Optimization of a Behavioral Intervention to Increase Physical Activity in Older Adults Living With HIV

Increasing numbers of persons living with HIV (PLWH) are living to older ages. Older PLWH are at increased risk for a wide spectrum of co-morbid conditions such as cardiovascular disease, frailty phenotype, and mental health disorders. Practical primary care-based interventions are needed for older PLWH that target lifestyle factors to reduce complications of aging and improve healthspan. Most PLWH engage in less physical activity (PA) than is recommended by public health guidelines. Thus, increasing PA can lead to numerous mental and physical health benefits among PLWH. Current studies in PLWH typically focus on the impact of supervised exercise. However, there are many barriers to this type of PA. Lifestyle physical activity (LPA) programs that focus on integrating PA, especially walking, into everyday life, may be more successful in producing a sustained increase in PA. The long-term goal of this research is to develop an effective and efficient primary care intervention that increases LPA among older PLWH. We leverage the Multiphase Optimization STrategy (MOST) as a framework for developing, optimizing, and evaluating a multicomponent behavioral intervention. MOST is comprised of three phases. First, in the preparation phase, an empirical and theory-driven conceptual model is developed that identifies differentiable intervention components and specifies optimization criteria (i.e., goal of intervention development). We have completed this phase. Second, in the optimization phase, the impact of each intervention component on the desired outcome is empirically examined. The goal is to determine which components to include in a final intervention package that is optimized for efficacy and efficiency. The proposed study reflects the second phase, or an optimization trial. Finally, in the evaluation phase, the optimized intervention package is evaluated for efficacy in a traditional RCT; this will be the next step in this line of research following the currently proposed project. In this project, we will test the impact of three separable intervention components on steps per day after 4 months of intervention. We will recruit 196 PLWH of age ≥50 year classified as low-active. All participants receive component '0': brief advice to exercise and a Fitbit activity tracker. We then test 3 additional components in a factorial design: 1) PA Coaching-focused on goal-setting and self-monitoring; 2) Cognitive-Behavioral intervention for PA (CB-PA)-focused on identifying values and addressing internal barriers to PA such as pain, depression, or fatigue; 3) Social Support for PA (SS-PA)-a component which leverages the social functionality of the Fitbit app, promoting social support and friendly competition. The primary outcome will be steps per day during Month 4. The observed main and interaction effects for the 3 candidate components will guide selection of components to be included in an optimized intervention that will be tested in a future RCT. We will also examine potential mediators for each intervention component, as well as secondary outcomes including perceived physical health, mental health, cardiovascular disease risk, and the frailty phenotype.

Inclusion criteria

• HIV positive: defined by HIV antibody, detectable HIV RNA in plasma, or a note from the participant's HIV care provider.
• Must be on continuous antiretroviral therapy (ART) for > 3 months, as assessed via self-report.
• Low PA: defined as self-report of < 90 minutes of moderate-vigorous PA (MVPA) per week in the previous 3 months AND less than 14 hours per week of sustained walking in the previous 4 weeks.
• Medically cleared for moderate PA. If participants report a) a history of cardiovascular disease including known coronary artery disease, peripheral vascular disease, heart failure, or stroke; or b) chest pain, shortness of breath, or dizziness or syncope either at rest or during activity in the past 3 months, then they must have medical clearance by a physician or primary care provider.
• Age 50 years or older.
• Proficiency in English: sufficient to engage in informed consent, understand assessments and materials provided, and engage and use Fitbit application (all materials provided in English).
• Capacity to consent, documented by acceptable answers in a consent "teach-back" process.
• Score of greater than 16 on the MOCA
• Able to ambulate without assistive devices
• Ability to use the FitBit application, as demonstrated to study staff.

Exclusion criteria

• Exclusion Criteria

• Medical conditions or physical or neurocognitive limitations that interfere with PA or study participation.
• Hazardous substance use, assessed via a score ≥15 on the Alcohol Use Disorders Identification Test (AUDIT) or ≥6 on the Drug Abuse Screening Test (DAST).