Development of an Ecological Momentary Assessment Study to Identify Real-Time Predictors of Physical Activity among Older People with HIV: a Study Protocol (Preprint)

BACKGROUND People with HIV (PWH) are aging rapidly and face accelerated aging-related comorbidities, including cardiovascular diseases and cognitive impairment, due to prolonged HIV-associated inflammation. Physical activity (PA) is a well-established intervention to mitigate these risks, yet the majority of older PWH remain sedentary. Despite considerable efforts to understand PA determinants and design interventions for PWH, outcomes have been suboptimal. OBJECTIVE The overarching goal of this project is to use an ecological momentary assessment (EMA) approach to capture ecologically valid relations between older PWH’s personal experiences and PA as they engage in their normal daily activities. METHODS This study will adopt a two-phase mixed method research design. The first phase focuses on developing the EMA questionnaire through in-depth interviews with older PWH to explore the relevance of candidate real-time predictors of PA, identified using the Capacity, Opportunity, Motivation - Behavioral (COM-B) framework and literature review, to their daily experiences. These interviews will validate and refine the constructs for the EMA survey. In phase two, a two-week EMA study will collect data from 70 sedentary older PWH through smartphone surveys (3 times/day) and Fitbit-measured step counts and moderate-to-vigorous physical activity (MVPA) minutes. Multilevel modeling will be used to examine how these factors predict daily PA levels. RESULTS N/A CONCLUSIONS By advancing the understanding of real-time determinants of PA, this study addresses a critical gap in the literature and offers a foundation for designing Just-in-Time Adaptive Interventions that deliver tailored, context-specific support to enhance PA engagement tailored interventions that support healthy aging among older PWH.