Prevalence and predictors of white-coat response in patients with treated hypertension
======================================================================================

* Mary B. MacDonald
* Gail P.  Laing
* Merne P.  Wilson
* Thomas W.  Wilson

## Abstract

**Background:** White-coat response, defined as higher office blood pressure readings than ambulatory readings, is common. Few studies have estimated its prevalence among subjects with treated hypertension, and almost none have defined its determinants. The objective of this study was to estimate the prevalence of white-coat response among subjects with treated hypertension and to determine whether the phenomenon could be predicted using clinical and psychometric data.

**Methods:** A total of 103 treated patients (55 men and 48 women) with uncontrolled hypertension who attended a hypertension outpatient clinic in Saskatoon between September 1993 and December 1995 were entered into the study. Patients had at least 2 clinic blood pressure readings of 140/90 mm Hg or higher, had no target organ damage or left ventricular hypertrophy, and had been prescribed 2 or more classes of antihypertensive drugs. Patients had blood pressure measured in the supine position in the clinic, were placed on 24-hour ambulatory blood pressure monitoring and then completed questionnaires before returning to the clinic. Patients were classified as exhibiting a white-coat response if their mean daytime ambulatory systolic/diastolic blood pressure was 139/89 mm Hg (both) or less, or if the systolic/diastolic pressure was at least 20/15 mm Hg (both) lower than the clinic reading.

**Results:** Eleven men (20%, 95% confidence interval [CI] 10%-33%) and 26 women (54%, 95% CI 39%-69%) showed white-coat response. Logistic regression modelling showed that determinants such as stress had significantly different effects among men and women. Separate models were therefore created for men and women. For women, perceived level of stress was the most important predictor of white-coat response (odds ratio [OR] per unit 7.0, 95% CI 1.3-36.0), followed by time since diagnosis. For men, depression was a weak predictor, with higher depression scores predicting sustained hypertension (OR per unit 1.2, 95% CI 1.01-1.5).

**Interpretation:** Sex is an important factor in white-coat response. Attempts to predict white-coat response from psychometric variables should take sex differences into account. Clinical variables were not effective as predictors of white-coat response.

In some people blood pressure measured in the office is substantially higher than their average ambulatory blood pressure. [1] This "white-coat response" may persist on subsequent visits, which suggests that it is a conditioned response that is habitual and specific to the clinical situation. [2, 3] Depending on the upper limit set for mean daytime ambulatory blood pressure, the prevalence of white-coat response can range from 18% to 60% in populations with untreated hypertension. [4]

Several investigators have attempted to identify clinical, psychological and demographic predictors of white-coat response, but findings have been conflicting or nonsignificant. [3, 5–8] Female sex was a predictor of the response in one study. [7] Other variables examined to date have not been strong predictors.

Most studies of white-coat response have been conducted in subjects with normal blood pressure and those with borderline hypertension who were not receiving drug treatment. Recently, however, Myers and Reeves [9, 10] found that 70% to 73% of treated patients showed a white-coat response, and 31% to 32% exhibited a "marked white-coat effect." Thus, white-coat response remains a consideration even among patients with treated hypertension.

The purpose of our study was twofold: to determine the prevalence of white-coat response (i.e., difference between clinic and ambulatory blood pressure, or a normal ambulatory blood pressure) in a population of subjects with treated hypertension whose clinic blood pressure remained uncontrolled despite therapy; and to determine whether selected psychological factors or clinical variables are predictors of white-coat response.

## Methods

The University of Saskatchewan Advisory Committee on Ethics in Human Experimentation approved the study.

We considered consecutive patients with essential hypertension who attended the Hypertension Outpatient Clinic at the Royal University Hospital, Saskatoon, between September 1993 and December 1995 and whose clinic blood pressure remained uncontrolled despite being prescribed at least 2 different classes of antihypertensive medications. The same nurse recorded the clinic blood pressure with subjects in the supine position using Canadian Hypertension Society guidelines. [11] Study subjects had 2 or more clinic blood pressure readings of at least 140/90 mm Hg (either/or) 1 month apart but no greater than 200/120 mm Hg (either/or), were 18 years of age or more and had no target organ damage or left ventricular hypertrophy, as evidenced by echocardiography. The rate of compliance, estimated by pill counts, was 80% or more. Over 90% of eligible patients participated.

To detect a difference of 0.5 units in the score on the Perceived Stress Level questionnaire between subjects with a white-coat response and those with sustained hypertension, and assuming that the standard deviation of the data was 0.6 units (estimated from our previous study [12, 13]), we needed to enter 31 subjects in either group. We assumed that about one-third of the subjects would meet the criteria for white-coat response. Therefore, we planned to study 100 patients.

Ambulatory blood pressure monitoring was done on a typical weekday with the SpaceLabs 90207 system (SpaceLabs Medical Products, Ltd., Mississauga, Ont.). Patients were encouraged to pursue their usual activities. Ambulatory monitors were attached at the completion of the clinic visit, calibrated and removed after 24 hours. Blood pressure was recorded every 20 minutes from 8 am to 10 pm and every 60 minutes from 10 pm to 8 am. Recordings were judged adequate if there were at least 25 usable blood pressure readings over a minimum of 8 hours, excluding sleeping hours. All recordings met these criteria.

Subjects were identified as exhibiting white-coat response if their mean daytime ambulatory systolic/diastolic blood pressure was 139/89 mm Hg (both) or lower, or if the systolic/diastolic pressure was at least 20/15 mm Hg (both) lower than the clinic reading. All other subjects were considered to have sustained hypertension.

After beginning ambulatory monitoring, patients completed several questionnaires based on studies that explored the relation between white-coat response and factors such as stress, emotional reactivity, hostility and anger. The following psychometric tests were completed by the patients at their own pace: the Center for Epidemiologic Studies Depression (CES-D) Scale, [14] a 20-item self-report scale designed to measure symptoms of depression in the general population; the Cook-Medley Hostility Scale, [15] a 50-item true-false questionnaire that assesses the propensity to experience anger and hostility; the State-Trait Anxiety Inventory, [16] a 40-item questionnaire that measures anxiety at the time of assessment (state anxiety) and the general tendency to experience anxiety (trait anxiety); a 9-item Emotional Reactivity Scale, [17] designed to assess the tendency to become emotionally aroused; a 14-item Life Events Scale, [18] designed to measure actual life stressors; a 14-item Perceived Stress Scale; [18] a 13-item Life Concerns Scale used in the Saskatchewan Heart Health Study; [19] and the Perceived Stress Level questionnaire, [12, 13] designed to measure perceived stress during clinical assessment. Scales with established reliability (Cronbach's alpha 0.80 or greater) include the CES-D Scale, the Cook-Medley Hostility Scale, the Emotional Reactivity Scale, the Perceived Stress Scale and the State-Trait Anxiety Inventory. [14–17, 20] In our study the Cronbach's alpha values were as follows: CES-D scale 0.89, Cook-Medley Hostility Scale 0.84, State-Trait Anxiety Inventory 0.92, Emotional Reactivity Scale 0.90, Life Events Scale 0.51, Life Concerns Scale 0.75, Perceived Stress Scale 0.86 and Perceived Stress Level scale 0.63.

In a bivariate analysis, we used 2-tailed t-tests to test for significant differences between means for continuous variables and the chi squared test to test for significant differences for categoric variables. A p value of less than 0.05 was considered significant for all analyses. We used logistic regression to determine whether specific psychological, clinical or demographic variables predict whether treated patients with uncontrolled hypertension had a white-coat response or sustained hypertension.

## Results

A total of 103 patients (55 men and 48 women) were entered into the study, of whom 37 (36%) met the criteria for white-coat response. Eleven of the men (20%, 95% confidence interval [CI] 10%-33%) and 26 of the women (54%, 95% CI 39%-69%) had a white-coat response.

(Table 1) shows the means of the clinical, demographic and psychologic determinants for the subjects with a white-coat response and those with sustained hypertension. Of the variables examined, only female sex (p < 0.001), time (in months) since the diagnosis of hypertension (p < 0.05) and clinic systolic blood pressure (p < 0.05) were significantly different between the 2 groups.

View this table:
[Table1](http://www.cmaj.ca/content/161/3/265/T1)

Table 1. Means of clinical variables and psychometric test scores by diagnosis of whitecoat response or sustained hypertension in 103 subjects with uncontrolled hypertension

(Table 2) shows the means of the clinical, demographic and psychometric variables according to sex and diagnosis. The effect of stress in relation to the diagnosis (white-coat response or sustained hypertension) was different between men and women. Women with a white-coat response had significantly higher stress scores on the Perceived Stress Level questionnaire than women with sustained hypertension (p < 0.05). Conversely, men exhibiting a white-coat response scored lower on the Perceived Stress Scale and the CES-D Scale than men with sustained hypertension (p < 0.05).

View this table:
[Table2](http://www.cmaj.ca/content/161/3/265/T2)

Table 2. Means of clinical variables and psychometric test scores by sex and diagnosis

A difference in time since the diagnosis of hypertension between subjects with a white-coat response and those with sustained hypertension was evident only among women. The time since diagnosis was significantly longer for those in the former group than those in the latter group (273 v. 198 months) (p < 0.05). The mean clinic systolic blood pressure for men was lower in the white-coat response group than in the sustained hypertension group (p < 0.05).

The psychometric scores, drug equivalents, sex and time since diagnosis of hypertension were entered into a logistic regression model to determine a prediction Equation forwhite-coat response. Missing scores for some of the psychometric tests reduced the number of subjects to 90. We estimated separate logistic models for men and women since the effect of stress was found to be significantly different among the 2 sexes.

Perceived level of stress was a significant predictor of white-coat response in women: a woman with a higher score on the Perceived Stress Level questionnaire was more likely to exhibit this response (odds ratio [OR] per unit 7.0, 95% CI 1.3-36.0) (Table 3). Women with a long duration since the diagnosis of hypertension were more likely to exhibit a white-coat response that women with a short duration since diagnosis (OR per year 1.1, 95% CI 1.0-1.2). Using these 2 variables as a diagnostic test for white-coat response yielded a sensitivity of 77% and a specificity of 65%.

View this table:
[Table3](http://www.cmaj.ca/content/161/3/265/T3)

Table 3. Logistic regression model of selected variables for women (n = 42) and for men (n = 48)

For men, depression and clinic systolic blood pressure were entered as weak predictors of white-coat response (Table 3). Men who scored higher on the CES-D Scale were more likely to have sustained hypertension than to exhibit a white-coat response (OR per unit 1.2, 95% CI 1.0-1.5). Men whose clinic systolic blood pressure was higher were also slightly more likely to have sustained hypertension than to manifest a white-coat response (OR per mm Hg 1.1, 95% CI 1.0-1.2). Using these 2 variables as a diagnostic test for white-coat response yielded a sensitivity of 55% and a specificity of 92%.

## Interpretation

A total of 36% of our subjects whose clinic blood pressure remained high despite antihypertensive drug treatment were found to exhibit a white-coat response. Other investigators have reported prevalence rates of white-coat response of 21% to 73%. [9, 10, 21, 22] This wide range likely reflects differences in the criteria used to define white-coat response.

Several studies have suggested that white-coat hypertension is benign and that antihypertensive therapy is not required, [23–25] whereas other studies have suggested that it may not be innocent. [26–32] However, given that some normotensive subjects have ambulatory readings in the range of those seen in our white-coat group, [33] the risk of complications due to hypertension in our subjects with a white-coat response should not be great.

The sex difference in white-coat response is striking. Myers and Reeves [10] found a significant difference in the prevalence of the response between women and men. This difference persisted even after the definition of whitecoat response was changed to a difference between clinic and ambulatory blood pressure readings of at least 40/20 mm Hg. However, other studies have not demonstrated any difference in prevalence among men and women. [9, 21] In our sample, women were more than twice as likely as men to exhibit a white-coat response.

The reason for the sex difference is unclear. It may be related to a difference in perception of the purpose of the visit. MacDonald and colleagues [34] found a significant difference between diastolic blood pressure readings obtained in a situation perceived to be evaluative versus a nonevaluative situation. In any event, sex differences in white-coat response should be considered in future studies involving patients in whom hypertension is diagnosed on the basis of high clinic readings. [10] Use of qualitative methods would be appropriate to explore sex differences from the patients' perspective.

Several investigators have used psychological testing, mental stress testing, exercise testing, or examination of levels of anger, anxiety or depression to test for blood pressure variances between patients with a white-coat response and those with sustained hypertension. [6–8, 35] In our study, a lower depression score was predictive of white-coat response for men. For women, a higher perceived level of stress was predictive of such a response. Clinically, however, these differences are not enough to substitute (as diagnostic tools) for ambulatory blood pressure monitoring.

In an earlier study we found that a high perceived level of stress, as measured by the Perceived Stress Level questionnaire, was predictive of having uncontrolled versus controlled hypertension. [12] In the current study we used a second scale measuring perceived stress, the Perceived Stress Scale, [18] to validate our findings. Unexpectedly, the stratified analysis results for the 2 measures were conflicting. Men with sustained hypertension had a significantly higher perceived stress score, as measured by the Perceived Stress Scale, than men with a white-coat response, whereas women with a white-coat response had a significantly higher level of perceived stress, as measured by the Perceived Stress Level questionnaire, than women with sustained hypertension. Thus, there may be a differential response among women and men to the various scales used to measure perceived stress. It appears that women exhibit a different stress response than men to clinic visits that affects their blood pressure measurements. Perception of stress is an area that requires further study. From a practical perspective, all patients whose blood pressure remains high despite adequate antihypertensive therapy should be considered for 24-hour ambulatory blood pressure monitoring because a white-coat response cannot be predicted reliably.

We thank our research assistant, Sheila Anderson, for her work in the project.

Funding for this work was received from the Health Services Utilization and Research Commission of Saskatchewan for 1993-1995 and from the Heart and Stroke Foundation of Saskatchewan.

Competing interests: None declared.

This article has been peer reviewed.

Reprint requests to: Mary MacDonald, Rm. 434, Ellis Hall, College of Nursing, University of Saskatchewan, 107 Wiggins Rd., Saskatoon SK S7N 5E5; fax 306 966-6703; macdonaldm@sask.usask.ca

## References

1.  1. Bottini PB, Carr AA, Rhoades RB, Prisant LM. Variability of indirect methods used to determine blood pressure. Office vs mean 24-hour automated blood pressures. Arch Intern Med1992;152:139-44.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1001/archinte.1992.00400130147019&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=1728909&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1992GZ35900019&link_type=ISI) 

2.  2. Mancia G, Grassi G, Pomidossa G, Gregorini L, Bettinieri G, Parati G, et al. Effects of blood-pressure measurement by the doctor on patients' blood pressure and heart rate. Lancet1983;2:695-8.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1016/S0140-6736(83)92244-4&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=6136837&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1983RH67300001&link_type=ISI) 

3.  3. Pickering TG, Devereux RB, Gerin W, James GD, Pieper C, Schussel YR, et al. The role of behavioral factors in white coat and sustained hypertension. J Hypertens 1990;(7 Suppl):S141-7.
    
    

4.  4. Verdecchia P, Schillaci G, Boldrini F, Zampi I, Porcellati C. Variability between current definitions of 'normal' ambulatory blood pressure: implications in the assessment of white coat hypertension. Hypertension1992;20:555-62.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIyMC80LzU1NSI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

5.  5. Julius SA, Mejia K, Jones L, Krause N, Schorck C, van de Ven E, et al. "White coat" versus "sustained" borderline hypertensives in Tecumseh, Michigan. Hypertension1990;16:617-23.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIxNi82LzYxNyI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

6.  6. Lerman CE, Brody CS, Hui T, Lazaro C, Smith DG, Blum MJ. The white-coat hypertension response: prevalence and predictors. J Gen Intern Med1989;4:226-31.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=2786060&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1989U652400008&link_type=ISI) 

7.  7. Pickering TG, James GD, Boddie C, Harshfield GA, Blank S, Laragh JH. How common is white coat hypertension? JAMA1988;259:225-8.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1001/jama.1988.03720020027031&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=3336140&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1988L488400027&link_type=ISI) 

8.  8. Siegel WC, Blumenthal JA, Divine GW. Physiological, psychological, and behavioral factors and white coat hypertension. Hypertension1990;16:140-6.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIxNi8yLzE0MCI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

9.  9. Myers MG, Reeves RA. White coat phenomenon in patients receiving antihypertensive therapy. Am J Hypertens1991;4:844-9.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=1747219&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1991GK18900010&link_type=ISI) 

10. 10. Myers MG, Reeves RA. White coat effect in treated hypertensive patients: sex differences. J Hum Hypertens1995;9:729-33.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8551486&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1995RW13000004&link_type=ISI) 

11. 11. Haynes RB, Lacourciere Y, Rabkin SW, Leenen FHH, Logan AG, Wright N, et al. Report of the Canadian Hypertension Society Consensus Conference: 2. Diagnosis of hypertension in adults. CMAJ1993;149:409-18.
    
    [Abstract](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNDkvNC80MDkiO3M6NDoiYXRvbSI7czoyMDoiL2NtYWovMTYxLzMvMjY1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

12. 12. MacDonald MB, Sawatzky JE, Wilson TW, Laing GP. Lifestyle profiles of hypertensives. Can J Cardio Nurs1991;2(2):3-8.
    
    

13. 13. MacDonald MB, Sawatzky JE, Wilson TW, Laing GP. Predicting success in antihypertensive drug therapy: the importance of nondrug variables. Can J Cardiol1991;7:19-23.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=2025785&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 

14. 14. Radloff LS, Locke BZ. The Community Mental Health Assessment Survey and the CES-D Scale. In: Weissman MM, Myers JK, Ross CE, editors. Community surveys of psychiatric disorders. Vol 4 of Psychosocial epidemiology. New Brunswick (NJ): Rutgers University Press; 1986. p. 177-88.
    
    

15. 15. Cook WW, Medley DM. Proposed hostility scales for the MMPI. J Appl Psychol1954;38:414-8.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1037/h0060667&link_type=DOI) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000205235200009&link_type=ISI) 

16. 16. Spielberger CD, Gorsuch RL, Lushene R, Vagg PR, Roberts GA. Manual for the State-Trait Anxiety Inventory: STAI (form Y). Palo Alto (CA): Consulting Psychologists Press; 1983.
    
    

17. 17. Melamed S. Emotional reactivity and elevated blood pressure. Psychosom Med1987;49:217-25.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6ODoicHN5Y2htZWQiO3M6NToicmVzaWQiO3M6ODoiNDkvMy8yMTciO3M6NDoiYXRvbSI7czoyMDoiL2NtYWovMTYxLzMvMjY1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

18. 18. Cohen S, Kamarck S, Mermelstein R. A global measure of perceived stress. J Health Soc Behav1983;24:385-96.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.2307/2136404&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=6668417&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1983RZ58200008&link_type=ISI) 

19. 19. Saskatchewan Health, Department of National Health and Welfare, City of Regina Health Department, Saskatoon Community Health Unit, Heart and Stroke Foundation of Saskatchewan, University of Saskatchewan. Report of the Saskatchewan Heart Health Survey. Regina: Saskatchewan Health; 1990. p. 78-84.
    
    

20. 20. Radloff LS. The CES-D Scale: a self-report depression scale for research in the general population. Appl Psychol Meas1977;1(3):385-401.
    
    [Abstract](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NToic3BhcG0iO3M6NToicmVzaWQiO3M6NzoiMS8zLzM4NSI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

21. 21. Mansoor GA, McCabe EJ, White WB. Determinants of the white-coat effect in hypertensive subjects. J Hum Hypertens1996;10:87-92.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8867561&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1996UC21000005&link_type=ISI) 

22. 22. Pierdomenico SD, Mezzetti A, Lapenna D, Guglielmi MD, Mancini M, Salvatore L, et al. 'White coat' hypertension in patients with newly diagnosed hypertension: evaluation of prevalence by ambulatory monitoring and impact on cost of health care. Eur Heart J1995;16:692-7.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MzoiZWhqIjtzOjU6InJlc2lkIjtzOjg6IjE2LzUvNjkyIjtzOjQ6ImF0b20iO3M6MjA6Ii9jbWFqLzE2MS8zLzI2NS5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

23. 23. Pierdomenico SD, Lapenna D, Guglielmi MD, Antidormi T, Schiavoni C, Cuccurullo F, et al. Target organ status and serum lipids in patients with white coat hypertension. Hypertension1995;26:801-7.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIyNi81LzgwMSI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

24. 24. Cavallini MC, Roman MJ, Pickering TG, Schwartz JE, Pini R, Devereux RB. Is white coat hypertension associated with arterial disease or left ventricular hypertrophy? Hypertension1995;26:413-9.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIyNi8zLzQxMyI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

25. 25. Gosse P, Promax H, Durandet P, Clementy J. 'White coat' hypertension: no harm for the heart. Hypertension1993;22:766-70.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIyMi81Lzc2NiI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

26. 26. Bidlingmeyer I, Burnier M, Bidlingmeyer M, Waeber B, Brunner HR. Isolated office hypertension: a prehypertensive state. J Hypertens1996;14:327-32.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1097/00004872-199603000-00009&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8723986&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1996UJ80600009&link_type=ISI) 

27. 27. Mancia G, Parati G. Clinical significance of "white coat" hypertension. Hypertension1990;16:624-6.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6MzoiUERGIjtzOjExOiJqb3VybmFsQ29kZSI7czoxNToiaHlwZXJ0ZW5zaW9uYWhhIjtzOjU6InJlc2lkIjtzOjg6IjE2LzYvNjI0IjtzOjQ6ImF0b20iO3M6MjA6Ii9jbWFqLzE2MS8zLzI2NS5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

28. 28. Kuwajima I, Suzuki Y, Fujisawa A, Kuramoto K. Is white coat hypertension innocent? Structure and function of the heart in the elderly. Hypertension1993;22:826-31.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo4OiIyMi82LzgyNiI7czo0OiJhdG9tIjtzOjIwOiIvY21hai8xNjEvMy8yNjUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

29. 29. Cardillo C, DeFelice F, Campia U, Folli G. Psychophysiological reactivity and cardiac end-organ changes in white coat hypertension. Hypertension1993;21:836-44.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8500864&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1993LF39200013&link_type=ISI) 

30. 30. Cerasola G, Cottone S, Nardi E, D'Ignoto G, Volpe V, Mule G, et al. White-coat hypertension and cardiovascular risk. J Cardiovasc Risk1995;2:545-9.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1097/00043798-199512000-00009&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8665373&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 

31. 31. Verdecchia P, Schillaci G, Borgioni C, Ciucci A, Porcellati C. Prognostic significance of the white coat effect. Hypertension1997;29:1218-24.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTU6Imh5cGVydGVuc2lvbmFoYSI7czo1OiJyZXNpZCI7czo5OiIyOS82LzEyMTgiO3M6NDoiYXRvbSI7czoyMDoiL2NtYWovMTYxLzMvMjY1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

32. 32. Spence D. Mental stress and vascular reactivity in hypertension. Hypertens Can 1996;Sept:3-7.
    
    

33. 33. Mancia G, Sega R, Bravi C, Devito G, Valagussa F, Cesana G, et al. Ambulatory blood pressure normality: results from the PAMELA study. J Hypertens1995;13:1377-90.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=8866899&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1995TP44900003&link_type=ISI) 

34. 34. MacDonald M, Spink KS, Faulkner R. The effect of testing anxiety on blood pressure. Can J Cardiovasc Nurs1993;4:3-6.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=7848535&link_type=MED&atom=%2Fcmaj%2F161%2F3%2F265.atom) 

35. 35. Schneider RH, Egan BM, Johnson EH, Drobney H, Julius S. Anger and anxiety in borderline hypertension. Psychosom Med1986;48:242-8.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6ODoicHN5Y2htZWQiO3M6NToicmVzaWQiO3M6ODoiNDgvMy8yNDIiO3M6NDoiYXRvbSI7czoyMDoiL2NtYWovMTYxLzMvMjY1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==)