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 208
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.