Association between white-coat effect and blunted dipping of nocturnal blood pressure

Relationship of the White Coat Effect with Endpoints and Several Prognostic Indicators in Hypertensive Patients Treated with Regular Antihypertensive Therapy

Aim of the study was to evaluate in a prospective cohort study the relationship between the severity of the white coat effect (WHE) in patients with hypertension, who treated with regular antihypertensive therapy, and the composite endpoint, several prognostic indicators, in a routine clinical practice.

Material and Methods. We analyzed the data of a prospective cohort study, which included 125 patients with hypertension who received regular antihypertensive therapy. The study consisted of three visits (baseline, 6 and 12 months) and an outcome data collection period (30.1±7.6 months of follow-up after the third visit). This study included three visits every 3 months: 1 visit – screening, ambulatory blood pressure monitoring (ABPM) session, Echo; 2 – assessment of the patient’s status and the therapy effectiveness; 3- assessment of the patient’s status, ABPM session, Echo (the total number of ABPM was 239, Echo - 240). The primary composite endpoint included death for any reason angina pectoris, transient ischemic attack, development of chronic heart failure, arterial revascularization, frequent ventricular extrasystoles, atrial fibrillation, secondary - deterioration of the cardiovascular diseases course and tertiary endpoint – deterioration of the arterial hypertension, concomitant diseases course.

Results. The study involved 125 patients: 28 men (22%), 97 women (78%), mean age was 62.6±0.8 years, duration of hypertension 11.6±0.8 years, height 163.6±0.7 cm, body weight 83.1±1.4 kg. The baseline mean daytime systolic BP (SBP) was 125.1±9.8 and diastolic (DBP) – 76.1±7.0 mm Hg, age was 62.8±9.0 years, the WCE level for SBP was 16.5±1.4, for DBP 10.9±0.7 mm Hg. We identified a positive correlation between tertiary composite endpoint data and WCE: for systolic WCE (SWCE) (F = 4.7, p<0.031). We found correlations between WCE and Echo parameters: 1) SWCE level had with LVMI (r = 0.16. p<0.017); 2) diastolic WCE (DWCE) had negative relationship with LV contractility parameters.

Conclusions. Thus, only systolic WCE level had correlation with composite endpoint data and LVMI. DWCE level had negative associations with echocardiography LV contractility parameters.

Nighttime mean arterial pressure is associated with left ventricular hypertrophy in white‐coat hypertension

White‐coat hypertension (WCH) is associated with increased cardiovascular risks. To investigate the relationship between WCH and left ventricular hypertrophy (LVH), the authors recruited 706 participants who underwent anthropometric measurements, blood laboratory analysis, 24h ambulatory blood pressure monitoring (ABPM), and echocardiography. The authors defined WCH as elevated office BP but normal ABPM over 24h, daytime, and nighttime periods. The authors compared the proportion of LVH between the true normotension (NT) and the WCH population, and further assessed the associations between BP indexes and LVH in the two groups, respectively. The proportion of LVH was significantly higher in the WCH group than in NT participants (19.70% vs. 13.12%, P = .036). In the NT group, 24h SBP, 24h PP, daytime SBP, daytime PP and SD of nighttime SBP were associated with LVH after adjustment for demographic and blood biochemical data (all P < .05). In the WCH population, LVH was associated with 24h SBP, nighttime SBP, nighttime MAP, and office SBP after adjustment (all P < .05). However, on forward logistic regression analysis with all the BP indexes listed above, only 24h SBP (OR = 1.057, 1.017–1.098, P < .001) in the NT group, and nighttime MAP (OR = 1.114, 1.005–1.235, P < .05) and office SBP (OR = 1.067, 1.019–1.117, P < .001) in the WCH group were still significantly associated with LVH. Our study suggests that the proportion of LVH is higher in WCH patients than in the NT population. Furthermore, elevated nighttime MAP and office SBP may play critical roles in the development of LVH in the WCH population.

High prevalence of non-dipping patterns among Black Africans with uncontrolled hypertension: a secondary analysis of the CREOLE trial

BACKGROUND

Dipping of blood pressure (BP) at night is a normal physiological phenomenon. However, a non-dipping pattern is associated with hypertension mediated organ damage, secondary forms of hypertension and poorer long-term outcome. Identifying a non-dipping pattern may be useful in assessing risk, aiding the decision to investigate for secondary causes, initiating treatment, assisting decisions on choice and timing of antihypertensive therapy, and intensifying salt restriction.

OBJECTIVES

To estimate the prevalence and factors associated with non-dipping pattern and determine the effect of 6 months of three antihypertensive regimens on the dipping pattern among Black African hypertensive patients.

METHODS

This was a secondary analysis of the CREOLE Study which was a randomized, single blind, three-group trial conducted in 10 sites in 6 Sub-Saharan African countries. The participants were 721 Black African patients, aged between 30 and 79 years, with uncontrolled hypertension and a baseline 24-h ambulatory blood pressure monitoring (ABPM). Dipping was calculated from the average day and average night systolic blood pressure measures.

RESULTS

The prevalence of non-dipping pattern was 78% (564 of 721). Factors that were independently associated with non-dipping were: serum sodium > 140 mmol/l (OR = 1.72, 95% CI 1.17-2.51, p-value 0.005), a higher office systolic BP (OR = 1.03, 95% CI 1.01-1.05, p-value 0.003) and a lower office diastolic BP (OR = 0.97, 95% CI 0.95-0.99, p-value 0.03). Treatment allocation did not change dipping status at 6 months (McNemar's Chi2 0.71, p-value 0.40).

CONCLUSION

There was a high prevalence of non-dipping among Black Africans with uncontrolled hypertension. ABPM should be considered more routinely in Black Africans with uncontrolled hypertension, if resources permit, to help personalise therapy. Further research is needed to understand the mechanisms and causes of non-dipping pattern and if targeting night-time BP improves clinical outcomes. Trial registration ClinicalTrials.gov (NCT02742467).

Nocturnal blood pressure: the dark side of white-coat hypertension

AIM

The impact of defining white-coat hypertension (WCH) and white-coat uncontrolled hypertension (WCUH) based on daytime and night-time thresholds of ambulatory blood pressure (ABP), instead of 24-h mean value, is unclear. We aimed to reclassify BP status according to both diurnal and nocturnal thresholds in a large sample of hypertensive patients seen in a specialist center and previously classified as WCH and WCUH based on 24-h BP values.

METHODS

A data-base of 7353 individual 24-h ABP monitoring (ABPM) from untreated and treated hypertensive individuals with office BP at least 140 mmHg and/or 90 mmHg was analysed and a subset of 3223 patients characterized by mean 24-h BP less than 130/80 mmHg (i.e. WCH and WCUH) was included in the present analysis.

RESULTS

As many as 1281 patients were classified as WCH and 1942 as WCUH. Among them, elevated out-of-office BP according to night-time threshold (i.e. ≥120/70 mmHg) was found in about 30% of cases. In particular, prevalence rates of nocturnal hypertension were 26.9% in WCH and 31.8% in WCUH. Isolated daytime hypertension (i.e. ≥135/85 mmHg) was detected in an additional 4% of individuals.

CONCLUSION

Classification of WCH and WCUH based on mean 24-h BP thresholds does not allow to detect an adverse BP phenotype, such as nocturnal hypertension in a large fraction of untreated and treated patients.

White coat syndrome and its variations: differences and clinical impact

Hypertension is closely linked to increased cardiovascular risk and development of target organ damage (TOD). Therefore, proper clinical follow-up and treatment of hypertensive subjects are mandatory. A great number of individuals present a variation on blood pressure (BP) levels when they are assessed either in the office or in the out-of-office settings. This phenomenon is defined as white coat syndrome - a change in BP levels due to the presence of a physician or other health professional. In this context, the term "white coat syndrome" may refer to three important and different clinical conditions: 1) white coat hypertension, 2) white coat effect, and 3) masked hypertension. The development of TOD and the increased cardiovascular risk play different roles in these specific subgroups of white coat syndrome. Correct diagnose and clinical guidance are essential to improve the prognosis of these patients. The aim of this review was to elucidate contemporary aspects of these types of white coat syndrome on general and hypertensive population.

Prevalence of white coat and masked hypertension in Africa: A systematic review and meta-analysis

Data on masked hypertension (MH) and white-coat hypertension (WCH) in African populations are needed to estimate the true prevalence of hypertension in these populations because they have the highest burden of the disease. We conducted the first systematic review and meta-analysis that summarized available data on the prevalence of WCH and MH in Africa. We searched PubMed and Scopus to identify all the articles published on MH and WCH in populations living in Africa from inception to November 30, 2017. We reviewed each study for methodological quality. A random-effects model was used to estimate the prevalence of WCH and MH across studies. Eleven studies were included, all having a low-risk of bias. The prevalence of masked hypertension was 11% (95% CI: 4.7-19.3; 10 studies) in a pooled sample of 7789 individuals. The prevalence of WCH was 14.8% (95% CI: 9.4-21.1; 8 studies) in a pooled sample of 4451 individuals. There was no difference on the prevalence of WCH and MH between studies in which participants were recruited from the community and the hospital. The prevalence of MH was higher in urban areas compared to rural ones; there was no difference for WCH. WHC and MH seem to be frequent in African populations, suggesting the importance of out-of-clinic BP measurement in the diagnosis and management of patients with hypertension in Africa, especially in urban areas for MH.

Epidemiology of masked and white-coat hypertension: the family-based SKIPOGH study

Objective

We investigated factors associated with masked and white-coat hypertension in a Swiss population-based sample.

Methods

The Swiss Kidney Project on Genes in Hypertension is a family-based cross-sectional study. Office and 24-hour ambulatory blood pressure were measured using validated devices. Masked hypertension was defined as office blood pressure<140/90 mmHg and daytime ambulatory blood pressure≥135/85 mmHg. White-coat hypertension was defined as office blood pressure≥140/90 mmHg and daytime ambulatory blood pressure<135/85 mmHg. Mixed-effect logistic regression was used to examine the relationship of masked and white-coat hypertension with associated factors, while taking familial correlations into account. High-normal office blood pressure was defined as systolic/diastolic blood pressure within the 130–139/85–89 mmHg range.

Results

Among the 652 participants included in this analysis, 51% were female. Mean age (±SD) was 48 (±18) years. The proportion of participants with masked and white coat hypertension was respectively 15.8% and 2.6%. Masked hypertension was associated with age (odds ratio (OR) = 1.02, p = 0.012), high-normal office blood pressure (OR = 6.68, p<0.001), and obesity (OR = 3.63, p = 0.001). White-coat hypertension was significantly associated with age (OR = 1.07, p<0.001) but not with education, family history of hypertension, or physical activity.

Conclusions

Our findings suggest that physicians should consider ambulatory blood pressure monitoring for older individuals with high-normal office blood pressure and/or who are obese.

Relations between white coat effects and left ventricular mass index or arterial stiffness: role of nocturnal blood pressure dipping

BACKGROUND

Whether independent relationships between white coat effects (office minus day (office-day blood pressure (BP))) and organ damage or arterial stiffness may be explained by associations with an attenuated nocturnal BP dipping, has not been determined.

METHODS

In 750 participants from a sample of African ancestry, office and 24-hour BP, carotid-femoral pulse wave velocity (PWV) (applanation tonometry and SphygmoCor software) (n = 662), and left ventricular mass indexed to height(2.7) (LVMI) (echocardiography) (n = 463) were determined.

RESULTS

Office-day systolic BP (SBP) was correlated with day minus night (day-night) SBP, percentage night divided by day (night/day) SBP, and night SBP (P < 0.0005), and these relationships persisted with adjustments for confounders, including day SBP (P < 0.005). With adjustments for 24-hour SBP and additional confounders, office-day SBP was associated with LVMI (P < 0.01) and PWV (P < 0.0001). With adjustments for day SBP and additional confounders, day-night SBP, percentage night/day SBP, and night SBP were related to PWV (P < 0.05) but not to LVMI (P > 0.44). The relationships between office-day SBP and LVMI or PWV persisted with adjustments for either day-night or percentage night/day SBP (LVMI: P = 0.01; PWV: P < 0.0001) or night SBP (LVMI: P < 0.01; PWV: P = 0.0001), and in product of coefficient mediation analysis with appropriate adjustments, neither indexes of nocturnal BP dipping nor nocturnal BP per se contributed toward the impact of office-day BP on LVMI or PWV (P > 0.09).

CONCLUSIONS

In a group of African ancestry, although white coat effects are independently associated with an attenuated nocturnal decrease in SBP, neither decreased BP dipping nor nocturnal BP contribute toward the independent relationships between white coat effects and LVMI or arterial stiffness.

Marked underestimation of blood pressure control with conventional vs. ambulatory measurements in an urban, developing community of African ancestry

BACKGROUND

As groups of African descent may have higher nocturnal blood pressure (BP) for a given day BP than other ethnic groups, we ascertained whether this translates into differences in conventional (CBP) and 24-h ambulatory (ABP) BP control at a community level.

METHODS

Ambulatory 24-h, day and night BP (model 90207; SpaceLabs, Issaquah, WA) and CBP (mean of five values) control rates were determined in 689 randomly selected participants (>16 years) of African ancestry in South Africa. Target organ effects were determined from urinary microalbumin-to-creatinine ratios (ACR) and aortic pulse wave velocity (PWV, applanation tonometry).

RESULTS

Of the participants 45.7% were hypertensive and 22.6% were receiving antihypertensive medication. More participants had uncontrolled BP at night (34.0%) than during the day (22.6%, P < 0.0001). Uncontrolled CBP was noted in 37.2% of participants, while a much lower proportion had uncontrolled ABP (24.1%) (P < 0.0001). Marked differences in the proportion of hypertensive participants with uncontrolled CBP and ABP were noted (treated: CBP = 62.2%, ABP = 33.3%, P < 0.0001; all: CBP = 81.3%, ABP = 44.4%, P < 0.0001). These differences were accounted for by a high prevalence of isolated increases in CBP (white-coat effects) (treated = 35.9%; all = 39.4%). Indeed, after censoring data from participants with white-coat effects, similar CBP and ABP control rates were noted. Participants with white-coat effects had similar ACR and PWV values as participants with normal ABP and CBP.

CONCLUSIONS

In communities of African descent, despite worse BP control at night than during the day, a high prevalence of white-coat effects translates into a striking underestimation of BP control in hypertensives when employing CBP rather than ABP measurements.

Genome-wide association study of blood pressure extremes identifies variant near UMOD associated with hypertension

Hypertension is a heritable and major contributor to the global burden of disease. The sum of rare and common genetic variants robustly identified so far explain only 1%–2% of the population variation in BP and hypertension. This suggests the existence of more undiscovered common variants. We conducted a genome-wide association study in 1,621 hypertensive cases and 1,699 controls and follow-up validation analyses in 19,845 cases and 16,541 controls using an extreme case-control design. We identified a locus on chromosome 16 in the 5′ region of Uromodulin (UMOD; rs13333226, combined P value of 3.6×10⁻¹¹). The minor G allele is associated with a lower risk of hypertension (OR [95%CI]: 0.87 [0.84–0.91]), reduced urinary uromodulin excretion, better renal function; and each copy of the G allele is associated with a 7.7% reduction in risk of CVD events after adjusting for age, sex, BMI, and smoking status (H.R. = 0.923, 95% CI 0.860–0.991; p = 0.027). In a subset of 13,446 individuals with estimated glomerular filtration rate (eGFR) measurements, we show that rs13333226 is independently associated with hypertension (unadjusted for eGFR: 0.89 [0.83–0.96], p = 0.004; after eGFR adjustment: 0.89 [0.83–0.96], p = 0.003). In clinical functional studies, we also consistently show the minor G allele is associated with lower urinary uromodulin excretion. The exclusive expression of uromodulin in the thick portion of the ascending limb of Henle suggests a putative role of this variant in hypertension through an effect on sodium homeostasis. The newly discovered UMOD locus for hypertension has the potential to give new insights into the role of uromodulin in BP regulation and to identify novel drugable targets for reducing cardiovascular risk.

Hypertension is the leading contributor to global mortality with a global prevalence of 26.4% in 2000, projected to increase to 29.2% by 2025. While 50%–60% of population variation in blood pressure can be attributable to additive genetic factors, all the genetic variants robustly identified so far explain only 1%–2% of the population variance indicating the presence of additional undiscovered risk variants. Using an extreme case-control strategy, we have discovered a SNP in the promoter region of the uromodulin gene (UMOD) to be associated with hypertension (minor allele protective against hypertension). We then validated this association using large-scale population and case-control studies, where similar extreme criteria for selection of cases and controls have been used (21,466 cases and 18,240 controls). As the locus was related to uromodulin, a protein exclusively expressed in the kidneys, we show that the association is independent of renal dysfunction. We also show preliminary evidence that the SNP allele which is protective against hypertension is also protective against cardiovascular events in 26,654 Swedish subjects followed-up for 12 years. The newly discovered UMOD locus for hypertension has the potential to give unique insights into the role of uromodulin in BP regulation and to identify novel drugable targets.

Early-onset depression, anxiety, and risk of subsequent coronary heart disease: 37-year follow-up of 49,321 young Swedish men

OBJECTIVES

The purpose of this study was to investigate the long-term cardiac effects of depression and anxiety assessed at a young age, when reverse causation is not feasible.

BACKGROUND

Most prospective studies found a relatively strong association between depression and subsequent coronary heart disease (CHD). However, almost exclusively, only middle-age or older participants were examined, and subclinical atherosclerosis might contribute to the observed association. The prospective association between anxiety and CHD was less evident in previous studies and has been subjected to similar methodological concerns on the possibility for a reverse causation.

METHODS

In a nationwide survey, 49,321 young Swedish men, 18 to 20 years of age, were medically examined for military service in 1969 and 1970. All the conscripts were seen by a psychologist for a structured interview. Conscripts reporting or presenting any psychiatric symptoms were seen by psychiatrists. Depression and anxiety was diagnosed according to International Classification of Diseases-8th Revision (ICD-8). Data on well-established CHD risk factors and potential confounders were also collected (i.e., anthropometrics, diabetes, blood pressure, smoking, alcohol consumption, physical activity, socioeconomic position, family history of CHD, and geographic area). Participants were followed for CHD and for acute myocardial infarction for 37 years.

RESULTS

Multiadjusted hazard ratios associated with depression were 1.04 (95% confidence interval [CI]: 0.70 to 1.54), 1.03 (95% CI: 0.65 to 1.65), for CHD and for acute myocardial infarction, respectively. The corresponding multiadjusted hazard ratios for anxiety were 2.17 (95% CI: 1.28 to 3.67) and 2.51 (95% CI: 1.38 to 4.55).

CONCLUSIONS

In men, aged 18 to 20 years, anxiety as diagnosed by experts according to ICD-8 criteria independently predicted subsequent CHD events. In contrast, we found no support for such an effect concerning early-onset depression in men.