Design and Sample
The SHIP-HBP study is a community-based, prospective trial involving middle-aged Korean American persons in the Baltimore-Washington metropolitan area. The trial's primary objective is to determine whether the SHIP-HBP is effective in controlling high BP at 3, 9, and 15 months from the start of the intervention. This multifaceted intervention has 3 main components: (1) a structured psychobehavioral education that focuses on fostering self-help skills in controlling high BP, (2) home BP monitoring with a telephone transmission system, and (3) telephone counseling by a bilingual nurse who facilitates problem solving in managing BP. The education component was offered for 6 weeks, followed by a 6-week test period for home BP monitoring. Home monitoring of BP and telephone counseling began 3 months after the start of the education intervention and lasted for 12 months. For the purposes of this paper, we used outcomes collected at 3 months, including behavioral indicators and BP outcomes measured before we started telephone counseling.
We used a stratified sampling scheme based on the participant's age and sex to create comparable groups of middle-aged Korean American persons with high BP who were representative of Korean American persons who reside in the Baltimore-Washington metropolitan area. Approximately 100,000 Korean American persons live in this region,37 of whom 23,000 are estimated to be in the target age group (40–65 years), and 41.7% are assumed to have high BP.38,39 The eligibility criteria were (1) self-identified as a first-generation Korean American, (2) 40 to 64 years of age, and (3) systolic BP (SBP) ≥140 and/or diastolic BP (DBP) ≥90 mm Hg or taking BP medication. At baseline, 445 Korean American persons were recruited primarily from ethnic Korean churches, grocery stores, and ethnic newspaper advertisements.37 Of those completing the baseline assessment, 65 dropped out either before the education sessions ended or before completing follow-up data collection at 3 months or did not measure and transmit their BP at home. The reasons for dropping out included lost contact, travel, moving, schedule conflict, personal problem, physical condition, normal BP, belief that their BP was not high enough to require rigorous management, and overwhelmed with assigned BP measurement. There were no significant differences in sociodemographic characteristics between patients who remained in the study and those who dropped out.
On institutional review board approval, eligible Korean Americans with high BP who agreed to participate in this study were assessed for baseline characteristics. Trained research staff measured BP, body weight, and height, and questionnaires were completed by self-report. Participants needed 20 to 40 minutes to complete the baseline questionnaire. They were then assigned to either the in-class education group (n=184) or the mail education group (n=261), considering such factors as place of residence (ie, proximity to our in-class locations), schedule compatibility (with our 21 classes in several locations at different times), and participant preference. We were particularly careful to monitor the assignment to obtain compatible groups as well as to minimize potential crossover effect within a relatively small social network (eg, attending the same church) between intervention groups. For example, when a group of participants were identified at a church, one mode of education was offered to the church members. At baseline, the in-class intervention and mail intervention groups did not significantly differ in terms of sociodemographic or medical characteristics. Altogether, 380 participants (in-class group, 168; mailing group, 212) completed the 3-month follow-up assessments and BP measurements, and they were included in the analysis.
The mailing intervention group received weekly 2-hour in-class education sessions over 6 weeks. The group intervention classes were held in a community center located in Korean American-populated neighborhoods. The self-paced mailing intervention group received the same educational materials each week for 6 weeks via regular mail. Of those in the in-class intervention group (n=168), 86 (51.2%) attended all 6 class sessions, while the remainder attended 1 to 5 sessions (mean number of sessions attended, 5.08±1.25). During the 6-week education for the in-class intervention group and on completion of the 6-week education for the mailing intervention group, study participants were given a home-based BP measurement device (A&D UA-767; A&D Company, Ltd, Tokyo, Japan) equipped with a telephone transmission system (HBPMT) and instructions. During the following 6-week testing period, participants were instructed to measure their BP at home using the device and start transmitting BP data once a week via their home telephone; this process generally took <2 minutes per transmission. The purpose of this test period was to increase the participants' level of confidence in measuring their BP and transmitting the data and to prepare them for the next 12-month telephone counseling phase, which would build on the patient's progress in BP control through tailored messages from a bilingual registered nurse.
Psychobehavioral Education Intervention
Our psychobehavioral education intervention in this ongoing study has 2 main components: the first, an educational and behavioral intervention, is aimed at enhancing clients' knowledge of high BP and its treatment, reducing risk factors, and providing resources to Korean American persons; it also focuses on improving Korean Americans' coping/enabling skills in problem solving, cognitive reframing, and belief in self. The second component, the psychological intervention, is aimed at assisting them in reframing life adversity in a different and positive perspective. The activities of the psychosocial intervention are centered around (1) introducing and enhancing strategies for managing life adversities that are inherent in the experience of having high BP and being a middle-aged immigrant, (2) providing necessary knowledge or/and information, and (3) promoting self-care behaviors related to high BP control.
All study variables were measured twice (at baseline and 3 months), except for the ongoing monitoring of BP. Research questionnaires used in this study were developed in English and translated into Korean, then back-translated into English. In this study, participants exclusively used the Korean version because they were all born in Korea and preferred using their mother tongue.
Baseline BP was measured by averaging the second and third BP readings, recorded in mm Hg. Measurements of DBP and SBP were obtained by trained research assistants using the A&D UA-767, a fully automatic device based on the oscillometric method. We chose not to use mercury sphygmomanometers because of the major measurement issue of interobserver and intraobserver variability, as highlighted in 2 recently published articles.40,41 Instead, we chose the A&D UA-767 device, which had been previously validated against a mercury sphygmomanometer.42 The same device, with an additional t n function, was used for HBPMT.
Follow-up BP measurements were collected by HBPMT, measured at home with the same A&D UA device. During this intervention trial, participants were asked to measure their BP at least 3 times in the morning and 3 times in the evening each week. For the HBPMT test period (6 weeks following the 6-week education intervention), self-monitoring of BP was validated by automated BP reports from HBPMT, which showed the time and frequency of BP measurements and BP readings. We used the weekly average of those transmitted data as postintervention data.
High BP belief was measured by the high BP belief scale.43 High BP beliefs were assessed by a 12-item questionnaire, which asked participants to indicate whether they believed certain behavioral factors could help lower BP and to select the most important factor to control BP. Higher scores represent higher levels of high BP belief. This scale has been translated into Korean and was used in our previous study of Korean American persons with high BP,37 with an α coefficient of .897 in the present study.
Self-efficacy for high BP control was measured by a high BP management self-efficacy scale, adapted from the high BP belief scale.43 The modified scale consists of 4-point Likert-type items asking how confident the individual is in managing high BP in 11 areas, including reducing salt intake, taking prescribed BP medicines, and eating fewer fatty foods. Higher scores represent higher levels of self-efficacy in managing high BP. The Korean version yielded an a coefficient of .93 for the present sample.
High BP knowledge was evaluated using 12 items developed by the National High Blood Pressure Education Program of the National Heart, Lung, and Blood Institute (1994), with the addition of 18 items generated by the current investigative team on the basis of a literature review. This modified instrument has been used in our work with Korean American persons.9 High BP knowledge scores were calculated by counting the number of items with correct responses to statements such as “Young adults don't get high BP” and “High BP is life-threatening.” Scores ranged from 0 to 30.
Medication adherence was measured by the medication subscale from the Hill-Bone Compliance Scale.44 The scale consists of nine 4-point Likert-type items (1 = none of the time, 2 = some of the time, 3 = most of the time, 4 = all the time) that measure the reported degree of adherence to medication. Higher scores indicate lower adherence. This scale has demonstrated adequate reliability (α = .74–.84), construct validity, and predictive validity in African American and non-Hispanic white patients.44 Cronbach α was .74 for the medication subscale in this sample.