JomCare Study - A Harm Reduction Study

Chemsex, the use of psychoactive drugs before or during sexual activity, is a growing public health concern due to its association with increased HIV transmission and other harms, particularly among men who have sex with men (MSM). Current estimates suggest that 9-26% of Malaysian MSM participate in chemsex, contributing to recent increases in HIV prevalence. In the absence of evidence-based interventions for chemsex, harm reduction strategies remain the most impactful approach to mitigating chemsex-associated harms. However, getting harm reduction interventions to MSM who engage in chemsex is a major challenge due to the spontaneous and dynamic nature of chemsex risk. Just-in-time adaptive interventions (JITAIs) delivered via smartphones represent a powerful strategy to deliver support by deploying tailored intervention when needed. Specifically, apps that incorporate JITAI can be more effective than traditional app-based interventions by addressing the dynamic nature of chemsex risk and capitalizing on users' changing states of vulnerability (heightened chemsex risk behaviors) and receptivity (willingness to engage in intervention), while also minimizing user burden, disruption, and habituation. Although JITAIs are increasingly being used in domains such as addiction, mental health disorders, physical inactivity, and obesity, research on JITAIs to address chemsex harm reduction is non-existent. In response, a smartphone app-based chemsex harm reduction JITAI called JomCare is developed that uses a machine learning algorithm to determine risk and deliver tailored support as needed. JomCare includes several 'pull' and 'push' intervention components based on the information-motivation-behavioral skills (IMB) model, and has demonstrated high feasibility and utility in our recent pilot work. However, little is known to guide which intervention components should be delivered in specific contexts to achieve maximum benefit, thus indicating the need to optimize JomCare. Framed by the multiphase optimization strategy (MOST) and building on our formative work, this study will optimize JomCare using a micro-randomized trial (MRT) to evaluate: i) which theory-driven intervention components are efficacious in reducing chemsex risk behaviors; and ii) which contexts influence the efficacy of JomCare. Specifically, this study will conduct a 90-day MRT of the JomCare JITAI among 482 chemsex-involved Malaysian MSM. Participants will be randomized twice daily via the app to receive: i) no prompt; ii) a generic engagement prompt; or iii) one of three IMB model-based engagement prompts. The specific aims of this application include: i) Evaluate the effects of any intervention (i.e., theory-driven or generic engagement prompts) versus no intervention on chemsex risk behaviors (proximal outcomes) at subsequent EMAs following randomization; ii) Compare the effects of theory-driven and generic engagement prompts on proximal outcomes; and iii) Examine contextual moderators of intervention on proximal outcomes.

Information-based engagement prompts are expected to improve participants' knowledge of harm reduction needs by providing information relevant to HIV (e.g., HIV/STI risk reduction), chemsex (e.g., safer drug use, CAD overdose prevention, drug interactions), and other topics (e.g., mental health).

Behavioral: JomCare is a smartphone-based just-in-time adaptive intervention (JITAI) for chemsex-related harm reduction.

Motivation-based engagement prompts are expected to increase the salience of participants' beliefs about the importance of their harm reduction needs.

Behavioral: JomCare is a smartphone-based just-in-time adaptive intervention (JITAI) for chemsex-related harm reduction.

Behavioral skills-based engagement prompts are expected to improve self-efficacy and the ability to engage in intervention.

Behavioral: JomCare is a smartphone-based just-in-time adaptive intervention (JITAI) for chemsex-related harm reduction.

Generic engagement prompts are included as active comparators to the theory-driven components, as they control for the potential influence of receiving any engagement prompts. Given the aim to optimize JITAI, including generic prompts provides the mechanism for distinguishing the effects of receiving any prompt from the theory-driven prompts.

Behavioral: JomCare is a smartphone-based just-in-time adaptive intervention (JITAI) for chemsex-related harm reduction.

No engagement prompt is included as an inactive comparator. Participants will not receive any prompt when randomized to this group. Inclusion of the "no engagement prompt" will control for the potential impact of being notified of heightened risk, which could activate any pre-existing strategies to reduce or prevent risk.

JomCare is a smartphone-based just-in-time adaptive intervention (JITAI) that uses an EMA-based machine learning (ML) algorithm to anticipate chemsex risk and deliver appropriate chemsex-related harm reduction and HIV prevention services when the risk is detected.

Time frame: Up to 6 months

Use of chemsex-associated drugs, engagement in condomless anal sex, CAD overdose since the last EMA

Optimizing a Just-in-Time Adaptive Intervention to Increase Uptake of Chemsex Harm Reduction Services in MSM: A Micro-randomized Trial