HIV-positive men who have sex with men (MSM) in Switzerland have been engaging in what’s known as chemsex at an increasing rate over the past decade, according to a new study.

Chemsex typically refers to sex between men that involves multiple partners and the use of drugs such as crystal methamphetamine, mephedrone, GHB/GBL, MDMA, amphetamine, cocaine and sometimes ketamine. Such men often meet partners for chemsex through hookup apps such as Grindr.

The study was led by Benjamin Hampel, MD, and Katharina Kusejko, MD, of the Division of Infectious Diseases and Hospital Epidemiology at the University Hospital Zürich. Publishing their findings in HIV Medicine, the study authors analyzed 166,167 follow-up responses from 12,527 participants of the Swiss HIV Cohort Study (SHCS) from 2007 to 2017.

Specifically, the researchers looked for reports from the study participants, who are all living with HIV, about recreational drug use.

An estimated 84% of all HIV-positive MSM living in Switzerland participated in the cohort.

There were data from 5,657 participants in the study between 2007 and 2017. A total of 2,510 (44.4%) of them reported drug use at least once during this period. After excluding marijuana, amyl nitrate (poppers), benzodiazepines (tranquilizers such as Xanax) and other prescription drugs, this left 1,468 (25.9%) men reporting drug use.

There was a statistically significant increase, meaning it is not likely to have been driven by chance, during the study period in the men’s rate of use of GHB (from 1.0% to 3.4%), meth (from 0.2% to 2.4%), mephedrone (from 0.0% to 0.2%), cocaine (from 6.2% to 9.9%), XTC/MDMA (from 3.2% to 5.3%) and amphetamine (from 0.4% from 1.0%). There was a non-statistically significant rise, meaning it could have been driven by chance, in the men’s use of

ketamine (from 0.1% to 0.7%).

Compared with non–drug users, those who reported using any of the five main chemsex drugs—GHB/GBL, meth, cocaine, XTC/MDMA and amphetamine—had higher rates of hepatitis C virus coinfection, syphilis, depression and condomless intercourse with casual partners.

Those who used GHB/GBL, cocaine and amphetamine were less likely to adhere to their antiretroviral regimens compared with non–drug users.

“The significant increase in the use of chemsex drugs among MSM in the SHCS and the strong association with coinfections and depression highlights the need for harm reduction programs tailored to MSM,” the study authors concluded. “According to our results, improving knowledge about recreational drugs is important for all health care professionals working with people living with HIV.”

To read the study abstract, click here.