|Home | About | Journals | Submit | Contact Us | Français|
To provide updated, evidence-based recommendations for the diagnosis and assessment of adults with hypertension.
The diagnosis of hypertension is dependent on appropriate blood pressure measurement, the timely assessment of serially elevated readings, the degree of blood pressure elevation, the method of measurement (office, ambulatory, home) and associated comorbidities. The presence of cardiovascular risk factors and target organ damage should be ascertained to assess global cardiovascular risk and determine the urgency, intensity and type of treatment required.
MEDLINE searches were conducted from November 2007 to October 2008 with the aid of a medical librarian. Reference lists were scanned, experts were contacted, and the personal files of authors and subgroup members were used to identify additional studies. Content and methodological experts assessed studies using prespecified, standardized evidence-based algorithms. Recommendations were based on evidence from peer-reviewed full-text articles only.
Recommendations for blood pressure measurement, criteria for hypertension diagnosis and follow-up, assessment of global cardiovascular risk, diagnostic testing, diagnosis of renovascular and endocrine causes of hypertension, home and ambulatory monitoring, and the use of echocardiography in hypertensive individuals are outlined. Key messages include continued emphasis on the expedited, accurate diagnosis of hypertension, the importance of global risk assessment and the need for ongoing monitoring of hypertensive patients to identify incident type 2 diabetes.
All recommendations were graded according to strength of the evidence and voted on by the 57 members of the Canadian Hypertension Education Program Evidence-Based Recommendations Task Force. All recommendations were required to be supported by at least 70% of task force members. These guidelines will continue to be updated annually.
Fournir des recommandations probantes et à jour pour le diagnostic et l’évaluation des adultes hypertendus.
Le diagnostic d’hypertension dépend d’une mesure pertinente de la tension artérielle, de l’évaluation opportune de lectures sérielles élevées, du taux d’élévation de la tension artérielle, du mode de mesure (en cabinet, en milieu ambulatoire, à domicile) et des comorbidités connexes. Il faut évaluer la présence de facteurs de risque cardiovasculaires et l’atteinte des organes cibles afin de déterminer le risque cardiovasculaire global ainsi que l’urgence, l’intensité et le type de traitement.
Des recherches dans MEDLINE ont été exécutées entre novembre 2007 et octobre 2008 avec l’aide d’un bibliothécaire médical. On a dépouillé les listes de référence, communiqué avec des experts et utilisé les dossiers personnels des auteurs et des membres des sous-groupes pour repérer d’autres études publiées. Des spécialistes du contenu et de la méthodologie ont évalué les études au moyen d’algorithmes normalisés, probants et préétablis. Les recommandations sont fondées sur des données probantes tirées d’articles intégraux révisés par des pairs.
Le présent document contient des recommandations sur la mesure de la tension artérielle, les critères de diagnostic et de suivi de l’hypertension, l’évaluation du risque cardiovasculaire global, les tests diagnostiques, le diagnostic des causes rénovasculaires et endocriniennes de l’hypertension, la surveillance ambulatoire et à domicile et le recours à l’échocardiographie chez les hypertendus. Les principaux messages exposent l’importance d’un diagnostic rapide et exact de l’hypertension, de l’évaluation du risque global et du besoin d’assurer une surveillance continue des patients hypertendus afin de repérer les cas incidents de diabète de type 2.
Toutes les recommandations sont classées selon la solidité des données probantes, et les 57 membres du groupe de travail des recommandationsprobantesduProgrammeéducatifcanadiensurl’hypertension ont exercé leur vote à leur égard. Toutes les recommandations devaient obtenir un consensus d’au moins 70 % de la part des membres du groupe de travail. Les présentes lignes directrices continueront d’être mises à jour chaque année.
Hypertension affects 27% of the Canadian adult population 35 to 64 years of age (1), and remains one of the most common modifiable risk factors for cardiovascular disease in Canada and globally (2,3). The present document summarizes the 2009 Canadian Hypertension Education Program (CHEP) recommendations for the diagnosis and assessment of hypertension in adults, focusing on those recommendations that are new or updated. For issues related to the diagnosis and evaluation of high blood pressure in children and adolescents, the reader is referred to separate guidelines (4). A more detailed discussion of previous changes to the Canadian recommendations is available in previous publications (5–8). Summary documents of all recommendations, including downloadable slide kits, are available free of charge on the Canadian Hypertension Society Web site (www.hypertension.ca).
The previously published methodology remains unchanged (9) and was previously described (10). In brief, grade A recommendations are based on studies with high levels of internal validity, statistical precision, generalizability and clinical relevance. Grade B and C recommendations are derived from studies characterized by lower internal validity, precision or generalizability, or from studies reporting intermediate or surrogate outcomes instead of more clinically relevant ones. Grade D recommendations are based on expert opinion or studies with lower levels of internal validity or precision than grade C recommendations.
There have been no changes to these recommendations in 2009.
The criteria for the diagnosis of hypertension were previously discussed in detail (11). It should be emphasized that when using office BPs to diagnose hypertension, the thresholds given above refer to readings averaged over the specified number of visits and not just on the last visit.
Recognizing the importance of global risk assessment as a component of hypertension therapy (12), the 2006 recommendations (13) included a detailed review of risk assessment tools (14) including the Framingham Heart Study model (www.nhlbi.nih.gov/about/framingham/riskabs.htm) (15–18), the cardiovascular life expectancy model (www.chiprehab.com) (19), the United Kingdom Prospective Diabetes Study (UKPDS) model (www.dtu.ox.ac.uk/index) (20,21) and the Symptoms-Causes-Output-Resources-Effects (SCORE) model (www.scorecanada.ca) (22). Measurement of the ankle-brachial index may improve the accuracy of cardiovascular risk prediction beyond risk scoring alone (23).
Detailed guidelines for hypertension treatment based on absolute risk thresholds are not available at this time, given the lack of published studies examining the validity of these models in the Canadian population. However, global risk assessment in general, and the use of these models specifically, can be used as a tool to assist physicians in identifying subjects with hypertension who are most likely to benefit from therapy. When considering an individual’s future risk of developing cardiovascular disease and the potential impact of antihypertensive therapy, one should consider assessing both the risk of future cardiac as well as cerebrovascular events (24).
A recently published randomized clinical trial among Canadians with dyslipidemia has demonstrated that explicitly calculating a patient’s cardiovascular risk and discussing the results can significantly increase the likelihood of achieving lipid targets, even after adjustment for the intensity of statin therapy (25). This suggests that informed patients are more adherent to lifestyle recommendations and/or pharmacotherapy. Although a similar trial focusing on hypertensive management has not been completed, these results are potentially generalizable to individuals with hypertension.
As previously discussed, the routine ascertainment of microalbuminuria in all nondiabetic hypertensive patients is currently not recommended (5). However, assessment for microalbuminuria may be indicated in selected patients when a global risk assessment is being performed to identify high-risk hypertensive patients eligible for statin therapy (6,26). Assessment of microalbuminuria is also required to guide therapy in patients with diabetes and those with chronic kidney disease.
Monitoring all hypertensive patients for incident diabetes according to the recommendations outlined in the guidelines of the Canadian Diabetes Association (www.diabetes.ca) is recommended. In part, hypertensive patients are at higher risk for developing type 2 diabetes because of the tendency of cardiometabolic risk factors to cluster, particularly in the presence of central adiposity (27–29). At minimum, new-onset diabetes occurs in 1% to 2% of hypertensive patients each year (30,31). Among 18,411 nondiabetic hypertensive patients older than 55 years of age who had follow-up measurements of fasting plasma glucose (43% of the original cohort), the cumulative incidence of diabetes was 8% to 11% at four years (32). Furthermore, the prognosis of patients who develop diabetes is worse than those who do not (30–34). After 14.3 years of follow-up in the placebo arm of the Systolic Hypertension in Elderly Patients (SHEP) trial (33) (older than 60 years of age), cardiovascular mortality (hazard ratio [HR] 1.56, 95% CI 1.12 to 2.18) and total mortality (HR 1.35, 95% CI 1.05 to 1.73) were significantly increased among those who developed diabetes.
Although based on weaker evidence, the type of antihypertensive drug treatment also appears to influence future risk of type 2 diabetes (27,28). Studies suggest that both beta-blockers and thiazides are associated with an increased risk of diabetes, and angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and calcium channel blockers are neutral or associated with decreased risk (27). However, in the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) trial (35) (three-year randomized controlled trial involving 5269 prediabetic patients), ramipril did not significantly reduce the incidence of type 2 diabetes (HR 0.91, 95% CI 0.81 to 1.03) or mortality. Thus, no specific antihypertensive drugs are currently recommended to prevent the development of diabetes mellitus.
It is important to note that there are currently no conclusive data that directly implicate drug-induced type 2 diabetes with increased cardiovascular risk (33). Furthermore, in patients with or without diabetes, thiazide-based treatment regimens reduce cardiovascular and overall mortality to a similar extent as ‘nondiabetogenic’ agents (6). The task force will continue to monitor this area closely and issue updated recommendations as required.
There are no changes from the 2008 recommendations (7). Most diagnostic testing for renovascular hypertension has been validated in patients with normal renal function. In patients with CKD, there are notable limitations to current screening methods and the optimal method is uncertain. The diagnostic accuracy of captopril renal scanning is poor in the setting of GFR levels below 60 mL/min (36). Nephrogenic systemic fibrosis may very rarely occur (estimated incidence one per million) in patients receiving gadolinium-based contrast media for magnetic resonance angiography. The risk may vary by contrast agent and is higher in patients with CKD (particularly those with end-stage renal failure); similarly, computed tomographic angiography carries a risk of contrast nephropathy (37). Duplex Doppler ultrasonography of the renal vessels is safe, but is highly specialized, operator-dependent and not widely available (38).
There are no changes to these recommendations in 2009.
Information on validated blood pressure monitors can be found at <www.hypertension.ca/chep/approved-home-bp-devices>. There are no changes to these recommendations for 2009.
There are no new recommendations in this section.
This section was updated in 2006 (13) and there are no new changes in 2009.
The CHEP Recommendations Task Force will continue to monitor the published literature and update these guidelines annually based on new developments in the literature and feedback from stakeholders and other users of these recommendations.