title: Validity of self-reported blood pressure control in people with hypertension attending a primary care center.
abstract: OBJECTIVE
  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.
  
  
  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 (κ=0.7); 9 and 14% of patients overestimated and underestimated the number of prescribed medications, respectively.
  
  
  CONCLUSIONS
  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 hypertension control.
authors.affiliation: Departments of aPublic Health Sciences bEmergency Medicine cFamily Medicine dSchool of Kinesiology and Health Studies, Queen's University, Kingston, Ontario eDepartments of Medicine, Community Health Sciences and of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Canada.
authors.forename: Marianne E
authors.initials: ME
authors.lastname: Gee
authors.forename: William
authors.initials: W
authors.lastname: Pickett
authors.forename: Ian
authors.initials: I
authors.lastname: Janssen
authors.forename: Norm R C
authors.initials: NR
authors.lastname: Campbell
authors.forename: Richard
authors.initials: R
authors.lastname: Birtwhistle
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods; D048909:Diabetes Complications / Q000150:complications; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D000959:Antihypertensive Agents