Feasibility Test of Personalized (N-of-1) Trials for Increasing Middle-Aged and Older Adults' Physical Activity

Purpose

To test the feasibility of a remotely-delivered intervention to increase low-intensity physical activity (walking) in middle-aged and older adults.

Design

This study used a Personalized (N-of-1) trial design.

Setting

This study took place at a major healthcare system from November 2021 to February 2022.

Subjects

Sixty adults (45-75 years, 92% female, 80% white) were recruited.

Intervention

A 10-week study comprising a 2-week baseline, followed by four 2-week periods where 4 Behavior Change Techniques (BCTs) - self-monitoring, goal setting, action planning and feedback - were delivered one at a time in random order.

Measures

Activity was measured by a Fitbit, and intervention components delivered by email/text. Average daily steps were compared between baseline and intervention. Participants completed satisfaction items derived from the System Usability Scale and reported attitudes and opinions about personalized trials.

Results

Participants rated personalized trial components as feasible and acceptable. Changes in steps between baseline and intervention were not significant, but a large heterogeneity of treatment effects existed, suggesting some participants significantly increased walking while others significantly decreased.

Conclusions

Our intervention was well-accepted but use of BCTs delivered individually did not result in a significant increase in steps. Feasibility and heterogeneity of treatment effects support adopting a personalized trial approach to optimize intervention results.

Acute Experiences of Negative Interpersonal Interactions: Examining the Dynamics of Negative Mood and Ambulatory Blood Pressure Responses Among Black and Hispanic Urban Adults

BACKGROUND

Negative interpersonal interactions are associated with acute increases in ambulatory blood pressure (ABP). Yet, the mechanisms underlying this relationship are unclear.

PURPOSE

This study tested whether negative interpersonal interactions predict higher ABP both in the moment and during subsequent observations, and whether increases in negative mood mediate these relations. These associations were tested among Black and Hispanic urban adults who may be at higher risk for negative interpersonal interactions as a function of discrimination. Race/ethnicity and lifetime discrimination were tested as moderators.

METHODS

Using a 24-hr ecological momentary assessment (EMA) design, 565 Black and Hispanic participants (aged 23-65, M = 39.06, SD = 9.35; 51.68% men) had their ABP assessed every 20 min during daytime accompanied by an assessment of negative interpersonal interactions and mood. This produced 12,171 paired assessments of ABP and self-reports of participants' interpersonal interactions, including how much the interaction made them feel left out, harassed, and treated unfairly, as well as how angry, nervous, and sad they felt.

RESULTS

Multilevel models revealed that more intense negative interpersonal interactions predicted higher momentary ABP. Mediation analyses revealed that increased negative mood explained the relationship between negative interpersonal interactions and ABP in concurrent and lagged analyses. Discrimination was associated with more negative interpersonal interactions, but neither race/ethnicity nor lifetime discrimination moderated findings.

CONCLUSIONS

Results provide a clearer understanding of the psychobiological mechanisms through which interpersonal interactions influence cardiovascular health and may contribute to health disparities. Implications include the potential for just-in-time interventions to provide mood restoring resources after negative interactions.

Testing Behavior Change Techniques to Increase Physical Activity in Middle-Aged and Older Adults: Protocol for a Randomized Personalized Trial Series

BACKGROUND

Being physically active is critical to successful aging, but most middle-aged and older adults do not move enough. Research has shown that even small increases in activity can have a significant impact on risk reduction and improve quality of life. Some behavior change techniques (BCTs) can increase activity, but prior studies on their effectiveness have primarily tested them in between-subjects trials and in aggregate. These design approaches, while robust, fail to identify those BCTs most influential for a given individual. In contrast, a personalized, or N-of-1, trial design can assess a person's response to each specific intervention.

OBJECTIVE

This study is designed to test the feasibility, acceptability, and preliminary effectiveness of a remotely delivered personalized behavioral intervention to increase low-intensity physical activity (ie, walking) in adults aged 45 to 75 years.

METHODS

The intervention will be administered over 10 weeks, starting with a 2-week baseline period followed by 4 BCTs (goal-setting, self-monitoring, feedback, and action planning) delivered one at a time, each for 2 weeks. In total, 60 participants will be randomized post baseline to 1 of 24 intervention sequences. Physical activity will be continuously measured by a wearable activity tracker, and intervention components and outcome measures will be delivered and collected by email, SMS text messages, and surveys. The effect of the overall intervention on step counts relative to baseline will be examined using generalized linear mixed models with an autoregressive model that accounts for possible autocorrelation and linear trends for daily steps across time. Participant satisfaction with the study components and attitudes and opinions toward personalized trials will be measured at the intervention's conclusion.

RESULTS

Pooled change in daily step count will be reported between baseline and individual BCTs and baseline versus overall intervention. Self-efficacy scores will be compared between baseline and individual BCTs and between baseline and the overall intervention. Mean and SD will be reported for survey measures (participant satisfaction with study components and attitudes and opinions toward personalized trials).

CONCLUSIONS

Assessing the feasibility and acceptability of delivering a personalized, remote physical activity intervention for middle-aged and older adults will inform what steps will be needed to scale up to a fully powered and within-subjects experimental design remotely. Examining the effect of each BCT in isolation will allow for their unique impact to be assessed and support design of future behavioral interventions. In using a personalized trial design, the heterogeneity of individual responses for each BCT can be quantified and inform later National Institutes of Health stages of intervention development trials.

TRIAL REGISTRATION

clinicaltrials.gov NCT04967313; https://clinicaltrials.gov/ct2/show/NCT04967313.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/43418.

Protocol of a feasibility study of a virtual personalized (N-of-1) trial for increasing low-intensity physical activity in older adults via habit formation

Background

Personalized interventions that can be delivered remotely are needed to increase physical activity (PA) in older adults to reduce risk of CV disease and mortality. Prior research indicates that Behavioral Change Techniques (BCTs) (e.g., goal setting, self-monitoring, behavioral repetition) can instill a habit for increasing daily walking. However, past interventions relied on between-subject randomized clinical trials, which can only only be informative about response of the hypothetical average person. Personalized trial designs can identify the benefits of an intervention for a specific individual although extended periods are required for collecting frequent measurements within-subject. Advances in remote, virtual technologies (e.g., text messaging, activity trackers), integrated with automatic platforms, can meet these requirements because they capacitate delivery of BCT interventions, and collection of data during daily life without personal contact. This Stage I-b trial is designed test whether a virtual, personalized intervention is feasible and acceptable to older adults, can elicit participant adherence and exhibit preliminary evidence for efficacy.

Methods

A series of up to 60 single-arm, personalized trials, involving no personal contact, will recruit adults, 45-75 years of age, to wear an activity tracker during a 2-week baseline and a 10-week intervention. Five BCT prompts to execute a walking plan will be delivered on a daily basis during the intervention phase. Participants will rate satisfaction with personalized trial components and whether automaticity of the walking plan can be achieved. Step-counts, adherence to the walking plan and self-monitoring of step-count will also be recorded.