Characteristics of included reviews
| Review, yr | Search performed | Population | Included study settings (by income level)* | Study designs included | Analysis of interest | AMSTA R (score out of 11) | Other characteristics |
|---|---|---|---|---|---|---|---|
| Supervie et al., 201421 |
| Serodiscordant heterosexual couples | Primarily lower-middle– and upper-middle–income countries (2 studies with sites in high-income countries) | RCT, retrospective and prospective cohorts | Bayesian modelling to develop per-act risk of HIV transmission when the partner with HIV is on ART for more than 6 mo. | 7 | Studies had to include information on viral load of partner on ART, condom use and sexual activity. |
| Patel et al., 20148 |
| Serodiscordant heterosexual and MSM couples | Low-, lower-middle–, upper-middle– and high-income countries | Systematic review and meta-analysis, prospective cohort, cross-sectional | Transmission risk with ART and/or condoms calculated by multiplying unprotected risk estimates by relative risk reductions of 96% (ART), 80% (condoms) or 99.2% (ART and condoms). | 2 | Estimates for transmission risk with ART and condoms derived from Cohen et al. (assumed 96% risk reduction),40 and Weller and Davis (80% risk reduction),7 respectively. |
| Loutfy et al., 20136 |
| Serodiscordant heterosexual couples | Primarily lower-middle– and upper-middle–income countries (2 studies with sites in high-income countries) | For undetectable VL: retrospective and prospective cohorts, cross-sectional For unconfirmed VL: RCT, 2 prospective cohorts | Fixed-effects Poisson regression model to develop summary statistics for the effect of ART use stratified by confirmed undetectable VL and unconfirmed undetectable VL. | 7 | Identified studies did not provide enough data on same-sex couples to generate risk estimates. Insufficient evidence to develop estimates for exclusively condomless sex (condom use high in most studies) or for various sexual acts. |
| Anglemyer et al., 201338 |
| Serodiscordant couples (most were heterosexual) | Primarily lower-middle– and upper-middle–income countries (3 studies with sites in high-income countries) | RCT, prospective and retrospective cohorts | Summary rate ratios across studies used to calculate absolute incidence rates for ART use based on baseline incidence in control group. | 9 | Risks stratified based on linked and unlinked HIV transmissions, and by CD4 cell count subgroups. Unable to estimate levels of ART use (i.e., adherence) or prevalence of condom use. |
| Baggaley et al., 201336 |
| Serodiscordant heterosexual couples | Primarily low- and lower-middle–income countries (1 study with site in high-income country) | For studies including a no ART arm: RCT, prospective cohort For studies with no comparison group with respect to ART use: prospective cohort | Random-effects Poisson regression model for summary statistics of risk with ART use, stratified by setting (high v. low-middle income). No summary statistics calculated for studies with no comparison group. | 3 | Separate analyses for studies with a comparator (no ART) group and for those with no comparison group. Studies with no comparison group had a variety of reported ART use levels. |
| Baggaley et al., 201037 |
| Serodiscordant heterosexual couples and MSM, and individuals at risk of HIV | Low-, lower-middle–, upper-middle –and high-income countries Low-income countries were used to derive the ART risk estimate. | Prospective and retrospective cohorts | Two models used to estimate risk with successful ART (resulting in viral suppression) | 3 | Estimates for ART based on 2 models derived from single studies of heterosexual transmission in Uganda and Zambia.41,42 |
| Attia et al., 200939 |
| Serodiscordant heterosexual couples | Primarily low- and upper-middle–income (3 studies with sites in high-income countries) | Prospective cohort | Random-effects Poisson regression for effect of ART and viral load | 4 | Stratified by ART, no ART and ART at various VLs. Authors were unable to control for condom use. |
| Boily et al., 200935 |
| Serodiscordant heterosexual couples including sex workers and their clients and individuals at risk of HIV | Low-, lower-middle–, upper-middle–and high-income countries | Prospective and retrospective cohorts, cross-sectional | Univariate meta-regression for condom effectiveness | 5 | Control versus no control for condom use. Condom use was considered controlled for if any attempt was made to account for frequent condom use or if condom use was very low. |
| Powers et al., 200832 |
| Serodiscordant heterosexual couples and individuals at risk of HIV | Low-, lower-middle–, upper-middle–and high-income countries | Prospective cohort, cross-sectional | Univariate meta-regression for condom effectiveness | 3 | Compared “some” condom use with “rare” condom use or adjusted for condom use |
| Weller and Davis, 20027 |
| Serodiscordant heterosexual couples | Low-, lower-middle– and high-income countries | Prospective and retrospective cohorts, case study | Summary statistic for condom effectiveness | 4 | Compared “never” condom use to “always” condom use as reported in the included studies |
| Liu et al., 201433 |
| Serodiscordant heterosexual couples | Upper-middle–income country | Prospective cohort | Random-effects Poisson regression models to produce pooled estimates of HIV incidence on ART and with condom use. | 3 | On ART compared with no ART and “consistent” condom use compared with inconsistent condom use (based on self-report) |
| Cambiano et al., 201334 |
| Serodiscordant heterosexual couples | Low-, lower-middle–, upper-middle– and high-income countries | Systematic review and meta-analysis, RCT, prospective and retrospective cohorts, cross-sectional, mathematical model | Narrative synthesis of various HIV transmission risk and incidence estimates for ART use for various acts | 2 | No direct evidence for HIV transmission risk for MSM was available. Cites other reviews identified in this overview.6,36,38,39 |
Note: AMSTAR = A Measurement Tool to Assess Systematic Reviews, ART = antiretroviral therapy, CDC = US Centers for Disease Control and Prevention, CINAHL = Cumulative Index to Nursing and Allied Health Literature, CROI = Conference on Retroviruses and Opportunistic Infections, IAC = International AIDS Conference, IAS = International AIDS Society, ISSTR = International Society of Sexually Transmitted Research, LILACS = Latin American and Caribbean Health Sciences Literature database, MSM = men who have sex with men, NLM = National Library of Medicine, PrEP = Pre-Exposure Prophylaxis, RCT = randomized controlled trial, VL = viral load.
↵* Study setting groupings by income level based on the World Bank’s country and lending group classification for the 2017 fiscal year.43