Effects of a nucleic acid testing-based one-stop service model on timely initiation of antiretroviral therapy in China: a regression discontinuity study

Nucleic acid testing-based one-stop service models are designed to streamline the HIV care cascade in China. However, evidence on their real-world efficacy in accelerating antiretroviral therapy (ART) initiation remains limited. This study aimed to evaluate the impact of a one-stop service model on achieving ART initiation within 7 and 30 days in provider-initiated testing and counseling (PITC) settings. Using clinical records from three hospitals in Guangdong, China (December 2020–August 2025), we identified 851 newly diagnosed HIV patients. A regression discontinuity design (RDD) was employed, using site-specific implementation dates as cutoffs to estimate the causal effect of the model. Primary outcomes were ART initiation probabilities within 7 and 30 days post-initial screening. Secondary outcomes included the timeliness of confirmatory testing and linkage to care after diagnosis. Model robustness was assessed using alternative bandwidths and placebo tests. Of 851 participants (578 pre-implementation, 273 post-implementation), 83.0% were male and 53.1% were aged over 50. Implementation of the one-stop service model significantly increased ART initiation within 7 days from 16.0% to 47.2% (RD: 31.2%; 95% CI: 4.0%–58.5%) and within 30 days from 70.6% to 92.9% (RD: 22.3%; 95% CI: 3.0%–41.7%). The model was also associated with a higher proportion of patients completing confirmatory testing within 7 days (RD, 26.3%; 95% CI, 0.0%–52.3%), initiating ART within 7 days after confirmatory diagnosis (RD, 31.0%; 95% CI, 4.3%–57.6%), and initiating ART within 30 days after confirmatory diagnosis (RD, 23.3%; 95% CI, 3.4%–43.2%). Effects were more pronounced among older individuals and those who acquired HIV through heterosexual transmission. The one-stop service model significantly improved timely ART initiation by addressing critical bottlenecks in the HIV care cascade. These real-world findings provide robust evidence for scaling up integrated testing-to-treatment services to achieve HIV control targets.