Introduction
Assisted partner services (aPS), a strategy to test and link to care the sexual partners of
HIV infected persons, is effective in finding new HIV cases. This study assessed
whether the effectiveness of aPS differs by region, rural location and gender in a
cluster-randomized controlled trial in Kenya.
Methods
Eighteen HIV testing sites were randomized to either provide immediate or delayed
aPS. We investigated whether there were interactions between receiving immediate
aPS and region (Nairobi/Central vs Nyanza). Generalized estimating equations with a
Poisson link, robust standard errors and exchangeable correlation structure were used
to assess whether the effectiveness of receiving immediate aPS in getting a sexual
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partner tested, newly diagnosed with HIV, and linked to care was modified by region
(Nairobi/Central vs. Nyanza), testing location (urban vs. rural/peri-urban), and gender.
Results
We enrolled 1119 index clients and 1286 partners between August 2013 and June
2015. The effectiveness of aPS in getting a sexual partner tested for HIV was modified
by region (p=0.001), location (p=0.018), and gender (p=0.061). Comparing the
immediate and the delayed arm, partner testing increased 7 fold in Nyanza compared
to a 3 fold increase in Nairobi (Incidence Rate Ratio (IRR) 7.2; 95% Confidence Interval
(CI) 5.4, 9.6 vs IRR 3.4 95%CI 2.3, 4.8), a 7 fold increase in rural/peri-urban sites
compared to a 4 fold increase in urban sites (IRR 6.6; 95%CI 4.5, 9.6 vs. IRR 3.54
95%CI 2.5, 5.0), and a 6 fold increase in female index clients compared to a 4 fold
increase in male index clients (IRR 5.8 95%CI 4.2, 7.9 vs IRR 3.7; 95% CI 2.4, 5.8)). In
addition, there was a 9 fold increase in newly diagnosing a partner with HIV among
female index clients compared to a 3 fold increase among male index clients (IRR 9.1;
95% CI 4.0, 20.9 vs IRR 3.2 95% CI 1.7, 6.0).
Conclusions
While immediate aPS was effective among the overall study population in Kenya, the
size of the effect differed by region, location, and gender. These differences can help to
guide the target populations and geographies for aPS as it is rolled out in Kenya.