Masked hypertension, a review of the literature

Masked phenomenon: renal and cardiovascular complications; review and updates

BACKGROUND

In the in-clinic blood pressure (BP) recording setting, a sizable number of individuals with normal BP and approximately 30% of patients with chronic renal disease (CKD) exhibit elevated outpatient BP records. These individuals are known as masked hypertension (MHTN), and when they are on antihypertensive medications, but their BP is not controlled, they are called masked uncontrolled hypertension (MUHTN). The masked phenomenon (MP) (MHTN and MUHTN) increases susceptibility to end-organ damage (a two-fold greater risk for cardiovascular events and kidney dysfunction). The potential extension of the observed benefits of MP therapy, including a reduction in end-organ damage, remains questionable.

AIM AND METHODS

This review aims to study the diagnostic methodology, epidemiology, pathophysiology, and significance of MP management in end-organs, especially the kidneys, cardiovascular system, and outcomes. To achieve the purposes of this non-systematic comprehensive review, PubMed, Google, and Google Scholar were searched using keywords, texts, and phrases such as masked phenomenon, CKD and HTN, HTN types, HTN definition, CKD progression, masked HTN, MHTN, masked uncontrolled HTN, CKD onset, and cardiovascular system and MHTN. We restricted the search process to the last ten years to search for the latest updates.

CONCLUSION

MHTN is a variant of HTN that can be missed if medical professionals are unaware of it. Early detection by ambulatory or home BP recording in susceptible individuals reduces end-organ damage and progresses to sustained HTN. Adherence to the available recommendations when dealing with masked phenomena is justifiable; however, further studies and recommendation updates are required.

Masked pregnancy-associated hypertension as a predictor of adverse outcomes

BACKGROUND

Masked hypertension has been described in nonpregnant populations as elevated blood pressure in the home setting that is not reproduced on clinical assessment. Patients with masked hypertension have a greater risk of cardiovascular morbidity than patients who have blood pressures within normal range or those with white coat hypertension.

OBJECTIVE

This study aimed to determine whether masked pregnancy-associated hypertension detected on Connected Maternity Online Monitoring, a remote home blood pressure monitoring system, is associated with higher rates of hypertensive disorders of pregnancy during delivery admission and maternal and neonatal morbidities.

STUDY DESIGN

This was a retrospective cohort study of all patients on Connected Maternity Online Monitoring who delivered at 6 hospitals in a single healthcare system between October 2016 and December 2020. Patients were classified as having either normal blood pressure or masked pregnancy-associated hypertension. Masked pregnancy-associated hypertension was defined as remotely detected systolic blood pressure of ≥140 mm Hg or diastolic blood pressure of ≥90 mm Hg after 20 weeks of gestation on 2 occasions before diagnosis in a clinical setting. The chi-square test and Student t test were used for demographic and outcomes comparisons. Logistic regression was used to adjust outcomes by race, insurance, and body mass index.

RESULTS

A total of 2430 deliveries were included in our analysis, including 165 deliveries that met the criteria for masked pregnancy-associated hypertension. Clinically established pregnancy-associated hypertension, defined at the time of delivery, was more common in the masked pregnancy-associated hypertension group than in the normotensive group (66% vs 10%; adjusted odds ratio, 17.2; 95% confidence interval, 11.91-24.81). Patients with masked pregnancy-associated hypertension had higher rates of preeclampsia with severe features on delivery admission than normotensive patients (28% vs 2%; adjusted odds ratio, 23.35; 95% confidence interval, 14.25-38.26). Preterm delivery (16% vs 7%; adjusted odds ratio, 2.47; 95% confidence interval, 1.55-3.94), cesarean delivery(38% vs 26%; adjusted odds ratio, 1.58; 95% confidence interval, 1.13-2.23), small for gestational age (11% vs 5%; adjusted odds ratio, 2.27; 95% confidence interval, 1.31-3.94), and neonatal intensive care unit admission (8% vs 4%; adjusted odds ratio, 2.20; 95% confidence interval, 1.18-4.09) were more common among patients with masked pregnancy-associated hypertension than among normotensive patients.

CONCLUSION

With more outcomes research, remote blood pressure monitoring may prove to be an important tool in identifying pregnancies at risk of complications related to masked hypertension.

The prevalence of masked hypertension in patients with lone atrial fibrillation: a cross sectional analytical study

Atrial fibrillation (AF) is prevalent in individuals with essential hypertension (HTN). Masked hypertension occurs in up to 15% of the general population and is associated with adverse clinical outcome. The aim of the current study was to evaluate the prevalence of masked hypertension in apparently normotensive individuals with lone AF. A cross sectional analytical study performed at the Rabin Medical Center included all patients > 18 years who visited the emergency department (ED) in the years 2018-2021 with idiopathic AF, had normal blood pressure (BP) values during their ED visit and did not have a history of hypertension or current use of anti-hypertensives. Ambulatory blood pressure monitoring (ABPM) was performed in all eligible patients within 30 days from ED visit. Data collected included information from the ED visit and data extracted from the monitoring device. A total of 1258 patients were screened for eligibility, of which 40 were included in the analysis. The average age was 53.4 ± 16 years, 28 patients (70%) were males. Overall, 18 individuals (46%) had abnormal BP values according to the 2017 ACC/AHA guidelines for the diagnosis of hypertension. Of these, 12 had abnormal 24-h BP average (≥ 125/75 mmHg), one had isolated daytime abnormal average (≥ 130/80 mmHg) and 11 had isolated night time abnormal average (≥ 110/65 mmHg). Masked hypertension is prevalent in patients with lone AF without a diagnosis of HTN and performing ABPM in such individuals should be strongly considered.

Assessment of hypertension in obstructive sleep apnea by ambulatory blood pressure monitoring: a systematic review and meta-analysis

Among obstructive sleep apnea (OSA) patients, there exists a high prevalence of hypertension. Determining the optimal blood pressure (BP) monitoring modality in this population will lead to a better understanding of hypertension profiles and a more accurate diagnosis of hypertension. PubMed, Ovid/Medline, Web of Science, Scopus, Cochrane Library, and CINAHL databases were screened, and the relevant articles regarding BP monitoring in OSA patient population were selected. Studies evaluating both ambulatory (ABPM) and office BP measurements were selected to be analyzed for the hypertension diagnosis specificity of ABPM measurement in OSA patients compared with office measurements. If reported, additional information regarding white-coat, masked hypertension, and circadian BP pattern prevalence was included. A cumulative analysis of five studies revealed a prevalence of hypertension based on BP to be 44%, whereas a cumulative analysis of four studies revealed a prevalence of hypertension based on ABPM to be 66%. Excluding a study with the nighttime assessment of hypertension reduced the cumulative prevalence of hypertension in OSA patients to 59%. The cumulative prevalence of Studies demonstrated the prevalence of masked and white-coat hypertension to be 34 and 9%, respectively. As a higher prevalence of hypertension was detected by ABPM and nighttime measurement, it can be deduced that ABPM is more sensitive in determining OSA patients with hypertension, and that nighttime ABPM further increases this sensitivity. The presence of masked and white-coat hypertension in OSA patients underlines the importance of correct hypertension diagnosis as it affects further management in this population with increased cardiovascular risk.

Smoking and overweight associated with masked uncontrolled hypertension: a Hypertension Optimal Treatment (HOT) Sub-Study

PURPOSE

The Hypertension Optimal Treatment (HOT) Study investigated the relationship between target office diastolic blood pressure (BP) ≤80, ≤85 or ≤90 mmHg and cardiovascular morbidity and mortality in 18,790 patients aged 50-80 years. The home BP sub-study enrolled 926 patients and the aim was to clarify whether the separation into the BP target groups in the office prevailed in the out-of-office setting. The present study aimed to identify variables that characterised masked uncontrolled hypertension (MUCH) and white coat uncontrolled hypertension (WUCH).

MATERIAL AND METHODS

The sub-study participants took their home BP when office BP had been up titrated. The cut-off for normal or high BP was set to ≥135/85 mmHg at home and ≥140/90 mmHg in the office. We analysed data by using multivariate and stepwise multivariate logistic regression with home and office BP combinations as the dependent variables.

RESULTS

WUCH was associated with lower body mass index (BMI) (odds ratio (OR) 0.92, 95% confident intervals (CIs) 0.88-0.96, p < 0.001). MUCH was associated with smoking (OR 1.89, 95% CIs 1.25-2.86, p = 0.0025) and with lower baseline heart rate (OR 0.98, 95% CIs 0.97-0.99, p = 0.03) and higher BMI (OR 1.03, CIs 1.00-1.06, p = 0.04). MUCH remained associated with smoking (OR 2.76, 95% CIs 1.76-4.35, p < 0.0001) also when using ≥140/90 mmHg as the cut-off for both home and office BP. MUCH was also associated with higher BMI (OR 1.05, 95% CIs 1.01-1.09, p = 0.009) while WUCH was associated with lower BMI (OR 0.93, 95% CIs 0.90-0.97, p = 0.0005) when using ≥140/90 mmHg as a cut-off.

CONCLUSION

Our data support that 'reversed or masked' treated but uncontrolled hypertension (MUCH) is common and constitutes about 25% of treated hypertensive patients. This entity (MUCH) is rather strongly associated with current smoking and overweight while uncontrolled white coat (office) hypertension (WUCH) is associated with lower BMI.

Long Working Hours and the Prevalence of Masked and Sustained Hypertension

Previous studies on the effect of long working hours on blood pressure have shown inconsistent results. Mixed findings could be attributable to limitations related to blood pressure measurement and the lack of consideration of masked hypertension. The objective was to determine whether individuals who work long hours have a higher prevalence of masked and sustained hypertension. Data were collected at 3-time points over 5 years from 3547 white-collar workers. Long working hours were self-reported, and blood pressure was measured using Spacelabs 90207. Workplace clinic blood pressure was defined as the mean of the first 3readings taken at rest at the workplace. Ambulatory blood pressure was defined as the mean of the next readings recorded every 15 minutes during daytime working hours. Masked hypertension was defined as clinic blood pressure < 140/90 mm Hg and ambulatory blood pressure ≥135/85 mm Hg. Sustained hypertension was defined as clinic blood pressure ≥140/90 mm Hg and ambulatory blood pressure ≥135/85 mm Hg or being treated hypertension. Long working hours were associated with the prevalence of masked hypertension (prevalence ratio 49+ =1.70 [95% CI, 1.09–2.64]), after adjustment for sociodemographics, lifestyle-related risk factors, diabetes mellitus, family history of cardiovascular disease, and job strain. The association with sustained hypertension was of a comparable magnitude (prevalence ratio 49+ =1.66 [95% CI, 1.15–2.50]). Results suggest that long working hours are an independent risk factor for masked and sustained hypertension. Workplace strategies targeting long working hours could be effective in reducing the clinical and public health burden of hypertension.

Telemonitoring of 24-Hour Blood Pressure in Local Pharmacies and Blood Pressure Control in the Community: The Templar Project

BACKGROUND

The analysis of ambulatory blood pressure monitorings (ABPMs) performed in 639 Italian pharmacies in the context of a telehealth-based service allowed to evaluate the level of blood pressure (BP) control in the community.

METHODS

Twenty-four-hour ABPMs were performed by a clinically validated, automated, upper-arm BP monitor. Recordings were uploaded on a certified web-based telemedicine platform (www.tholomeus.net) and remote medical reporting provided. In each subject, an automatic BP measurement was obtained in the pharmacy and clinical information collected before starting the ABPM.

RESULTS

A total of 20,773 subjects (mean age 57 ± 15 years; 54% females; 28% receiving antihypertensive medications, 31% with any cardiovascular [CV] risk factor) provided valid ABPMs. BP control was poor, but better in ambulatory conditions (24-hour BP <130/80 mm Hg 54% vs. pharmacy BP < 140/90 mm Hg 43%; P < 0.0001) and in drug-treated subjects. Sustained normotension was reported in only 28% subjects. Isolated nocturnal hypertension (16%; nighttime BP ≥120/70 mm Hg with normal daytime BP) was more common (P < 0.0001) than isolated daytime hypertension (9%; daytime BP ≥ 135/85 mm Hg with normal nighttime BP). Sustained hypertension (43%) was more common in younger males at the lowest CV risk, with daytime hypertension. White-coat hypertension (14%) was more common in females. Masked hypertension was not uncommon (15%) and more often observed in older males with an elevated nocturnal BP.

CONCLUSIONS

A telemedicine-based service provided to community pharmacies may facilitate access to ABPM, thus favoring a more accurate hypertension screening and detection. It may also help describe the occurrence of different 24-hour BP phenotypes and personalize the physician's intervention.

Psychosocial Stressors at Work and Ambulatory Blood Pressure

PURPOSE OF REVIEW

Psychosocial stressors at work from the demand-latitude and effort-reward imbalance models are adverse exposures affecting about 20-25% of workers in industrialized countries. This review aims to summarize evidence on the effect of these stressors on blood pressure (BP).

RECENT FINDINGS

Three systematic reviews have recently documented the effect of these psychosocial stressors at work on BP. Among exposed workers, statistically significant BP increases ranging from 1.5 to 11 mmHg have been observed in prospective studies using ambulatory BP (ABP). Recent studies using ABP have shown a deleterious effect of these psychosocial stressors at work on masked hypertension as well as on blood pressure control in pharmacologically treated patients. Evidence on the effect of these psychosocial stressors on BP supports the relevance to tackle these upstream factors for primary prevention and to reduce the burden of poor BP control. There is a need for increased public health and clinical awareness of the occupational etiology of high BP, hypertension, and poor BP control.

Masked hypertension incidence and risk factors in a prospective cohort study

Aims

Masked hypertension may affect up to 30% of the general population and is associated with a high cardiovascular disease risk. No previous study has examined the incidence of masked hypertension and its risk factors. The study aim was to determine the incidence of masked hypertension and to examine its related risk factors.

Methods

This is a cohort study including 1836 initially normotensive participants followed up on average for 2.9 years. Blood pressure was measured using Spacelabs 90207. Manual blood pressure was defined as the mean of the first three readings taken at rest. Ambulatory blood pressure was defined as the mean of the next readings recorded every 15 minutes during daytime working hours. Masked hypertension incidence at follow-up was defined as manual blood pressure less than 140 and less than 90 mmHg and ambulatory blood pressure at least 135 or at least 85 mmHg. Generalised estimating equations were used.

Results

The cumulative incidence of masked hypertension was 10.3% and was associated with male gender (relative risk (RR) 1.51, 95% confidence interval (CI) 1.18–1.94), older age (RR40–49 years 1.56, 95% CI 1.16–2.11, RR≥50 years 1.50, 95% CI 1.06–2.10), higher education (RRcollege 1.31, 95% CI 1.03–1.65), body mass index (RR≥27 1.43, 95% CI 1.11–1.85), smoking (RR 1.51, 95% CI 1.09–2.010) and alcohol intake (RR≥6/week 1.65, 95% CI 1.13–2.03).

Conclusion

The present study is the first to identify risk factors for the incidence of masked hypertension. Current guidelines for hypertension detection recommend ambulatory blood pressure in patients with an elevated blood pressure reading at the clinic. As it is impractical to measure ambulatory blood pressure in all normotensive patients, factors identified in the present study should be considered for the screening of at-risk individuals and for primary prevention of masked hypertension.

Masked hypertension and effort-reward imbalance at work among 2369 white-collar workers

Hypertension is an important risk factor of cardiovascular diseases, the leading cause of death worldwide. Adverse effects of psychosocial factors at work might increase the risk of masked hypertension, but evidences are still scarce. The objective of this study is then to determine whether adverse psychosocial work factors from the effort-reward imbalance (ERI) model are associated with the prevalence of masked hypertension in a population of white-collar workers. White-collar workers were recruited from three public organizations. Blood pressure was measured at the workplace for manually operated measurements (mean of the first three readings taken by a trained assistant) followed by ambulatory measurements (mean of all subsequent readings taken during the working day). Masked hypertension was defined as manually operated BP<140/90 mm Hg and ambulatory BP ⩾135/85 mm Hg. ERI exposure at work was measured using Siegrist's validated questionnaire. Blood pressure readings were obtained from 2369 workers (participation proportion: 85%). ERI exposure (OR: 1.53 (95% CI: 1.16-2.02) and high efforts at work (OR: 1.61 (95% CI: 1.13-1.29) were associated with masked hypertension, after adjusting for sociodemographic and cardiovascular risk factors. Workers exposed to an imbalance between efforts spent at work and reward had a higher prevalence of masked hypertension. High efforts at work might be of particular importance in explaining this association. Future studies should be designed to investigate how clinicians can include questions on psychosocial work factors to screen for masked hypertension and how workplace interventions can decrease adverse psychosocial exposures to lower BP.

Masked Hypertension: How to Identify and When to Treat?

Approximately one out of 7-8 individuals with normal blood pressure (BP) in the clinic or doctor's office and one third of patients with chronic kidney disease with normal clinic BP have elevated ambulatory BP (masked hypertension). Patients with masked hypertension have an increased risk for target organ damage and a two-fold increased risk for cardiovascular events compared to patients with normal clinic and ambulatory BP. Despite this elevated risk for adverse outcomes, patients with masked hypertension have been excluded from hypertension trials because of their normal clinic BP. It is still unknown whether the reduction in target organ damage and adverse cardiovascular outcomes associated with treatment of hypertension extends to patients with masked hypertension. Ongoing and planned interventional studies will provide an answer to this crucial question in a few years. At present, it seems reasonable to follow the suggestion of current European guidelines, that lifestyle measures and drug treatment should be considered in the presence of masked hypertension.

Persistence and progression of masked hypertension: a 5-year prospective study

Objectives. To examine masked hypertension persistence over 5 years. Methods. White-collar workers were recruited from three public organizations. Blood pressure (BP) was measured using Spacelabs 90207. Manually operated BP was defined as the mean of the first three readings taken at rest. Ambulatory BP was defined as the mean of the next readings taken every 15 minutes and recorded during working hours. BP was assessed three times over 5 years. Masked hypertension was defined as manually operated BP less than 140 and less than 90 mmHg and ambulatory BP at least 135 or at least 85 mmHg. Sustained hypertension was defined as manually operated BP at least 140 or at least 90 mmHg and ambulatory BP at least 135 or at least 85 mmHg or being treated for hypertension. Results. BP measurements were obtained from 1669 participants from whom 232 had masked hypertension at baseline. Persistence of masked hypertension was 38% and 18.5%, after 3 and 5 years, respectively. Progression to sustained hypertension was 26% and 37%, after 3 and 5 years, respectively. Conclusion. Among baseline masked hypertensives, one-third progressed to sustained hypertension and about one out of five remained masked after 5 years, potentially delaying diagnosis and treatment.

Effectiveness and safety of valsartan in children aged 6 to 16 years with hypertension

The effectiveness and safety of valsartan have not been assessed in hypertensive children. Therefore, hypertensive patients aged 6 to 16 years (n=261) were randomized to receive weight-stratified low- (10/20 mg), medium- (40/80 mg), or high-dose (80/160 mg) valsartan for 2 weeks. After 2 weeks, patients were randomized to a 2-week placebo-controlled withdrawal phase. Dose-dependent reductions in sitting systolic blood pressure (SSBP) and sitting diastolic blood pressure (SDBP) were observed after 2 weeks (low dose, -7.9/-4.6 mm Hg; medium dose, -9.6/-5.8 mm Hg; high dose, -11.5/-7.4 mm Hg [P<.0001 for all groups]). During the withdrawal phase, SSBP and SDBP were both lower in the pooled valsartan group than in the pooled placebo group (SSBP, -2.7 mm Hg [P=.0368]; SDBP, -3.0 mm Hg [P=.0047]). Similar efficacy was observed in all subgroups. Valsartan was well tolerated and headache was the most commonly observed adverse event during both the double-blind and 52-week open-label phases.

Exaggerated blood pressure response to exercise--a new portent of masked hypertension

Masked hypertension (MHT) is a popular entity with increased risk of developing sustained hypertension, heart attack, stroke, and death. Subjects have normal blood pressure (BP) at office but elevated values at night so it is difficult to diagnose. Exaggerated blood pressure response to exercise (EBPR) is also a predictor of future hypertension. To investigate the relationship between these two entities, we evaluated 61 normotensive subjects with EBPR. The subjects underwent 24-h ambulatory blood pressure monitoring (ABPM). The prevalence of masked hypertension among subjects with EBPR was 41%. Body mass index (BMI), non-high density lipoprotein (HDL) cholesterol, diastolic blood pressure (DBP) at peak exercise and recovery, nondipping DBP pattern, and elevated early morning average BPs were associated with masked hypertension. In multivariate logistic regression analysis, the DBP measured at peak exercise was detected as an independent predictor of MHT in subjects with EBPR. Subjects with abnormally elevated BP during exercise are prone to MHT, necessitate medical assessment and close follow-up for hypertension.

Job strain and masked hypertension

OBJECTIVES

To determine whether psychosocial work characteristics are associated with the prevalence of masked hypertension in a population of white collar workers.

METHODS

White-collar workers were recruited from three public organizations. Blood pressure (BP) was measured at the workplace for manual measurements (mean of the first three readings taken by a trained assistant) followed by ambulatory measurements (mean of all subsequent readings taken during the working day). Masked hypertension (MH) was defined as manual BP <140/90 mm Hg, and ambulatory BP ≥135/85 mm Hg. Job strain was evaluated, using the quadrant method for exposure assessment, as well as alternative formulations.

RESULTS

BP measurements were obtained from 2,357 workers (80% participation, 61% women; mean age, 44 years). For men, being in the active group (high psychological demands and high decision latitude) was associated with MH (adjusted odds ratio, 2.07; 95% confidence interval, 1.30-3.31). No significant association with a higher prevalence of MH was observed in women.

CONCLUSION

MH is associated with job strain in men. Workers in "active" job situations may be more likely to have the condition.

Daily interpersonal conflict predicts masked hypertension in an urban sample

BACKGROUND

Masked hypertension (MH) is a risk factor for cardiovascular and cerebrovascular diseases. However, little is known about the effect of psychosocial stressors on MH.

METHODS

Daily interpersonal conflict was examined as a predictor of elevated ambulatory blood pressure (ABP) in a community sample of 240 unmedicated black and Latino(a) adults (63% women; mean age 36 years) who had optimal office blood pressure (BP) readings (≤120/80 mm Hg). Electronic diaries were used to assess daily interpersonal conflict (i.e., perceptions of being treated unfairly/harassed during social interactions). Participants rated the degree to which they experienced each interaction as unfair or harassing on a scale of 1-100. Systolic and diastolic ABP (SysABP and DiaABP, respectively) were collected using a validated 24-h ABP monitor. Participants were classified as having marked MH (MMH) if the average of all readings obtained yielded SysABP: ≥135 mm Hg or DiaABP: ≥85 mm Hg. Logistic regression was used to examine whether daily interpersonal conflict is an independent predictor of MMH.

RESULTS

This form of MMH (i.e., optimal office BP plus elevated ABP) was present in 21% of participants (n = 50). Those with MMH (vs. without) were significantly more likely to be men (P < 0.001). Daily harassment and unfair treatment scores were significant predictors of MMH group status (P < 0.05). Participants with harassment scores >30 were significantly more likely to be in the MMH group.

CONCLUSION

MH may be a concern, even for patients with optimal office BP. Evaluating exposure to psychosocial stressors, including routine levels of interpersonal conflict may help to identify those patients who might benefit from further clinical follow-up.

Masked hypertension: evaluation, prognosis, and treatment

Blood pressure (BP) may be high during usual daily life in one out of 7-8 individuals with normal BP in the clinic or doctor's office. This condition is usually defined as masked hypertension (MH). Prevalence of MH varied across different studies depending on patient characteristics, populations studied, and different definitions of MH. Self-measured BP and ambulatory BP (ABP) have been widely used to identify subjects with MH. Various factors have been identified as possible determinants of MH. Cigarette smoking, alcohol, physical activity, job, and psychological stress may increase BP out of the clinical environment in otherwise normotensive individuals, leading to MH. In most studies, target organ damage was comparable in subjects with MH and those with sustained hypertension, and greater than in those with true normotension. Subjects with MH showed a 1.5- to 3-fold higher risk of major cardiovascular (CV) disease than those with normotension, and their risk was not different from that of patients with sustained hypertension. In an overview of literature, we found that the risk of major CV disease was higher in subjects with MH than in the normotensive subjects regardless of the definition of MH based on self-measured BP (hazard ratio (HR) 2.13; 95% confidence interval (CI): 1.35-3.35; P = 0.001) or 24-h ABP (HR 2.00; 95% CI: 1.54-2.60; P < 0.001). MH is an insidious and prognostically adverse condition that can be reliably diagnosed by self-measured BP and ABP. MH should be searched for in subjects who appear to be more likely to have this condition. Antihypertensive treatment is envisaged in these subjects, although the associated outcome benefits are still undetermined.

Masked hypertension: different blood pressure measurement methodology and risk factors in a working population

OBJECTIVES

To estimate the prevalence of masked hypertension when the same ambulatory device is used for both manual and ambulatory blood pressure measurements and to measure associations with lifestyle risk factors in a working population.

METHODS

White-collar workers were recruited from three public organizations. Blood pressure was measured at the workplace using Spacelabs 90207 for manual measurements (mean of the first three readings taken by a trained assistant) followed by ambulatory measurements (mean of every other reading obtained during the working day). Masked hypertension was defined as manual blood pressure measurement of less than 140/90 mmHg and ambulatory blood pressure measurement of at least 135/85 mmHg. Smoking, alcohol intake, BMI and leisure physical activity were also assessed.

RESULTS

Blood pressure measurements were obtained from 2370 workers (80% participation, 61% women; mean age = 44 years). Masked hypertension was diagnosed in 15.02% of the participants. The prevalence was higher in men [adjusted odds ratio (OR) = 2.38, 95% confidence interval (CI) = 1.86-3.05]. The prevalence in men increased with age (adjusted OR = 2.08 for 40-49 years, 95% CI = 1.33-3.26 and adjusted OR = 1.91 for > or =50 years, 95% CI = 1.20-3.04) and BMI (adjusted OR = 1.78 for BMI > or = 27, 95% CI = 1.21-2.64). The prevalence in women increased with BMI (adjusted OR = 1.65 for BMI > or =27, 95% CI = 1.14-2.39) and alcohol intake (adjusted OR = 2.12 for at least six drinks per week, 95% CI = 1.34-3.35).

CONCLUSION

Masked hypertension is frequent and still present when blood pressure is measured out of the office, using the same device for manual and ambulatory measurements. Sex, age, BMI and alcohol intake are associated with masked hypertension.

Prevalence, causes, and consequences of masked hypertension: a meta-analysis

BACKGROUND

Masked hypertension (MH) is a relatively newly detected condition of which little is known. More information about MH may help to improve overall antihypertensive health care. We aimed to investigate the prevalence, potential causes, and associated consequences of MH.

METHODS

We searched published literature using MEDLINE, EMBASE, and the Cochrane database completed with references cited in reviews and original study articles. We restricted our research to articles written in the English, German, French, and Spanish language. Studies were included only when the prevalence of MH was reported, office blood pressure (BP) values were given, and methods of BP measurements were described in detail. All data were extracted independently by two readers with a standardized protocol and data-collection form.

RESULTS

The prevalence of MH averaged 16.8% (95% confidence interval 13.0-20.5%). The MH prevalence was 7% for children and 19% for adults. MH prevalences did not differ significantly when determined with self or ambulatory BP measurement (21.1% vs. 16.8%; P = 0.42). Subjects with MH had significantly higher left ventricular mass index (LVMI) values than normotensives (110 vs. 98 g/m2; P < 0.01) but similar values as sustained hypertensives (109 g/m2). In addition, patients with MH were more often smokers than normotensives (mean difference 18%; P < 0.03).

CONCLUSIONS

MH strikes about a quarter of the patients who were initially classified as normotensives (based on office BP measurements) and of treated hypertensives. Patients with MH seem to have a similar cardiovascular risk as sustained hypertensives but they may remain undetected. The presence of MH seems to be a matter of a coincidently low office BP value not related to certain subject characteristics although the chance of its presence may be increased by smoking and antihypertensive treatment.