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Independent predictors of isolated clinic ('white-coat') hypertension
P Verdecchia1, P Palatini, G Schillaci
1Cardiologia e Fisiopatologia Cardiovascolare and Medicina Interna, Universiá di Perugia, Italy. verdec@tin.it
Insights
Isolated clinic hypertension (ICH) is more common in women, nonsmokers, and those with lower clinic blood pressure and smaller left ventricular mass. These factors help identify patients needing ambulatory blood pressure monitoring.
Area of Science:
- Cardiology
- Hypertension Research
- Diagnostic Medicine
Background:
- Guidelines recommend 24-hour ambulatory blood pressure (ABP) monitoring for suspected isolated clinic hypertension (ICH).
- Pre-test probability estimation for ICH using independent predictors in mildly hypertensive individuals is lacking.
Purpose of the Study:
- To identify independent predictors of isolated clinic hypertension (ICH) in individuals with mild hypertension.
Main Methods:
- A cohort of 1564 untreated stage I hypertension patients underwent 24-hour ABP monitoring and echocardiography.
- Exclusion criteria included diabetes, hypertension grade > I, renal failure, or prior cardiovascular events.
- Multivariate logistic regression analyzed predictors of ICH, defined as daytime ABP < 130/80 mmHg.
Main Results:
- The prevalence of ICH was 10.4%.
- Independent predictors of ICH included female sex, non-smoking status, lower clinic diastolic blood pressure, and smaller left ventricular (LV) mass.
- LV mass was significantly lower in patients with ICH compared to those with ambulatory hypertension and healthy controls.
Conclusions:
- In untreated stage I hypertension, ICH is more prevalent in women, non-smokers, and individuals with lower clinic blood pressure and reduced LV mass.
- These findings aid in identifying patients who would benefit from ambulatory blood pressure monitoring due to suspected ICH.
Background:
Hypertension guidelines recommend 24 h ambulatory blood pressure (ABP) monitoring in hypertensive subjects with suspected isolated clinic hypertension (ICH). However, the pre-test probability of ICH based on the distribution of its independent predictors has not yet been estimated in hypertensive subjects with mildly elevated blood pressure.
Objective:
To ascertain the independent predictors of ICH in mildly hypertensive subjects.
Methods:
In the setting of the HARVEST-PIUMA collaboration, we studied 1564 subjects with hypertension stage I. At entry, all subjects were untreated and all underwent ABP monitoring and echocardiography. Diabetes, hypertension grade > I, renal failure or previous cardiovascular morbid events were exclusion criteria. Clinic BP was 143/92 mmHg (SD 9/5) and 24 h ABP was 128/81 mmHg (SD 10/8).
Results:
Prevalence of ICH (daytime ABP < 130 mmHg systolic and 80 mmHg diastolic) was 10.4%. In a multivariate logistic regression analysis, sex (P = 0.002), smoking (P = 0.038) and clinic diastolic BP (P = 0.0002) were the sole independent predictors of ICH according to the following equation: Y = 2.6438 + 0.5128 x sex (0 = men; 1 = women) + 0.4543 x current smoking (0 = yes; 1 = no) - 0.0531 x clinic diastolic BP (mmHg) and P (probability of ICH) = exp(Y)/[1 + (exp(Y)]. Left ventricular (LV) mass at echocardiography was a further independent predictor (P = 0.002) of ICH according to the following equation: Y= 3.4343 + 0.4603 x sex + 0.5989 x current smoking - 0.0482 x clinic diastolic BP - 0.0312 x LV mass [g/height (m)2.7]. LV mass was greater (P < 0.01) in the group with ambulatory hypertension [42.3 g/height (m)2.7] than in that with ICH [39.2 g/height (m)2.7] and not dissimilar between the ICH group and a control group of 370 healthy normotensive subjects [38.1 g/height (m)2.7].
Conclusions:
In untreated subjects with stage I hypertension, ICH is most frequent among women, nonsmokers and subjects with low clinic BP and smaller LV mass. These findings allow identification of subjects with indication to ABP monitoring because of suspected ICH.