral load (VL) (latest at the time of questionnaire). Participants provided data on demographic factors: gender, sexual orientation, ethnicity and age; and socio-economic factors: UK birth/English reading ability, employment, housing, education and financial hardship. To assess non-adherence, participants were asked if in the past 3 months, they had missed ART for ≥2 days at a time. Virological suppression was defined as VL≤50 cps/mL. For each socio-economic factor, we calculated prevalence ratios using modified Poisson regression, first adjusting for demographic factors, then also for non-adherence.
Results: A total of 2445 people fulfilled the inclusion criteria (80% male, 69% MSM, median age: 46 years, median CD4 count: 556 cells/mm(3)); 10% (234/2445) had VL>50 cps/mL. After adjusting for demographic factors, non-fluent English, not being employed, not home owning, education below university level and increasing financial hardship were each associated with higher prevalence of VL>50 cps/mL. Additional adjustment for non-adherence largely attenuated each association, but did not fully explain them (see Table 1). After adjustment for non-adherence and demographic factors, younger age was also associated with VL>50 cps/mL: for each additional 10 years an individual was 0.80 (95% CI 0.70-0.92) times as likely to have VL>50 cps/mL (p=0.0019). Adjusted prevalence ratios for VL>50cps/mL were 0.91 (0.62-1.34) for women and 1.25 (0.85-1.84) for non-MSM men versus MSM, and 1.29 (0.92-1.80) for white versus non-white people.
Conclusions: Among people on ART in the United Kingdom, the proportion with detectable VL is low. Poorer socio-economic status is associated with increased probability of virological non-suppression. It is likely that much of this association is mediated through difficulties in taking ART. Emphasis should be put on aiding the adherence of people in these higher risk groups.