Prevalence and behavioural risks for HIV and HCV infections in a population of drug users of Dakar, Senegal: the ANRS 12243 UDSEN study

Abstract

ObjectivesData on the extent of drug use and associated HIV, hepatitis C and hepatitis B infection in West Africa are lacking. The objectives of ANRS12244 UDSEN study were to estimate the size of the heroin and/or cocaine drug user (DU) population living in the Dakar area (Senegal), and assess the prevalence and risk factors of HIV, hepatitis C virus (HCV) and hepatitis B virus (HBV), including behavioural determinants in this population, in order to set up an integrated prevention and treatment programme for DUs.Design and methodsA capture-recapture method was applied for population size estimation, whereas the respondent-driven sampling (RDS) method was used to recruit a sample of DUs living in the Dakar area and determine HIV, HBV and HCV prevalence. Behavioural data were gathered during face-to-face interviews, and blood samples were collected on dried blood spots for analysis in a central laboratory. Data analysis was performed using the RDS analysis tool, and risk factors were determined by logistic regression. Access to laboratory results was organized for the participants.ResultsThe size of the DU population in the Dakar area was estimated to reach 1324 (95% confidence interval (95% CI: 1281–1367)). Based on the 506 DUs included in the study, the HIV, HCV and HBV prevalence were 5.2% (95% CI: 3.8–6.3), 23.3% (95% CI: 21.2–25.2) and 7.9% (95% CI: 5.2–11.1), respectively. In people who inject drugs (PWID), prevalence levels increased to 9.4% for HIV and 38.9% for HCV (p=0.001 when compared to those who never injected). Women were more at risk of being HIV infected (prevalence: 13.04% versus 2.97% in males, p=0.001). Being PWID was a risk factor for HCV and HIV infection (odds ratio, OR: 2.7, 95% CI: 1.7–4.3, and OR: 4.3, 95% CI: 1.7–10.7, respectively), whereas older age and female sex were additional risk factors for HIV infection (10% increase per year of age, p=0.03 and OR: 4.9, 95% CI: 1.6–156, respectively). No specific determinant was associated with the risk of HBV infection.ConclusionsHigh HIV and HCV prevalence were estimated in this population of DUs (including non-injectors) living in the Dakar area, Senegal, whereas HBV prevalence was close to that of the global Senegalese population, reflecting a risk of infection independent of drug use. Women seem to be highly vulnerable and deserve targeted interventions for decreasing exposure to HIV, while behavioural risk factors for HIV and HCV include the use of unsafe injections, reflecting the urgent need for developing harm reduction interventions and access to opioid substitution therapy services.

Response to comments by Hønge et al. on our paper titled “Prevalence of hepatitis B markers in Senegalese HIV‐1 infected patients”

“…The HBsAg prevalence was evaluated by Ndiaye et al [2015] in a military population with 70% of men, and the prevalence was between 9.9% and 12.7% . A recent study in Senegalese drug user (ANRS UDSEN) showed a prevalence of HBsAg (7.9%), similar to ours, on a sample size of (n ¼ 506) [Leprêtre et al, 2015]. Statistical analysis comparing these three recent studies (Table I) did not show a significant difference (P ¼ 0.139).…”

“… P 2 is the prevalence obtained by Lô et al [] which is statistically different to that published by Leprêtre et al ().…”

“…This would raise new interesting research ideas and outputs that could improve the monitoring and/or the control of HBV, particularly in Senegalese HIVinfected patients and in the general population. Prevalence (%) P-value Lô et al [2015] 8.8 Ndiaye et al [2015] 10.8 P1 ¼ 0.264 Lô et al [2015] 8.8 P ¼ 0.139 Leprêtre et al [2015] 7.9 P2 ¼ 0.698 P1 is the prevalence obtained by Lô et al [2015] which is statistically different to that published by Ndiaye et al [2015]. P2 is the prevalence obtained by Lô et al [2015] which is statistically different to that published by Leprêtre et al (2015).…”

Trends in life expectancy of HIV-positive adults on antiretroviral therapy across the globe

“…Differences in life expectancy across studies from high-income countries might be partly explained by the proportion of PWID in each population: the two studies with the lowest life expectancy estimates also had the highest proportion of PWID [10,11], whereas life expectancy was highest among studies with fewer PWIDs [8,12–14,18]. Although injection drug use has increased in several large African cities [27], data on drug consumption is only rarely reported and generally not systematically assessed. Indeed, no information on IDU was available from the three African studies included in this review.…”

Usefulness of Dried Blood Spots (DBS) to perform hepatitis C virus genotyping in drug users in Senegal

“…Prevalence of HCV is very high among DUs group, reaching 22 to 94% in some studies [Fadlalla et al, ]. A recent study in Senegal, showed a prevalence of 23.3% for anti‐HCV antibodies [Leprêtre et al, ], which is very high comparing to HIV‐positive patients (1.6%) [Diop‐Ndiaye et al, ] or blood donors (1.4%) [Dieye et al, ]. However, few data on HCV is available in the country and especially on circulating genotypes and there is a real need to make an update.…”