Feasibility, Acceptability, and Potential Impact of Mindfulness-Based Stress Reduction in Older Adults at Risk for Coronary Artery Disease: A Pilot Randomized Trial

The intervention is the standardized Mindfulness-Based Stress Reduction (MBSR) program developed by Dr. John Kabat-Zinn. Participants attended eight weekly 2.5 hour sessions at a community center adjacent to the Montreal Heart Institute. They also attended an additional five hour “retreat” between weeks 7 and 8 which sought to further integrate the skills acquired until that point. The nine sessions of MBSR were delivered over nine weeks rather than the standard eight in order to avoid holding a session on a religious holiday. Sessions were animated by a psychologist and MBSR teacher with over 25 years of psychotherapy experience. They were audio-recorded and reviewed by the senior investigator of this work, Dr. D'Antono, a psychologist with over 20 years of experience in stress management and mindfulness-based stress interventions, in order to ensure adherence to the standardized program.

2016-02-18

2016-04-14

Feasibility
Acceptability

Feasibility was examined via response rate, recruitment rate, and refusal rates. Response rate refers to the number of participants that responded to our initial recruitment letter divided by the total number of participants approached. Recruitment rate was defined as the number of participants that agreed to participate after contacting the laboratory and learning about the study, divided by the total number that responded. Refusal rate refers to the number of participants who refused to participate divided by the total number that responded.

Acceptability was measured via the program completion rate and program attendance. An adapted version of the Treatment Acceptability and Preferences Questionnaire (Sidani, Epstein, Bootzin, Moritz, & Miranda, 2009) was also administered; it consisted of 11 questions measuring the extent to which participants perceived the intervention as efficacious, appropriate and acceptable by means of Likert scales ranging from 0 (not at all) to 4 (extremely).

Reference: Sidani, S., Epstein, D. R., Bootzin, R. R., Moritz, P., & Miranda, J. (2009). Assessment of preferences for treatment: validation of a measure. Research in nursing & health, 32(4), 419-431.

Metabolic syndrome parameters (blood pressure, cholesterol, triglycerides, glucose, and waist circumference)
Cardiovascular (blood pressure; heart rate) and autonomic activity at rest and in response to stress.

Blood samples were analyzed for cholesterol, triglycerides and glucose at the Montreal Heart Institute. These determinations were made using respective reagent Flex on the multianalyzer Dimension RxL Max (Dade Behring Diagnostics, Marburg, Germany) with heparinized plasma. The samples were analyzed upon reception.
Waist circumference was measured via standard measuring tape.
A Finopres Finometer (Amsterdam, The Netherlands) was placed on the middle finger of the participant’s non-dominant hand to measure blood pressure (BP).

Autonomic activity in response to stress were measured via heart rate variability parameters (HRV). These parameters were obtained from an electrocardiogram (ECG) and were analyzed offline in LabChart (ADInstruments, Dunedin, New Zealand). HRV parameters of interest included high frequency (HF; 0.15–0.40 Hz) and low frequency components (LF; 0.04– 0.15 Hz) as recommended by the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996).

BP, heart rate, HF-HRV, LF-HRV readings were averaged over each baseline, stress, and post-stress period. The two stress periods and recovery periods were then averaged to create a composite stress and recovery scores for each parameter. Stress reactivity (stress minus baseline) and recovery (recovery minus baseline) change scores were computed for each parameter.

Reference: Task Force of the European Society of Cardiology. (1996). Heart rate variability standards of measurement, physiological interpretation, and clinical use. Eur Heart J, 17, 354-381.

This pilot RCT was conducted using a pre-post and 2-month follow-up design.

Recruitment letters were sent to the 81 individuals recruited from a previous study who met inclusion criteria for this study. The second mailing (to the same individuals) was conducted approximately six weeks after the first. Interested individuals were instructed to contact the laboratory and were then screened by phone for exclusion criteria before they were officially invited to participate. Once they were deemed eligible, their availabilities for the MBSR intervention were collected, and a final schedule was chosen in an attempt to accommodate the greatest number of participants. Participants who were available during the pre-determined timeslot for MBSR were then scheduled for their first laboratory appointment between 8:00 a.m and 9:00 am on a weekday. Testing was done in the morning to control for circadian rhythms and to keep the fasting period to a minimum. In addition to abstaining from eating and drinking (with the exception of water) for 12 hours prior to testing, participants were instructed not to smoke or engage in any strenuous exercise. They were also asked to refrain from the use of drugs or alcohol 24 hours prior. Once participants provided written consent, anthropomorphic data (weight, height, and waist circumference) were obtained. Participants then underwent a blood draw, followed by a structured interview in which additional demographic and medical information were collected. The electrodes for electrocardiographic (ECG) monitoring were attached in a bipolar configuration to the lower side of the participants’ rib cage, while a ground electrode was placed under the right clavicle. The ECG was obtained using PowerLab (ADInstruments, Oxford, UK). A Finopres Finometer (Amsterdam, The Netherlands) was placed on the middle finger of the participant’s non-dominant hand to measure blood pressure (BP). A thoracic belt was also secured around the participant’s thorax to measure respiration rate. Participants then completed some brief psychological questionnaires, which enabled them to acclimate to testing equipment before participating in the stress protocol. The stress protocol involved a 5 minute baseline period and two 5 minute psychological stressors: the Paced Auditory Serial Addition Test (PASAT) and a debate task. Each stressor was followed by a 5 min recovery period. Participants completed measures of affect, arousal, and stress perceptions before and after each stressor task. ECG, BP, and respiration were recorded continuously throughout the baseline, stress, and recovery periods. Following the stress protocol, participants completed additional questionnaires for purposes not covered in this manuscript. This study was approved by the Research and Ethics Board of the Montreal Heart Institute.

Randomization was performed by an independent biostatistician using a random sequence generator.

Randomization was performed at the individual level, stratified by sex and autonomic response to stress

No

Randomization was performed at the individual level with 19 participants; randomization was stratified by sex and autonomic stress response

Randomization was performed at the individual level with 19 participants; randomization was stratified by sex and autonomic stress response

Waitlist control group, n=10
MBSR intervention group, n=9

As feasibility and acceptability were the primary aims of the study, no power calculation was performed.