Applying the 2005 Canadian Hypertension Education Program recommendations: 1. Diagnosis of hypertension

• Published in: Canadian Medical Association journal (CMAJ) 2005-08, Vol.173 (5), p.480-483
• Main Authors: Bolli, Peter, Myers, Martin, McKay, Donald
• Format: Article
• Language: English
• Subjects: Aged; Algorithms; Antihypertensive Agents - therapeutic use; Canada; Care and treatment; Diagnosis; Diagnosis, Differential; Education; False Positive Reactions; Female; Health education; Humans; Hypertension; Hypertension - diagnosis; Male; Medical diagnosis; Medical treatment; Middle Aged; Practice Guidelines as Topic
• ISSN: 0820-3946; 1488-2329
• DOI: 10.1503/cmaj.050184

Hypertension is estimated to be the third leading cause of death worldwide. Although 22% of adult Canadians have hypertension, only 16% have it controlled with drug therapy1 even though numerous studies have proven the benefit of lowering blood pressure. A recent study showed that a delay of 3 months in effective blood pressure control in high-risk patients (those with evidence of target organ damage, diabetes mellitus, chronic kidney disease or macrovascular damage) is associated with at least a 2-fold increase in cardiovascular morbidity and mortality.2 Therefore, the 2005 Canadian Hypertension Education Program recommandations3 have been revised to expedite diagnosis in adults by (a) reducing the number of visits needed to establish the presence of hypertension in high-risk patients and in those with severe (stage 2) hypertension and (b) introducing the option of using self/home or ambulatory blood pressure monitoring in making the diagnosis. Comment: Yes. Because this patient's systolic blood pressure remains above 180 mm Hg, hypertension can now be diagnosed (Fig. 1).3 The greatest fall in blood pressure occurs between the first and second visits. The power to distinguish between patients with and those without hypertension is 80% between visits 1 and 2, and a further 10% between visits 2 and 3. Thereafter, fluctuations in blood pressure are mainly random.4 Therefore, it is unlikely that this patient's blood pressure would be normal on further visits. Persistent systolic blood pressure readings greater than 180 mm Hg (or diastolic readings greater than 110 mm Hg) represent severe hypertension, and delaying treatment may increase the risk of a cardiovascular event. If this patient was at high risk (had evidence of target organ damage, diabetes, chronic kidney disease or macrovascular damage), the diagnosis would have applied even if his blood pressure was above 140/90 mm Hg over 2 visits (Fig. 1).2 The patient wants to be absolutely sure that her blood pressure is indeed normal and agrees to undergo ambulatory blood pressure monitoring. This method gives a daytime (awake) mean blood pressure reading of 128/70 mm Hg and a 24-hour mean reading of 120/64 mm Hg, which confirms the diagnosis of office-induced hypertension. The patient is asked to return in 6 months' time for repeat ambulatory blood pressure monitoring and at yearly intervals thereafter, since office-induced hypertension may subsequently progress to hypertension.5 If the patient requires ant