title: Variability in performance measures for assessment of hypertension control.
abstract: BACKGROUND
  Definitions of multiple performance measures exist for the assessment of blood pressure control; however, limited data on how these technical variations may affect actual measured performance are available.
  
  
  METHODS
  We evaluated patients with hypertension followed routinely by cardiologists at Duke University Health System from 2009 to 2010. Provider hypertension control was compared based on reading at the last clinic visit vs the average blood pressure across all visits. The impact of home blood pressure measurements and patient exclusions endorsed by the American Heart Association, the American College of Cardiology, and the Physician Consortium for Performance Improvement were evaluated using medical record reviews.
  
  
  RESULTS
  Among 5,552 hypertensive patients, the rate of blood pressure control based on last clinic visit was 69.1%; however, significant clinic-to-clinic variability was seen in serial clinic blood pressure measurements in individual patients (average 18 mm Hg). As a result, provider performance ratings varied considerably depending on whether a single reading or average blood pressure reading was used. The inclusion of home blood pressure measurements resulted in modestly higher rates of blood pressure control performance (+6% overall). Similarly, excluding patients who met guideline-recommended exclusion criteria increased blood pressure control rates only slightly (+3% overall). In contrast, excluding patients who were on 2 or more antihypertensive medications would have raised blood pressure control rates to 96% overall.
  
  
  CONCLUSIONS
  Depending on definitions used, overall and provider-specific blood pressure control rates can vary considerably. Technical aspects of blood pressure performance measures may affect perceived quality gaps and comparative provider ratings.
authors.affiliation: Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA. navar006@mc.duke.edu
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Navar-Boggan
authors.forename: Bimal R
authors.initials: BR
authors.lastname: Shah
authors.forename: Joel C
authors.initials: JC
authors.lastname: Boggan
authors.forename: Judith A
authors.initials: JA
authors.lastname: Stafford
authors.forename: Eric D
authors.initials: ED
authors.lastname: Peterson
mesh_terms: D000368:Aged; D000553:Ambulatory Care / Q000639:trends; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D012189:Retrospective Studies; D014481:United States
chemical_list: D000959:Antihypertensive Agents