Suppressed or unsuppressed HIV in adults on antiretroviral therapy in Zambia: who is at risk?

Abstract

Purpose of the studyTo determine factors associated with suppressed or unsuppressed HIV in adults receiving combination antiretroviral therapy (cART) in Zambia.MethodsThis was a cross-sectional study conducted between August 2008 and October 2009 in 16 Zambian communities nested within the ZAMSTAR trial [1]. Adult TB cases identified at a TB clinic of each community and their adult household members were invited to participate in the study. A structured interview was used to obtain information on the participants’ social, demographic and clinical characteristics. Socio-economic position (SEP) was measured using household wealth indices used in demographic health surveys. Principal component analysis was used to determine the cut-off for high (wealthy) and low (poor) SEP. Depression symptoms were measured using the Center for Epidemiological Studies Depression scale (CES-D). A cut-off of≥22 on the CES-D was used to define current depression [2]. Participants were included in this analysis if they were found to be receiving cART for>90 days at the time of the interview. The outcome was HIV suppression (viral load≤300 copies/ml). In both univariable and multivariable analyses, log Poisson regression models with robust standard errors adjusted for the 16 communities were used to calculate the risk ratios (RR), 95% confidence intervals (CI) and p-values of factors associated with HIV suppression. In multivariable analysis, each variable was independently assessed for its association with HIV suppression while minimally adjusting for a priori confounders (age, gender and education level).Summary of resultsThere were 520 patients receiving cART for>90 days. The median age was 35 years (inter-quartile range: 31–41) and 328/520 (63.1%) were married (Table).HIV suppressionHIV suppression vs. no suppression n=520YesNoUnadjustedAdjusted N (column %)N (row %)N (row %)RR (95% CI)p-valueRR (95% CI)p-value Age group, years 16 to 2547 (9.0)39 (83.0)8 (17.0)126 to 35220 (42.3)183 (83.2)37 (16.8)1.00 (0.85–1.18)0.97636 to 45187 (36.0)162 (86.6)25 (13.4)1.04 (0.91–1.20)0.541Above 4566 (12.7)58 (87.9)8 (12.1)1.06 (0.90–1.25)0.503 Gender Men204 (39.2)169 (82.8)35 (17.2)1Women316 (60.8)273 (86.4)43 (13.6)1.04 (0.97–1.12)0.261 Education level None/Primary241 (46.3)200 (83.0)41 (17.0)1Secondary279 (53.7)242 (86.7)37 (13.3)1.05 (0.95–1.15)0.358 Socio-economic position (SEP) Low287 (55.2)252 (87.8)35 (12.2)11High220 (42.3)177 (80.5)43 (19.5)0.92 (0.86–0.98)0.0090.90 (0.84 – 0.96)0.001Missing13 (2.5)12 (92.3)1 (7.7) Type of cART Tenofovir (TDF)+emtricitabine (FTC)+nevirapine (NVP)61 (11.7)48 (78.7)13 (21.3)11TDF+FTC+efavirenz (EFV)182 (35.0)154 (84.6)28 (15.4)1.08 (0.95–1.22)0.261.09 (0.96–1.25)0.187Stavudine (d4T)+lamivudine (3TC)+NVP197 (37.9)168 (85.3)29 (14.7)1.08 (0.97–1.21)0.1581.05 (0.94–1.18)0.379Zidovudine (ZDV)+3TC+EFV78 (15.0)70 (89.7)8 (10.3)1.14 (1.01–1.28)0.0271.11 (0.99–1.25)0.071Missing2 (0.4)2 (100.0)0 (0.0) History of tuberculosis No108 (20.8)92 (85.2)16 (14.8)11Yes412 (79.2)350 (85.0)62 (15.0)1.00 (0.89–1.11)0.9611.01 (0.91–1.13)0.818 Current depression No416 (80.0)355 (85.3)61 (14.7)11Yes77 (14.8)63 (81.8)14 (18.2)0.96 (0.84–1.09)0.5230.96 (0.84–1.09)0.493Missing27 (5.2)24 (88.9)3 (11.1)Of the 520 patients, 442 (85.0%) had HIV suppression while 78 (15.0%) did not. At univariable analysis, having high SEP was negatively associated with HIV suppression while receiving ZDV+3TC+EFV was positively associated with HIV suppression. At multivariable analysis, patients with high SEP were less likely to have HIV suppression than those with low SEP.ConclusionsPatients with high SEP were found to be at risk of having unsuppressed HIV. There is need for targeted interventions that can improve HIV outcomes in this group of patients receiving cART in Zambia.