Hypertension Surveillance in Canada: Minimum Standards for Assessing Blood Pressure in Surveys

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ABSTRACT

The last Canadian survey that accurately assessed hypertension treatment and control is over 12 years old. The survey indicated that only 13% of adults with hypertension were treated and controlled. Statistics Canada has announced a new survey that will measure health risks in 2007-2008. A committee of hypertension and survey experts was formed to provide recommendations to ensure the survey would address the minimum surveillance needs of the hypertension community. The committee made several innovative recommendations to improve the reproducibility and standardization of blood pressure assessment. In particular, it was recommended to adopt oscillometric measurement and to have measurements conducted in the absence of study personnel. Continued use of standard Canadian survey questions to assess awareness and treatment of hypertension was recommended to allow comparison with prior surveys. It was also recommended that Canada adopt a specific question on lifestyle changes. The new survey will allow the Canadian hypertension community, and in particular the Canadian Hypertension Education Program, to evaluate the effectiveness of current programs for prevention, treatment and control of hypertension and to revise our strategies based on the results.

MeSH terms: Hypertension; blood pressure; population surveillance; public health; surveys; blood pressure determination; sphygmomanometers

High blood pressure is estimated to be the leading risk factor for death in women and the second leading risk factor in men in many industrialized countries, including Canada.1 However, the latest reliable national data on hypertension prevalence, awareness, treatment and control come from a survey conducted between 1985 and 1992.2 When the Canadian survey data were compared to similar data from the United States (US), hypertension prevalence was similar between the two countries (20.1% vs. 21.1% of Canadian and American adults, respectively) but awareness of diagnosis (69% vs. 57%), treatment of hypertension (52% vs. 34%) and treatment and control rates (25% vs. 13%) were substantially higher in the US than in Canada.2 More recent data from the US show a further improvement in treatment and control rates.3 The Canadian Hypertension Education Program (CHEP) was initiated in 1999 to improve treatment and control of hypertension in Canada.4,5

Statistics Canada plans to survey major health risks of Canadians starting in 2007. A committee was established by the Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, and the Heart and Stroke Foundation of Canada with the purpose of 1) establishing the minimum and desirable criteria, and 2) devising the methodology for assessing blood pressure in Canadian surveys. Published standardized blood pressure survey methodology will enable the planning of future studies within Canada, and perhaps internationally, the results of which can be compared. This commentary provides a brief overview of the full committee report6 found at www.hypertension.ca, and represents a step in the process toward developing accepted standards for assessing blood pressure in surveys.

The recommendations were developed in the setting of evolving technology and foreseeable bans on mercury-containing devices in the measurement of blood pressure. Furthermore, recommendations were devised to allow reliable analysis of time trends in hypertension prevalence, awareness, treatment and control rates. The Committee consisted of 19 Canadian experts in measurement of blood pressure, epidemiology of hypertension and hypertension surveys.* The Committee reviewed a Health Canada report on the epidemiology of hypertension in Canada that examined methods used in previous Canadian as well as other countries' national surveys, and considered the annually updated evidence-based recommendations on assessment and follow-up of blood pressure from the CHEP.

Canada has an excellent system of administering regular questionnaire surveys on health risk factors such as hypertension and disease. …