The utility of home blood pressure load in predicting average self-measured blood pressure.

OBJECTIVES: Average values for self-measured blood pressure (SMBP) more accurately reflect a patient's risk of cardiovascular disease than do office measurements. Oftentimes, however, patients provide lists of individual home blood pressure (BP) measurements, and average values cannot be computed within the time constraints of a clinic visit. In contrast, the home BP load - defined as the proportion of BP values greater than a partition value (e.g., 130 mmHg) - can be easily calculated. We examined the utility of the BP load in predicting the mean SMBP and confirming elevated SMBP. METHODS: Four hundred twenty untreated adults at least 30 years of age acquired SMBP data twice in the morning and twice in the evening over 10 days. The 'true' SMBP was defined as the mean of these 40 determinations. RESULTS: Using all 10 days of BP data and a systolic BP threshold of 130 mmHg, the average SMBP associated with a home BP load of 0.50 was 130 mmHg, with a 95% prediction interval of 126-133 mmHg. True systolic SMBP was approximately 6 mmHg lower and higher at home BP loads of 0.25 and 0.75, respectively. There was a 90% probability that the true systolic SMBP was greater than 130 mmHg if the systolic home BP load was at least 0.60. Corresponding values for 3 days and 1 day of SMBP were at least 0.68 and at least 0.84, respectively. CONCLUSION: Our analysis demonstrates that the home BP load can be used to estimate the average BP acquired on home monitoring and confirm elevated SMBP.

Hypertension-mediated organ damage in masked hypertension.

OBJECTIVES: Masked hypertension - a blood pressure (BP) phenotype characterized by a clinic BP in the normal range but elevated BP outside the office - is associated with early hypertension-mediated organ damage. This study examined early target organ manifestations of masked hypertension diagnosed by home (HBPM) and ambulatory (ABPM) BP monitoring. METHODS: Left ventricular (LV) structure and diastolic function measured by echocardiography, microalbuminuria, and coronary artery calcification were evaluated in 420 patients with high clinic BP (SBP 120-150 mmHg or DBP 80-95 mmHg). Evidence of hypertension-mediated organ damage was compared in patients with sustained normotension, masked hypertension, and sustained hypertension based on measurements by HBPM, daytime ABPM, and 24-h ABPM. RESULTS: The 420 participants averaged 48 (12) [mean (SD)] years of age; the average clinic BP was 130 (13)/81 (8) mmHg. In individuals with masked hypertension diagnosed by HBPM, indexed LV mass, relative wall thickness, and e' and E/e' (indices of LV relaxation), were generally intermediate between values observed in normotensives and sustained hypertensive patients, and were significantly greater in masked hypertension than normotensives. Similar trends were observed when masked hypertension was diagnosed by ABPM but a diagnosis of masked hypertension was not as reliably associated with LV remodeling or impaired LV relaxation in comparison to normotensives. There were trends towards greater likelihoods of detectable urinary microalbumin and coronary calcification in masked hypertension than in normotensives. CONCLUSION: These results support previous studies demonstrating early hypertension-mediated organ damage in patients with masked hypertension, and suggest that HBPM may be superior to ABPM in identifying patients with masked hypertension who have early LV remodeling and diastolic LV dysfunction.

Physical activity calorie expenditure (PACE) labels in worksite cafeterias: effects on physical activity.

BACKGROUND: Regular physical activity is an important component of healthy living and wellbeing. Current guidelines recommend that adults participate in at least 150 min of moderate or vigorous-intensity physical activity weekly. In spite of the benefits, just over half of U.S. adults meet these recommendations. Calorie-only food labels at points of food purchase have had limited success in motivating people to change eating behaviors and increase physical activity. One new point of purchase approach to promote healthy behaviors is the addition of food labels that display the physical activity requirement needed to burn the calories in a food item (e.g. walk 15 min). METHODS: The Physical Activity Calorie Expenditure (PACE) Study compared activity-based calorie-expenditure food labels with calorie-only labels at three Blue Cross and Blue Shield of North Carolina worksite cafeterias. After 1 year of baseline data collection, one cafeteria had food items labeled with PACE labels, two others had calorie-only food labels. Cohort participants were asked to wear an accelerometer and complete a self-report activity questionnaire on two occasions during the baseline year and twice during the intervention year. RESULTS: A total of 366 study participants were included in the analysis. In the PACE-label group, self-reported physical activity increased by 13-26% compared to the calorie-only label group. Moderate-to-vigorous physical activity (MVPA) increased by 24 min per week in the PACE-label group compared to the calorie-label group (p = 0.06). Changes in accelerometer measured steps, sedentary time, and MVPA had modest increases. Change ranged from 1 to 12% with effect size values from 0.08 to 0.15. Baseline physical activity level significantly moderated the intervention effects for all physical activity outcomes. Participants in both label groups starting in the lowest tertile of activity saw the largest increase in their physical activity. CONCLUSION: Results suggest small positive effects for the PACE labels on self-reported and objective physical activity measures. Minutes of weekly MVPA, strength training, and exercise activities showed modest increases. These results suggest that calorie-expenditure food labels may result in some limited increases in physical activity.

Effect of calories-only vs physical activity calorie expenditure labeling on lunch calories purchased in worksite cafeterias.

BACKGROUND: Calorie labeling on restaurant menus is a public health strategy to guide consumer ordering behaviors, but effects on calories purchased have been minimal. Displaying labels communicating the physical activity required to burn calories may be a more effective approach, but real-world comparisons are needed. METHODS: In a quasi-experimental study, we examined the effect of physical activity calorie expenditure (PACE) food labels compared to calorie-only labels on point-of-decision food purchasing in three worksite cafeterias in North Carolina. After a year of quarterly baseline data collection, one cafeteria prominently displayed PACE labels, and two cafeterias prominently displayed calorie-only labels. Calories from foods purchased in the cafeteria during lunch were assessed over 2 weeks every 3 months for 2 years by photographs of meals. We compared differences in purchased calorie estimates before and after the labeling intervention was introduced using longitudinal generalized linear mixed model regressions that included a random intercept for each participant. RESULTS: In unadjusted models comparing average meal calories after vs before labeling, participants exposed to PACE labels purchased 40.4 fewer calories (P = 0.002), and participants exposed to calorie-only labels purchased 38.2 fewer calories (P = 0.0002). The small difference of 2 fewer calories purchased among participants exposed to PACE labeling vs calorie-only labeling was not significant (P = 0.90). Models adjusting for age, sex, race, occupation, numeracy level, and health literacy level did not change estimates appreciably. CONCLUSION: In this workplace cafeteria setting, PACE labeling was no more effective than calorie-only labeling in reducing lunchtime calories purchased.

Association of ambulatory blood pressure variability with coronary artery calcium.

Blood pressure (BP) variability is associated with progression to clinical atherosclerosis. The evidence is inconclusive if BP variability predicts cardiovascular outcomes in low-risk populations. The aim of this study was to analyze the association of 24-hour BP variability with coronary artery calcium (CAC) among a group of individuals without coronary artery disease. The Masked Hypertension Study targeted patients with borderline high BP (120-149 mm Hg systolic and/or 80-95 mm Hg diastolic). Ambulatory blood pressure monitoring (ABPM) was performed at two time-points, 8 days apart. CAC was measured at exit visit via cardiac CT and reported as Agatston Score. Weighted standard deviations and average real variability were calculated from ABPM. Of the 322 participants who underwent cardiac CT, 26% (84) had CAC present, 52% (168) were female, and 21% (64) were black. BP variability did not differ by CAC group. In this low cardiovascular risk group, CAC was not associated with 24-hour ambulatory BP variability.

Effects of physical activity calorie expenditure (PACE) labeling: study design and baseline sample characteristics.

BACKGROUND: Obesity and physical inactivity are responsible for more than 365,000 deaths per year and contribute substantially to rising healthcare costs in the US, making clear the need for effective public health interventions. Calorie labeling on menus has been implemented to guide consumer ordering behaviors, but effects on calories purchased has been minimal. METHODS: In this project, we tested the effect of physical activity calorie expenditure (PACE) food labels on actual point-of-decision food purchasing behavior as well as physical activity. Using a two-group interrupted time series cohort study design in three worksite cafeterias, one cafeteria was assigned to the intervention condition, and the other two served as controls. Calories from food purchased in the cafeteria were assessed by photographs of meals (accompanied by notes made on-site) using a standardized calorie database and portion size-estimation protocol. Primary outcomes will be average calories purchased and minutes of moderate to vigorous physical activity (MVPA) by individuals in the cohorts. We will compare pre-post changes in study outcomes between study groups using piecewise generalized linear mixed model regressions (segmented regressions) with a single change point in our interrupted time-series study. The results of this project will provide evidence of the effectiveness of worksite cafeteria menu labeling, which could potentially inform policy intervention approaches. DISCUSSION: Labels that convey information in a more readily understandable manner may be more effective at motivating behavior change. Strengths of this study include its cohort design and its robust data capture methods using food photographs and accelerometry.

The Reproducibility of Racial Differences in Ambulatory Blood Pressure Phenotypes and Measurements.

BACKGROUND: We examined the reproducibility of differences in ambulatory blood pressure (BP) monitoring (ABPM) phenotypes and other parameters (sustained hypertension, masked hypertension, nocturnal hypertension, and nondipping) between African Americans and Whites. METHODS: A total of 420 participants untreated for hypertension attended 2 research visits 1 week apart during which traditional office BP averages and ABPM session averages were determined. We computed percent agreement in ABPM phenotypes across the 2 visits stratified by race and associated kappa statistics with 95% confidence intervals. RESULTS: Whites on average were older, more likely to be male, and had a higher body mass index. There was no significant difference in sleep quality as defined by sleep diary between the 2 races. There were also no significant differences between races in the proportions of participants with sustained hypertension, sustained normotension, or masked hypertension at either testing session. The prevalence of nocturnal hypertension was 59% vs. 75% (P = 0.012) at session 1 and 59% vs. 73% (P = 0.024) at session 2 for Whites and African Americans, respectively, with moderate reproducibility for both (kappas 0.45 and 0.44). Nocturnal BP nondipping had a prevalence 29% vs. 53% (P < 0.001) at session 1 and 29% vs. 47% (P = 0.004) at session 2 for Whites and African Americans, respectively, with fair reproducibility (kappas 0.28 and 0.29). CONCLUSIONS: Our findings support that African Americans indeed exhibit a greater preponderance of abnormal nocturnal BP patterns than Whites. Our work is some of the first to demonstrate that these abnormal patterns are modestly reproducible.

Examination of Several Physiological and Psychosocial Factors Potentially Associated With Masked Hypertension Among Low-Risk Adults.

The authors examined the association of factors, in addition to prehypertensive office blood pressure (BP) level, that might improve detection of masked hypertension (MH), defined as nonelevated office BP with elevated out-of-office BP average, among individuals at otherwise low risk. This sample of 340 untreated adults 30 years and older with average office BP <140/90 mm Hg all had two sets of paired office BP measurements and 24-hour ambulatory BP monitoring (ABPM) sessions 1 week apart. Other than BP levels, the only factors that were associated (at P<.10) with MH at both sets were male sex (75% vs 66%) and working outside the home (72% vs 59% for the first set and 71% vs 45% for the second set). Adding these variables to BP level in the model did not appreciably improve detection of MH. No demographic, clinical, or psychosocial measures that improved upon prehypertension as a potential predictor of MH in this sample were found.

Comparison of patients' confidence in office, ambulatory, and home blood pressure measurements as methods of assessing for hypertension.

OBJECTIVE: Uncertainty exists when relying on office (clinic) blood pressure (BP) measurements to diagnose hypertension. Home BP monitoring and ambulatory BP monitoring (ABPM) provide measurements that are more strongly associated with cardiovascular disease. The degree to which patients exhibit uncertainty about office BP measurements is unknown, as is whether they would have less uncertainty about other BP measurement methods. We therefore assessed people's confidence in methods of BP measurement, comparing perceptions about office BP monitoring, home BP monitoring, and ABPM techniques. METHODS: We surveyed adults who were 30 years or older (n=193), all whom had undergone office BP measurements, two sessions of 24-h ABPM, and two 5-day periods of home BP monitoring. Respondents were asked to indicate their level of confidence on a 1 to 9 scale that BP measurements represented their 'usual' BP. RESULTS: Respondents had least confidence that assessments of BP made by office measurements (median 6) represented usual BP and greater confidence that assessments made by home BP monitoring (median 7, P<0.0001 vs. office) and ABPM (median 8, P<0.0001 vs. office) did so. Confidence levels did not vary significantly by BP levels, age, sex, race, or education level. CONCLUSION: The finding that patients do not have a great deal of confidence in office BP measurements, but have a higher degree of confidence in home BP and ambulatory BP assessment methods may be helpful in guiding strategies to diagnose hypertension and improve antihypertensive medication adherence.

Levels of office blood pressure and their operating characteristics for detecting masked hypertension based on ambulatory blood pressure monitoring.

BACKGROUND: Masked hypertension (MH)--nonelevated office blood pressure (BP) with elevated out-of-office BP average--conveys cardiovascular risk similar to or approaching sustained hypertension, making its detection of potential clinical importance. However, it may not be feasible or cost-effective to perform ambulatory BP monitoring (ABPM) on all patients with a nonelevated office BP. There likely exists a level of office BP below which ABPM is not warranted because the probability of MH is low. METHODS: We analyzed data from 294 adults aged ≥ 30 years not on BP-lowering medication with office BP <140/90 mm Hg, all of whom underwent 24-hour ABPM. We calculated sensitivity, false-positive rate, and likelihood ratios (LRs) for the range of office BP cutoffs from 110 to 138 mm Hg systolic and from 68 to 88 mm Hg diastolic for detecting MH. RESULTS: The systolic BP cutoff with the highest +LR for detecting MH (1.8) was 120 mm Hg, and the diastolic cutoff with the highest +LR (2.4) was 82 mm Hg. However, the systolic level of 120 mm Hg had a false-positive rate of 42%, and the diastolic level of 82 mm Hg had a sensitivity of only 39%. CONCLUSIONS: The cutoff of office BP with the best overall operating characteristics for diagnosing MH is approximately 120/82 mm Hg. However, this cutoff may have an unacceptably high false-positive rate. Clinical risk tools to identify patients with nonelevated office BP for whom ABPM should be considered will likely need to include factors in addition to office BP.

Reproducibility of masked hypertension among adults 30 years or older.

OBJECTIVE: Masked hypertension (MH) refers to nonelevated office blood pressure (BP) with elevated out-of-office BP, but its reproducibility has not been conclusively established. We examined 1-week reproducibility of MH by home BP monitoring (HBPM) and ambulatory BP monitoring (ABPM). METHODS: We recruited 420 adults not on BP-lowering medication, with recent clinic BP between 120/80 and 149/95 mmHg. For main comparisons, participants with office average less than 140/90 mmHg were considered to have MH if awake ABPM average was 135/85 mmHg or higher; they were considered to have MH by HBPM if the average was 135/85 mmHg or higher. Percentage agreements were quantified in terms of κ. We also examined the prevalence of MH, defined as office average less than 140/90 mmHg, with a 24-h ABPM average of 130/80 mmHg or higher. We carried out sensitivity analyses using different threshold BP levels for ABPM-office pairings and HBPM-office pairings for defining MH. RESULTS: Prevalence rates of MH based on office-awake ABPM pairings were 44 and 43%, with an agreement of 71% (κ=0.40; 95% confidence interval 0.31-0.49). MH was less prevalent (15 and 17%) using HBPM-office pairings, with agreement of 82% (κ=0.30; 95% confidence interval 0.16-0.44), and more prevalent when considering the 24-h average (50 and 48%). MH was also less prevalent when more stringent diagnostic criteria were applied. Office-HBPM pairings and office-awake ABPM pairings had fair agreement on MH classification on both occasions, with κ-values of 0.36 and 0.30. CONCLUSION: MH has fair short-term reproducibility, providing further evidence that for some people, out-of-office BP is systematically higher than that measured in the office setting.