Stage 1 study sample description

Participants in the main trial were recruited and assessed during 2016–2017. Most participants were recruited via flyers and recruitment cards distributed throughout Rhode Island and Massachusetts (43% of participants), family/friend referrals (19%), former/current participant referrals (16%), and referrals from primary care practitioners or other health care professionals (16%).

Inclusion criteria were: (1) Hypertension/prehypertension (SBP≥120 mmHg systolic or DBP ≥80 mmHg or prescribed antihypertensive medication for treatment of hypertension); (2) Able to speak, read, and write in English; (3) All adults (≥18 years of age), genders and racial/ethnic groups were eligible to be included.

Exclusion criteria were: (1) Current regular meditation practice (>once/week); (2) serious medical illness precluding regular class attendance; (3) current substance abuse, suicidal ideation, or eating disorder; or (4) history of bipolar or psychotic disorders or self-injurious behaviors. These participants were excluded following standard guidelines because of risk for disrupting group participation, requiring additional or specialized treatment beyond capacity of this study, or already participating in practices similar to the intervention [20]. The study protocol was approved by the institutional review board at Brown University (protocol #1412001171 on September 3, 2015. Participants provided informed consent. Data were collected as part of the MB-BP Study (Clinicaltrials.gov #NCT02702258), described in more detail elsewhere [5].

The qualitative study

Purposive sampling of intervention participants was used to recruit for the qualitative study [21]. Intervention study participants were contacted by members of the research team to assess their willingness to participate. Participation was voluntary and independent of participation in the intervention trial. All study participants who completed the MB-BP program (n = 48) were eligible to participate.

First, three focus group discussions (FGDs) were conducted including 19 participants (FGD 1, n = 4; FGD 2, n = 8; FGD 3, n = 7). The FGDs were conducted by a co-author (AH), an experienced qualitative researcher, assisted by a note taker (AW). Neither had a relationship with protocol development, implementation, intervention assessments, or contact with participants prior to the FGD. The FGDs were audio recorded and held in a private room at the Brown University School of Public Health in Providence, RI. FGDs occurred within two months after completion of the intervention. Each session lasted between 1.5–2 hours and was conducted in accordance with an approved focus group protocol see S1 File.

FGD participants were provided with food and refreshments but were not compensated for participation.

Seven semi-structured, in-depth interviews (IDIs) were conducted with participants who declined participating in the focus group discussions, in order to foster a more representative sample, and to more effectively capture individual perspectives and experiences with the intervention [19]. They were selected using a randomized list of possible candidates by a senior member of the research staff. Those selected were then followed up to inquire about whether they would be willing to participate in an in-depth interview. Ten participants were contacted with three refusals in order to recruit the seven individuals included in the IDIs. All of the IDIs were conducted by phone, by a senior member of the research team (WN). Participants were reimbursed with a gift card ($25) for participating in the 25-minute IDI.

In-depth interviews (IDI)

The IDIs were conducted by a member of the study staff trained in qualitative methods under the guidance of the consulting qualitative expert (AH). The researcher conducting the interviews was familiar with MBPs and interested in conducting and evaluating MBPs. The interviews were conducted using Zoom (Version # 4.1.24407.0507, San Jose, CA.) software and audio recorded. The interviews were conducted in accordance with an approved protocol see S2 File.

Intervention description

This study adapted Mindfulness-Based Stress Reduction (MBSR) for participants with prehypertension/hypertension, creating MB-BP. Specifically, MB-BP is based on, and time-matched to, the standardized MBSR intervention which consists of eight 2.5-hour weekly group sessions, and a 7.5-hour one-day sessions, and is described elsewhere [5, 22–25]. MB-BP and MBSR contain similar instruction and practices in mindfulness meditation and conversations about stress and coping.

The unique areas of MB-BP are education on hypertension risk factors, hypertension health effects, and specific mindfulness modules focused on awareness of diet, physical activity, medication adherence, alcohol consumption, stress, and social support for behavior change. MB-BP builds a foundation of mindfulness skills (e.g. meditation, yoga, self-awareness, attention control, emotion regulation; Fig 1) through the modified MBSR curriculum. MB-BP then directs those skills towards participants’ relationship with their risk factors for hypertension. Details concerning study design, intervention assessments, and preliminary acceptability and feasibility results as well as customizations of MB-BP from MBSR are found in further detail elsewhere [17]. The curriculum guide and MB-BP instructor certification program can be accessed by contacting the principal investigator (EL).

Data analytical approach

Trained research assistants reviewed audio recordings and transcribed recordings verbatim. The data was collected as part of a larger mixed methods study and was analyzed using thematic analysis [5, 26–28]. Thematic analysis was considered the most appropriate analytical approach for the semi-structured data from the focus group discussion and in-depth interviews.

Both FGD and IDI transcripts were double-coded by two members of the research team who then identified both a priori and emergent codes by two members of the research team (WN, JW) using NVivo v.11 [27, 28]. Cross checks for coding consistency were performed by a third member of the research team (AW). Codes with definitions are listed in the qualitative codebook (see S1 Table). The data are available from the corresponding author upon request with ethics approval.

The team met under the supervision of the qualitative expert (AH) during a series of three in-person meetings to: (1) cluster FGD coding into broad themes, (2) discuss themes and additional qualitative work needed, and (3) refine FGD and IDI themes into main themes and sub-themes. During the iterative process of data analysis for the FGDs, the team found that saturation had not been achieved. In-depth interviews were planned to gain further insights into the main research questions, as well as to gain an individual perspective to enhance the group-based collective understanding of the FGDs. Videoconference- and phone-based IDI’s provide an additional benefit to reduce possible biases associated with focus group participation, where it is plausible that those who had less positive experiences in the MB-BP course may have declined coming to the in-person focus groups [29]. In addition to the importance of the individual perspective gained from the IDIs, participant burden for phone/videoconference IDI’s is less and participation rates are higher, and so it was thought that this could provide a more representative sample overall [29, 30]. The coding structure from the FGD was used to inform the coding of the IDI's. Discrepancies were resolved through group consensus and communications between the coders (WN, AW, JW) and the qualitative expert (AH) with input from the content expert when applicable (EL). The results of this process and the integrated thematic analysis of qualitative data from both FGDs and IDIs are presented below.

Theme one: Breath awareness, followed by body awareness, were the mindfulness practices that participants used most in their daily lives

Participants reported using a variety of mindfulness practices. However, they used breath awareness most often. Some became aware of difficult physical sensations, and used the breath practice to reduce discomfort: “Being aware of how different things affect your body. I would see my hands and feel the tension and start to breath and calm myself down.”(F2) Another participant said that she believed that breath awareness could be used for specific physiologic change (e.g. lowered heart rate): “The awareness of breathing and being able to kind of lower my heart rate and relax. If I sit there and focus on it, it's been helpful.”(IDI4)

Breath awareness was also used regularly during the S-T-O-P practice. In this practice participants Stop a moment, Take a breath, Observe opening towards thoughts, emotions, physical sensations and then Proceed with an activity that will support an effective response to the experience. For one participant, “being able to control my breathing has been very helpful—like I think about, wait a minute, stop, there’s actually an exercise S-T-O-P. So I stop, take a deep breath, and regulate my breathing–I find it so helpful in life.”(F1) Another participant detailed how this practice helped her navigate complicated social relationships. The participant was able to respond to stressful events more effectively: “it’s changed how I interact with her in particular, um. I think that it’s huge you know–the fact that it could have that kind of effect on a relationship that, that I very much treasure […] it helps me stop and think about what I’m doing, and it’s been a positive experience for both of us.”(IDI3)

However, another participant indicated that the breath awareness alone was enough, and although he appreciated that S-T-O-P exercise, he used it less than the breath awareness: “I found those [breath awareness meditations] probably more helpful than the S-T-O-P.”(IDI2) Overall, breath awareness was the most frequently used mindfulness practice, and often within the S-T-O-P tool.

Body scanning was also widely used. One participant explained that she became aware of tension or physical sensations in specific areas of her body and this practice allowed her to notice and resolve tension in the moment: “realizing through the day when my jaw is clenched, and just can start the breathing and do the body scanning, and as I said at our group the other day, I can mentally shake my body out.”(F3) She also reported applying the body scan practices before bed to alleviate excessive tension. “Particularly at night when you’re trying to go to sleep, you realize your shoulders are up, your back is tight, your jaw is tight.” One participant stated that body scanning was particularly important, and she that it was a practice she relied “on all the time now… it worked.”(F13)

Another agreed, stating that becoming aware of the body was a critical practice they continue to use in their daily life: “the body scan, which I had not been exposed to before, is something that was the most… [pause]… it was the first thing that we did and it was the first thing that I remembered and which had a lasting effect and which I rely on all the time now.” (F10)

Theme two: Participants used these practices as a way of grounding in the moment, allowing them to emotionally regulate more effectively

The increase in self-awareness of their present moment allowed participants to emotionally regulate more effectively. Practices, like breath and body awareness, increased present moment awareness allowing participants to become more conscious of physiologic sensations (i.e. interoception). By recognizing the physical sensations and associated thoughts, they could stop and choose their response to a given set of circumstances. For example, a participant indicated that she used breath awareness when she was upset to reduce stress and her BP: “I feel like a combination of being more aware, you know you’re in the car sometimes and something, you know, gets you upset. Just being able to take a few deep breaths, which I think affect definitely, you know, helps to lower the blood pressure.”(F9)

She stated breath awareness provided space for her in present moment experience, allowing her to choose her response instead of reacting: “[I] would never pay attention before, now you’re in the moment. And you have control to a degree, you can get yourself together better, to react in a better way […] just take a deep breath, you know, a couple of deep breaths, and think about what’s going on right now and how can you react to it.”(F9)

Another outlined how awareness was a tool that allowed him to become aware of the stressful situation and choose how to work with resultant emotions, specifically anger: “the phrase was to be aware, I’m aware of my anger and all of that sort of relates into this tool of awareness that we have been given and all this sort of relates to the breath. So that you’re aware of that stress level and your able to say yea that’s stress and let’s step away and back from that stress to take care of yourself and relax.” (F4)

Theme three: Participants applied emotion regulation strategies to specific hypertension risk factors: Stress and dietary choices

Most often participants used emotion regulation strategies to respond more effectively to stress. The practices (e.g. self-kindness, breath awareness, body awareness) allowed them to feel “a lot sooner when you’d get stressed,”(F9) and choose an accepting response to the stressor rather “than get up and get all stressed out again. And then just think ‘Uh oh, I guess that’s just how life is,’ and now I realize, ‘No.’”(F9) Participants agreed that they had increased their abilities to choose a response to stress. For example, “it helped me just to be better and be more in the moment, and to stop.” and “It was helpful in terms of me becoming more self-aware, and especially breaking patterns of responses.”(F10) One participant indicated he often chose breath exercises, stating he is “more relaxed and aware of my doing breathing exercises. Also, I find that to be very helpful in reducing my stress level.”(IDI6) Another participant applied these exercises specifically to stress during traffic “while I'm driving to work, instead of that being like I have to hurry up and get there, like to try to do breathing exercises in the car and relax and not worry about the traffic.”(IDI4)

Participants also modified dietary choices as a result of increased emotion regulation. One participant was able to mitigate stress and make heathier dietary choices, which became easier to maintain for longer periods of time: “being conscious of what I eat and making responsible choices, and I’m still working on that one. And sometimes I could go through periods of several days or weeks being mindful of that.”(IDI7) This participant had been avoiding salt, but the practices helped to continue reducing salt intake: “I find it necessary to be making, healthful choices in what I’m eating.”(IDI7) Another saw change in his food choices, as well as other risk factors for hypertension, and stated, “[I] can feel when I’m elevated and feel like I’m super tense, and I can also really physically choose how to lower that–whether it’s running, you know, doing some physical exercise, breathing, meditating, yoga, you know, or what I eat.”(F5) However, he emphasized that the increased choices had most importantly changed how he looked at food: “the way I look at food in a lot of ways, and you know… There’s that hesitation, that moment like, ‘Oh, wait, I have a choice here, you know, maybe I won’t do that.’ And it’s given me more ability to do that.”(F5)

There was an indication by one participant of a higher level of awareness and self-kindness while eating healthy, versus unhealthy, foods: “reinforce thinking about how your body feels when you eat the foods that maybe aren’t making your body feel good, versus the foods that are more helpful.” (F6) Healthy eating affected one participant’s interpersonal relationships, allowing him to “notice on vacation when I had too much caffeine, and when I overate, that it influenced the way that I treated other people.”(F16)

In contrast another participant explained that increasing self-awareness may have led to higher stress. This participant “had a medical problem that surfaced just before it started that was bothering me a lot with my eye,” and indicated that “the breathing helped me calm down” in response to the stress, “but I don’t think it was enough to affect my blood pressure.”(F6) In fact, he noted that he was “a little scared though […] I really never thought I had a problem with my blood pressure.” However, as a result of meditation, he “[paid] more attention to [BP], which I think I just ignored before. So it was a little upsetting to me.”(F6) This participant found mindfulness practices useful (e.g. breath awareness previous statement) but the program increased awareness of having “a problem [hypertension]” which was difficult to come to terms with: “I initially said I wanted to do it [the MB-BP program] to learn about mindfulness, but then all of the sudden it felt like I was acknowledging I had a problem about something, and it was upsetting to me to have a problem. So I think it’s going to take time to improve my blood pressure.”(F6)

Overall Summary. For many participants the program led to important changes in their health behaviors after becoming more self-aware and for some these changes were made in multiple areas of their lives. This is best captured by one participant who described how she was able to exert greater control over her life, stress responses, eating behaviors, and anxiety to lower her BP: “Being mindful of what makes us anxious and trying to control our reaction to what makes us anxious and, in addition, we were also taught to be mindful of what makes us happy. So, to reinforce different things that make you happy, and also with the eating, reinforce thinking about how your body feels when you eat the foods that maybe aren’t making your body feel good versus the foods that are more helpful. So, I think it affected everything in my whole life.”(F2).

In summary, participants indicated that the program impacted their cardiovascular health directly through becoming more aware of their present moment experiences, allowing them to make positive choices for their health behaviors, specifically minimizing stress reactivity and making healthier choices concerning their diet.