Treatment of helminth co-infection in HIV-1 infected individuals in resource-limited settings

Abstract

Background: The HIV-1 pandemic has disproportionately affected individuals in resource-constrained settings. These areas often also have high prevalence of other infectious diseases, such as helminth infections. It is important to determine if helminth infection affects the progression of HIV-1 in these co-infected individuals. There are biologically plausible reasons for possible effects of helminth infection in HIV-1 infected individuals and findings from some observational studies suggest that helminth infection may adversely affect HIV-1 progression. We sought to evaluate the available evidence from published and unpublished studies to determine if treatment of helminth infection in HIV-1 co-infected individuals impacts HIV-1 progression.

Objectives: Our objective was to determine if treating helminth infection in individuals with HIV-1 can reduce the progression of HIV-1 as determined by changes in CD4 count, viral load, or clinical disease progression (including mortality).

Search strategy: We searched online for published and unpublished studies in The Cochrane Library (Issue 3, 2006), MEDLINE (November 2006), EMBASE (November 2006), CENTRAL (July 2006), AIDSEARCH (August 2006). We also searched databases listing conference abstracts, scanned reference lists of articles, and contacted authors of included studies.

Selection criteria: We searched for randomized and quasi-randomized controlled trials that compared HIV-1 progression as measured by changes in CD4 count, viral load, or clinical disease progression in HIV-1 infected individuals receiving anti-helminth therapy. Observational studies with relevant data were also included.

Data collection and analysis: Data regarding changes in CD4 count, HIV-1 RNA levels, clinical staging and/or mortality after treatment of helminth co-infection were extracted from the reports of the studies.

Main results: Of 6,384 abstracts identified, 15 met criteria for potential inclusion, of which five were eligible for inclusion. In the single randomized controlled trial (RCT) identified, HIV-1 and schistosomiasis co-infected individuals receiving treatment for schistosomiasis had a significantly lower change in plasma HIV-1 RNA over three months (-0.001 log10 copies/mL) compared to those receiving no treatment (+0.21 log10 copies/mL), (p=0.03). Four observational studies met inclusion criteria and all of these suggested a possible beneficial effect of helminth eradication on plasma HIV-1 RNA levels when compared to plasma HIV-1 RNA changes prior to helminth treatment or to helminth-uninfected or persistently helminth-infected individuals. Follow-up duration in these studies ranged from three to six months. The reported magnitude of effect on HIV-1 RNA was variable, ranging from 0.07-1.05 log10 copies/mL. None of the included studies showed a significant benefit of helminth treatment on CD4 decline, clinical staging, or mortality.

Authors' conclusions: There are insufficient data available to determine the potential benefit of helminth eradication in HIV-1 and helminth co-infected adults. Data from a single RCT and multiple observational studies suggest possible benefit in reducing plasma viral load. The impact of de-worming on markers of HIV-1 progression should be addressed in larger randomized studies evaluating species-specific effects and with a sufficient duration of follow-up to document potential differences on clinical outcomes and CD4 decline.

Figures

Figure 1

Flow chart of study selection process