Injecting drug use
Are females who inject drugs at higher risk for HIV infection than males who inject drugs: An international systematic review of high seroprevalence areas
Des Jarlais DC, Feelemyer JP, Modi SN, Arasteh K, Hagan H. Drug Alcohol Depend. 2012 Jan 16. [Epub ahead of print]
There are multiple reasons why females who inject drugs may be more likely to become infected with HIV than males who inject drugs. Where this is the case, special HIV prevention programs for females would be needed. Des Jarlais and colleagues undertook an international systematic review and meta-analysis of studies across 14 countries. Countries with high seroprevalence (>20%) HIV epidemics among persons who inject drugs (PWID) were identified from the Reference Group to the United Nations on HIV and Injecting Drug Use. Systematic literature reviews collected data on HIV prevalence by sex for these countries. Non-parametric and parametric tests along with meta-analytic techniques examined heterogeneity and differences in odds ratios across studies. Data were abstracted from 117 studies in 14 countries; total sample size N=128,745. The mean weighted odds ratios for HIV prevalence among females to males was 1.18 [95% CI 1.10-1.26], with high heterogeneity among studies (I(2)=70.7%). There was a Gaussian distribution of the log odds ratios across studies in the sample. There was a significantly higher HIV prevalence among females compared to males who inject drugs in high seroprevalence settings, but the effect size is extremely modest. The high level of heterogeneity and the Gaussian distribution suggest multiple causes of differences in HIV prevalence between females and males, with a specific difference determined by local factors. Greater understanding of factors that may protect females from HIV infection may provide insights into more effective HIV prevention for both females and males who inject drugs.
Editor’s note: In this first systematic review to assess sex differences in HIV prevalence among people who inject drugs, the 14 countries chosen for analysis had at one time a greater than 20% HIV prevalence among people who inject drugs and had published data from 1985, when HIV antibody tests became available, up until June 2011. They were: Argentina, Brazil, China, Estonia, France, Italy, the Netherlands, Puerto Rico, Russia, Scotland, Spain, Ukraine, Viet Nam, and USA (New York City only). Pooled data from 117 studies with 132 female:male HIV prevalence odds ratio comparisons revealed that there was only a slightly higher HIV prevalence found in women compared to men, with no difference by low- and middle-income countries versus high-income countries. This is encouraging since it suggests that interventions to reduce injecting-related HIV transmission such as large-scale needle/syringe access programmes are effective for both genders. Since many women injectors either rely on men to inject them or use their partner’s injecting equipment, protecting men from acquiring HIV provides indirect benefits to women. The authors of the 10 studies with the greatest sex differences attributed the higher female rates they found to factors related to sexual transmission while the authors of the 10 studies with the lowest female:male ratios proposed no explanations other than that they had only a small number of women in the samples. Knowing more about why and how some women injectors appear to be protected can help improve the effectiveness of HIV prevention programmes among all people who inject drugs.