Clinical methods and pathophysiology 19
Validity of self-reported blood pressure control in people with hypertension attending a primary care center Marianne E. Geea, William Picketta,b, Ian Janssena,d, Norm R.C. Campbelle and Richard Birtwhistlea,c Objectives The aim of this study was to estimate the validity of self-reported blood pressure control and medication use in people with hypertension, with and without diabetes. Methods In a sample of 161 patients with hypertension in a family health team in Ontario, we applied questions from the 2009 Survey on Living with Chronic Disease in Canada Hypertension Component and compared responses against objectively measured and chart-abstracted clinical indicators. Objective blood pressure control was defined as a blood pressure of less than 130/80 mmHg and less than 140/90 mmHg for individuals with and without diabetes, respectively.
Conclusion Although most individuals with controlled hypertension reported having controlled blood pressure, a large proportion of individuals with uncontrolled hypertension also reported that their blood pressure was controlled. This level of misclassification suggests that in a family medicine clinic population and in health survey contexts, a self-reported measure of blood pressure control may not be useful for assessing c 2014 hypertension control. Blood Press Monit 19:19–25 Wolters Kluwer Health | Lippincott Williams & Wilkins. Blood Pressure Monitoring 2014, 19:19–25 Keywords: blood pressure, hypertension, self-report, validation studies
Results Self-reported blood pressure control showed reasonable sensitivity (83±11 and 78±10%) but low specificity (30±19 and 58±21%) in people with and those without diabetes, respectively. In the subgroup with diabetes, specificity improved to 88±11% when blood pressure control was defined on the basis of a 140/90 mmHg target. Self-reported and chart-abstracted numbers of prescribed antihypertensive medications showed fair agreement (j = 0.7); 9 and 14% of patients overestimated and underestimated the number of prescribed medications, respectively.
Departments of aPublic Health Sciences, bEmergency Medicine, cFamily Medicine, dSchool of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario and eDepartments of Medicine, Community Health Sciences and of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Canada
Introduction
asked whether their blood pressure was generally wellcontrolled, borderline, high, or low, as well as about the number of medications taken for high blood pressure and the timing of their most recent clinic blood pressure assessment. It remains unclear, however, whether these measures can be used to accurately assess blood pressure control, medication use, and recent blood pressure assessments.
Surveillance and monitoring of blood pressure and hypertension are critical factors in the effort to prevent and control hypertension [1]. Population-based surveys that use objective blood pressure measurements, such as the US National Health and Nutrition Examination Survey and the Canadian Health Measures Survey, provide a much needed picture of the prevalence, awareness, treatment, and control of high blood pressure [2–4]. In some settings, such as telephone surveys, objective blood pressure measurements are not feasible and self-reported measures of blood pressure control have been used as an alternative [5], as such reports could theoretically allow risk factors for and outcomes of uncontrolled high blood pressure to be examined. For example, in 2009, the Canadian federal government fielded the national telephone-administered Survey on Living with Chronic Disease in Canada to assess the knowledge, attitudes, and behaviors of Canadians with hypertension [5]. Among the many items measured as a part of the telephone interview [6], participants were c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 1359-5237
Correspondence to Richard Birtwhistle, 220 Bagot St, Kingston, Ontario K7L 3N6, Canada Tel: + 1 613 533 9303; fax: + 1 613 533 9302; e-mail: [email protected] Received 6 May 2013 Revised 10 September 2013 Accepted 19 November 2013
To date, no study has considered the accuracy of a simple self-reported interview question in assessing blood pressure control in patients with hypertension. Although a number of studies have compared self-recorded home blood pressure readings with those recorded objectively using a home blood pressure monitor [7–9] or with those measured in a clinic [10], the results do not foster a better understanding of the extent to which individuals with hypertension can accurately report their general level of blood pressure control in an interview setting. Thus, the primary objective of the current study was to estimate the validity of self-reported blood pressure control, as assessed in the national survey protocol [6], DOI: 10.1097/MBP.0000000000000018
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
20 Blood Pressure Monitoring 2014, Vol 19 No 1
in people with hypertension with and without diabetes (as clinically recommended blood pressure targets differ between these groups in some countries such as Canada, i.e.,
Validity of self-reported blood pressure control in people with hypertension attending a primary care center Marianne E. Geea, William Picketta,b, Ian Janssena,d, Norm R.C. Campbelle and Richard Birtwhistlea,c Objectives The aim of this study was to estimate the validity of self-reported blood pressure control and medication use in people with hypertension, with and without diabetes. Methods In a sample of 161 patients with hypertension in a family health team in Ontario, we applied questions from the 2009 Survey on Living with Chronic Disease in Canada Hypertension Component and compared responses against objectively measured and chart-abstracted clinical indicators. Objective blood pressure control was defined as a blood pressure of less than 130/80 mmHg and less than 140/90 mmHg for individuals with and without diabetes, respectively.
Conclusion Although most individuals with controlled hypertension reported having controlled blood pressure, a large proportion of individuals with uncontrolled hypertension also reported that their blood pressure was controlled. This level of misclassification suggests that in a family medicine clinic population and in health survey contexts, a self-reported measure of blood pressure control may not be useful for assessing c 2014 hypertension control. Blood Press Monit 19:19–25 Wolters Kluwer Health | Lippincott Williams & Wilkins. Blood Pressure Monitoring 2014, 19:19–25 Keywords: blood pressure, hypertension, self-report, validation studies
Results Self-reported blood pressure control showed reasonable sensitivity (83±11 and 78±10%) but low specificity (30±19 and 58±21%) in people with and those without diabetes, respectively. In the subgroup with diabetes, specificity improved to 88±11% when blood pressure control was defined on the basis of a 140/90 mmHg target. Self-reported and chart-abstracted numbers of prescribed antihypertensive medications showed fair agreement (j = 0.7); 9 and 14% of patients overestimated and underestimated the number of prescribed medications, respectively.
Departments of aPublic Health Sciences, bEmergency Medicine, cFamily Medicine, dSchool of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario and eDepartments of Medicine, Community Health Sciences and of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Canada
Introduction
asked whether their blood pressure was generally wellcontrolled, borderline, high, or low, as well as about the number of medications taken for high blood pressure and the timing of their most recent clinic blood pressure assessment. It remains unclear, however, whether these measures can be used to accurately assess blood pressure control, medication use, and recent blood pressure assessments.
Surveillance and monitoring of blood pressure and hypertension are critical factors in the effort to prevent and control hypertension [1]. Population-based surveys that use objective blood pressure measurements, such as the US National Health and Nutrition Examination Survey and the Canadian Health Measures Survey, provide a much needed picture of the prevalence, awareness, treatment, and control of high blood pressure [2–4]. In some settings, such as telephone surveys, objective blood pressure measurements are not feasible and self-reported measures of blood pressure control have been used as an alternative [5], as such reports could theoretically allow risk factors for and outcomes of uncontrolled high blood pressure to be examined. For example, in 2009, the Canadian federal government fielded the national telephone-administered Survey on Living with Chronic Disease in Canada to assess the knowledge, attitudes, and behaviors of Canadians with hypertension [5]. Among the many items measured as a part of the telephone interview [6], participants were c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 1359-5237
Correspondence to Richard Birtwhistle, 220 Bagot St, Kingston, Ontario K7L 3N6, Canada Tel: + 1 613 533 9303; fax: + 1 613 533 9302; e-mail: [email protected] Received 6 May 2013 Revised 10 September 2013 Accepted 19 November 2013
To date, no study has considered the accuracy of a simple self-reported interview question in assessing blood pressure control in patients with hypertension. Although a number of studies have compared self-recorded home blood pressure readings with those recorded objectively using a home blood pressure monitor [7–9] or with those measured in a clinic [10], the results do not foster a better understanding of the extent to which individuals with hypertension can accurately report their general level of blood pressure control in an interview setting. Thus, the primary objective of the current study was to estimate the validity of self-reported blood pressure control, as assessed in the national survey protocol [6], DOI: 10.1097/MBP.0000000000000018
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
20 Blood Pressure Monitoring 2014, Vol 19 No 1
in people with hypertension with and without diabetes (as clinically recommended blood pressure targets differ between these groups in some countries such as Canada, i.e.,
