Changing Pattern of Chemsex Drug Use Among Newly Diagnosed HIV-Positive Taiwanese from 2015 to 2020 in the Era of Treat-All Policy.

Chemsex drug use (CDU) is a frequent, yet neglected issue in the era of treat-all policy. We evaluated the temporal pattern of CDU, factors associated with CDU, and drug-drug interactions (DDIs) between chemsex drugs and initial antiretroviral therapy (ART) by surveying 621 Taiwanese individuals (mean age: 29.7 years; 99.2% men; 92.9% men who have sex with men) diagnosed with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) from 2015 to 2020 [2015 to 2016 (period 1), 2017 to 2018 (period 2), and 2019 to 2020 (period 3)]. CDU was defined as chemsex in the past 1 year before HIV diagnosis. CDU remained prevalent across three periods (34.3-30.5%). Among CDU, methamphetamine (43.4%) was most frequently used, followed by amphetamine (40.0%) and poppers (various alkyl nitrites) (39.5%). We identified significantly increasing amphetamine use (37.0-61.5%) and decreasing ecstasy (methylenedioxy-methamphetamine) use (32.1-17.9%) in CDU across three periods. Besides, polydrug chemsex also significantly increased in CDU across three periods (23.5-43.6%), with amphetamine plus gamma-hydroxybutyrate being the most commonly used combination. CDU was associated with multiple sexual partners and a history of sexually transmitted diseases (STDs). DDIs between chemsex drugs and initial ART remained stable across three periods (10.6-7.8%), with cobicistat/elvitegravir and methamphetamine most common combination. In summary, the magnitude of CDU remained high across 2015-2020 in Taiwan, causing DDIs with initial ART agents. Strategies to reduce the frequency of high-risk sexual practices, STD transmission, and DDIs for newly diagnosed HIV-positive patients engaging in chemsex should be implemented.