Limitations of the difference between clinic and daytime blood pressure as a surrogate measure of the ‘white-coat’ effect

Background: We recently demonstrated how orthostatic hypotension might be used to identify out-of-office blood pressure phenotypes, including white coat effects and nocturnal non-dipping patterns. However, these findings have not been replicated in a population with chronic kidney disease (CKD). Objective: To examine the association between orthostatic hypotension (OH) or hypertension (OHTN) with ambulatory BP in adults with CKD. Methods: CRIC is a prospective multicenter observation cohort study of participants with CKD. Standing BP at 1 minute and ABPM were obtained on 1467 participants. OH was defined as a 20mmHg drop in systolic BP (SBP) or 10 mmHg drop in diastolic BP (DBP) when changing from seated to standing positions. OHTN was defined as a 20 mmHg or 10mmHg rise in SBP or DBP respectively when changing from seated to standing position. White coat effects, based on ABPM, was defined as the difference between seated clinic and ambulatory BP. Systolic and diastolic night to day ratio was also calculated. Results: Of the 1467 participants (age: 58 ± 10 yrs, 44% female, 39% black) 73 had OH and 165 had OHTN). OH was positively associated with systolic and diastolic white coat effect (β=5.9 [0.9, 10.9] and 4.2 [1.3, 7.1]). OHTN was negatively associated with diastolic white coat effect (-4.9 [-6.9, -3]). OH was positively associated with systolic and diastolic night-to-day ratio (0.03 [0.01, 0.05] and 0.03 [0.01, 0.06] respectively). Conclusions: Clinic-based assessments of OH and OHTN may be useful for identifying BP phenotypes often missed with seated office BP measurements in CKD patients.

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The white-coat effect is associated with increased blood pressure reactivity to physical activity

Blood Pressure Monitoring ◽

10.1097/00126097-200208000-00002 ◽

2002 ◽

Vol 7 (4) ◽

pp. 209-213 ◽

Cited By ~ 10

Author(s):

Andrew C. Leary ◽

Peter T. Donnan ◽

Thomas M. MacDonald ◽

Michael B. Murphy

Keyword(s):

Physical Activity ◽

Blood Pressure ◽

White Coat ◽

Blood Pressure Reactivity ◽

White Coat Effect ◽

Pressure Reactivity

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Examining the effectiveness of telemonitoring with routinely acquired blood pressure data in primary care: challenges in the statistical analysis

BMC Medical Research Methodology ◽

10.1186/s12874-021-01219-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Richard A. Parker ◽

Paul Padfield ◽

Janet Hanley ◽

Hilary Pinnock ◽

John Kennedy ◽

...

Keyword(s):

Blood Pressure ◽

Primary Care ◽

Statistical Analysis ◽

Propensity Score ◽

Random Coefficient ◽

White Coat ◽

White Coat Effect ◽

Regression Adjustment ◽

The Impact

Abstract Background Scale-up BP was a quasi-experimental implementation study, following a successful randomised controlled trial of the roll-out of telemonitoring in primary care across Lothian, Scotland. Our primary objective was to assess the effect of telemonitoring on blood pressure (BP) control using routinely collected data. Telemonitored systolic and diastolic BP were compared with surgery BP measurements from patients not using telemonitoring (comparator patients). The statistical analysis and interpretation of findings was challenging due to the broad range of biases potentially influencing the results, including differences in the frequency of readings, ‘white coat effect’, end digit preference, and missing data. Methods Four different statistical methods were employed in order to minimise the impact of these biases on the comparison between telemonitoring and comparator groups. These methods were “standardisation with stratification”, “standardisation with matching”, “regression adjustment for propensity score” and “random coefficient modelling”. The first three methods standardised the groups so that all participants provided exactly two measurements at baseline and 6–12 months follow-up prior to analysis. The fourth analysis used linear mixed modelling based on all available data. Results The standardisation with stratification analysis showed a significantly lower systolic BP in telemonitoring patients at 6–12 months follow-up (-4.06, 95% CI -6.30 to -1.82, p < 0.001) for patients with systolic BP below 135 at baseline. For the standardisation with matching and regression adjustment for propensity score analyses, systolic BP was significantly lower overall (− 5.96, 95% CI -8.36 to − 3.55 , p < 0.001) and (− 3.73, 95% CI− 5.34 to − 2.13, p < 0.001) respectively, even after assuming that − 5 of the difference was due to ‘white coat effect’. For the random coefficient modelling, the improvement in systolic BP was estimated to be -3.37 (95% CI -5.41 to -1.33 , p < 0.001) after 1 year. Conclusions The four analyses provide additional evidence for the effectiveness of telemonitoring in controlling BP in routine primary care. The random coefficient analysis is particularly recommended due to its ability to utilise all available data. However, adjusting for the complex array of biases was difficult. Researchers should appreciate the potential for bias in implementation studies and seek to acquire a detailed understanding of the study context in order to design appropriate analytical approaches.

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Abstract P634: The Influence Of Virtual Learning Environment On Therapy Adherence And On The White Coat Effect

Hypertension ◽

10.1161/hyp.66.suppl_1.p634 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Isabela R Fistarol ◽

Chao L Wen ◽

Luiz Bortolotto ◽

Margarida Vieira ◽

Miriam Tsunemi ◽

...

Keyword(s):

Quality Of Life ◽

Blood Pressure ◽

Educational Technology ◽

Learning Environment ◽

Statistical Difference ◽

Virtual Learning Environment ◽

White Coat ◽

Study Group ◽

White Coat Effect

Systemic arterial hypertension is a risk factor for cardiovascular diseases and has become a common public health problem. Health education associated with educational technology may be used to encourage patients’ adherence to treatment and enable them to adequately understand how harmful hypertension can be to health, thereby promoting their quality of life. OBJECTIVE: To evaluate the influence of a strategy in an individual orientation program using educational technology associated with virtual learning environment (VLE) of hypertension care on the reduction in the white coat effect and the improvement in blood pressure control to be promoted by a nurse in a hypertension unit in a government state hospital in São Paulo. METHODS AND MATERIALS:This was a randomized clinical education study conducted with two groups, the VLE group (study group, 10 patients) and the control group (16 patients). Both groups were interviewed 6 times by nurses during the 120-day follow-up at 20-day intervals. At baseline (randomization) and at the end of the study, the patients took Spielberg’s State-Trait Anxiety Inventory (STAI), the Morisky test, and the WHOQOL, a quality of life instrument, and had their blood pressure taken (ambulatory blood pressure monitoring [ABPM]). Both groups had their blood pressure, weight, and abdominal circumference measured. Only the study group had remote access to the VLE. This consisted of 6 specific educational modules, each released according to the encounter number. RESULTS: At baseline, there were no statistical differences between the two groups with respect to the sociodemographic and hemodynamic variables. At the end of the study, there was a significant statistical difference between the groups on the Morisky test (p=0.001) and on the WHOQOL with respect to domain 3 social (p=0.001). There was no statistical difference with respect to the white coat effect between the groups. Nor was there any statistical difference between the groups with respect to the association of the anxiety degree measured by STAI and the white coat effect.CONCLUSION: In light of the results, our strategy improved the quality of life in the social domain and changed the adherence behavior of the study group in relation to the forgetfulness of medication schedules.

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Abstract P114: White Coat Effect is Common Among Stroke Survivors

Hypertension ◽

10.1161/hyp.70.suppl_1.p114 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Adriana Morell ◽

Munachi Okpala ◽

Sean Savitz ◽

Anjail Z Sharrief

Keyword(s):

Blood Pressure ◽

Recurrent Stroke ◽

White Coat ◽

Uncontrolled Hypertension ◽

Stroke Survivors ◽

White Coat Effect ◽

Chi Squared ◽

Stroke Type ◽

Ischemic Attack ◽

Univariate Analyses

Background and Purpose: Among stroke survivors, uncontrolled hypertension is a major risk factor for recurrent stroke. Blood pressure (BP) medication titration often relies on office BP measures, which may be inaccurate due to the white coat effect (WCE). We sought to determine the prevalence of the WCE in stroke survivors and to determine whether clinical and demographic factors were associated with WCE. Methods: We followed ischemic and hemorrhagic stroke and transient ischemic attack patients with prior hypertension presenting to our stroke clinic for a BP study. Sitting BP was obtained by a medical assistant using an office automated BP machine (OABP). Patients also underwent BP measurement using BPtru, an automated machine that measures and averages five BPs with the patient alone in a room. BPtru approximate BPs obtained by the gold standard ambulatory blood pressure machine. Systolic BP (SBP) obtained by BPtru was subtracted from that obtained by OABP. WCE was defined as SBP difference ≥ 10mmHg. Uncontrolled BP was defined as SBP ≥ 135 mmHg by BPtru or ≥ 140 mmHg by OABP. We used student t-tests (continuous) and chi-squared or Fischer’s exact tests (categorical) for univariate analyses. Results: Of 94 patients, mean age was 60 (SD 12), 60.6% were male, 26.6% were Non-Hispanic White, 46.8% were Black, and 23.4% were Hispanic. Systolic OABP was 13.2 mmHg (SD 19.3) higher than BPtru SBP (student t-test; p <0.001). WCE was present in 58.5 % of participants and BP was misclassified as uncontrolled in 21.2%. In univariate analyses, age (p = 0.14), sex (p = 0.78), race (0.07), stroke type (0.92), body mass index (p = 0.65), and tobacco use (p = 0.35) were not significantly associated with presence of WCE. The presence of normal SBP by OABP was associated with a decreased likelihood of WCE (p = 0.006). Conclusions: Among hypertensive stroke patients following in a clinic, WCE was highly prevalent and one-fifth of patients were misclassified as uncontrolled. Neither race nor other previously described predictors of WCE were associated with WCE in this study. Our findings suggest that in patients with elevated office BP, findings should be confirmed with an automated machine like BPtru in order to avoid over-titration of medication or incorrect assessment of BP control.

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Abstract 11530: Age-Specific Differences Between Conventional and Ambulatory Daytime Blood Pressure Values

Circulation ◽

10.1161/circ.130.suppl_2.11530 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

David Conen ◽

Stefanie Aeschbacher ◽

Lutgarde Thijs ◽

Yan Li ◽

José Boggia ◽

...

Keyword(s):

Blood Pressure ◽

Population Based ◽

White Coat ◽

White Coat Hypertension ◽

Masked Hypertension ◽

Daytime Blood Pressure ◽

Collaborative Analysis ◽

The Individual ◽

Age Range ◽

Diagnosis Of Hypertension

Introduction: Mean daytime ambulatory blood pressure (ABP) values are considered to be lower than conventional BP (CBP) values, but data on this relation among younger individuals <50 years are scarce. To address this issue, we performed a collaborative analysis in a large group of participants representing a wide age range. Methods: CBP and 24-hour ABP were measured in 9550 individuals not taking BP lowering treatment from 13 population based cohorts. We compared the individual differences between daytime ABP and CBP according to 10-year age categories. Age-specific prevalences of white-coat hypertension and masked hypertension were calculated based on guideline-recommended thresholds. Results: Among individuals aged 18-30, 30-40 and 40-50 years, mean daytime systolic and diastolic ABP were significantly higher than the corresponding CBP (6.0, 5.2 and 4.7 mmHg for systolic BP; 2.5, 2.7 and 1.7 mmHg for diastolic BP, all p<0.0001) (Figure). Systolic and diastolic BP indices were similar in participants aged 50-60 years (p=0.20 and 0.11, respectively). In individuals aged 60-70 and ≥70 years, CBP was significantly higher than daytime ABP (5.0 and 13.0 mmHg for systolic BP; 2.0 and 4.2 mmHg for diastolic BP, all p<0.0001) (Figure). Accordingly, the prevalence of white coat hypertension exponentially increased from 2.2% to 19.5% from those aged 18-30 years to those aged ≥70 years, with some variation between men and women (prevalence 8.0% versus 6.1%, p=0.0003). Masked hypertension was more prevalent among men (21.1% versus 11.4%, p<0.0001). The age-specific prevalence of masked hypertension was 18.2%, 27.3%, 27.8%, 20.1% 13.6% and 10.2% in men, and 9.0%, 9.9%, 12.2%, 11.9%, 14.7% and 12.1% in women. Conclusions: In this large collaborative analysis we found that the relation between daytime ABP and CBP strongly varies by age. These findings may have important implications for the diagnosis of hypertension and its subtypes in clinical practice.

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Abstract P198: Clinic versus Out-of-Clinic Daytime Blood Pressure Among Older Adults: Data From the Jackson Heart Study

Circulation ◽

10.1161/circ.131.suppl_1.p198 ◽

2015 ◽

Vol 131 (suppl_1) ◽

Author(s):

Rikki M Tanner ◽

Daichi Shimbo ◽

Samantha Seals ◽

Gbenga Ogedegbe ◽

Paul Muntner

Keyword(s):

Blood Pressure ◽

Older Adults ◽

Blood Pressure Monitoring ◽

White Coat ◽

Older Individuals ◽

Jackson Heart Study ◽

Large White ◽

Younger Adults ◽

White Coat Effect ◽

Heart Study

In the US, antihypertensive medication treatment decisions are primarily based on blood pressure (BP) measurements obtained in the clinic setting. The optimal systolic BP (SBP) goal for adults ≥60 years is controversial and a large difference between clinic and out-of-clinic daytime BP, a white-coat effect, may be present in older individuals. We estimated the white-coat effect and calculated the percentage of untreated and treated adults <60 and ≥60 years with elevated clinic BP (defined as SBP/diastolic BP [DBP] ≥140/90 mmHg), but non-elevated out-of-clinic daytime BP (“daytime BP”, defined as SBP/DBP <135/85 mmHg) among 257 African-American participants in the Jackson Heart Study with at least 10 daytime ambulatory BP measurements. For the overall population, the white-coat effect for SBP was 12.2 mmHg (95% confidence interval [CI]: 9.2-15.1) in older adults and 8.4 mmHg (95% CI: 5.7-11.1) in younger adults (p=0.06). After multivariable (MV) adjustment, this difference was 1.3 mmHg. Among those without diabetes or chronic kidney disease (CKD), the white coat effect for SBP was 15.2 mmHg (95% CI: 10.1-20.2) and 8.6 mmHg (95% CI: 5.0-12.3) for older and younger adults, respectively (p=0.04). After MV adjustment, this difference was 5.9 mmHg. Also, SBP ≥150 mmHg versus <150 mm Hg was associated with a larger white-coat effect in the overall population after MV adjustment. Among those without CKD or diabetes, older age and SBP ≥150 mmHg were associated with a larger white-coat effect after MV adjustment. Among younger and older participants with elevated clinic BP, the prevalence of non-elevated daytime BP was 34% (95% CI: 26%-44%) and 32% (95% CI: 24%-40%), respectively (p=0.64), in the overall population and 35% (95% CI: 24%-48%) and 43% (95% CI: 31%-56%), respectively, for those without CKD or diabetes (p=0.37). In conclusion, a large white-coat effect was present among older adults. These data suggest a role for ambulatory blood pressure monitoring in preventing potential over-treatment for hypertension among older adults.

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