title: The contribution of hypertension to black-white differences in likelihood of coronary artery disease detected during elective angiography.
abstract: BACKGROUND
  Black patients in the United States undergoing angiography for suspected coronary artery disease (CAD) have consistently been found to have less disease than whites. As the effects of hypertension are greater in blacks than whites, and hypertensive heart disease may mimic CAD and lead to catheterization, we examined the association between race and hypertension as an explanation for the disparities in angiographic CAD.
  
  
  METHODS
  Using an academic hospital's institutional database, we studied patients undergoing first-time elective angiography from 2001 to 2008. Using multivariable logistic regression with data on patient demographics, CAD risk factors, and coronary stenoses, we compared rates of angiographic disease for blacks and whites, creating models separately for patients with and without hypertension. We then tested the significance of an interaction term between race and hypertension on angiographic findings.
  
  
  RESULTS
  We identified 1,203 black and 2,538 white patients who underwent initial elective angiography. Black patients were less likely to have a significant stenotic lesion (≥50% stenosis in the left main artery or ≥70% stenosis elsewhere) than whites (adjusted risk ratio 0.65; 95% confidence interval (CI) 0.55-0.75). Among patients with hypertension this difference was exaggerated (adjusted risk ratio 0.60; 95% CI 0.51-0.71). However, among patients without hypertension, the risk of having a significant lesion was similar in blacks and whites (adjusted risk ratio 0.97; 95% CI 0.67-1.37). The interaction term for race and hypertension was confirmed as statistically significant.
  
  
  CONCLUSIONS
  Among patients electively referred for angiography, hypertension, and its effects may contribute to the lower rate of CAD found in blacks compared to whites.
authors.affiliation: Department of Public Health Leadership, University of North Carolina at Chapel Hill, USA. matthew_triplette@med.unc.edu
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Triplette
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Rossi
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Viera
authors.forename: Mauricio G
authors.initials: MG
authors.lastname: Cohen
authors.forename: Donald E
authors.initials: DE
authors.lastname: Pathman
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data; D001741:Black or African American / Q000706:statistics & numerical data*; D001794:Blood Pressure; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000208:ethnology* / Q000503:physiopathology; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D006973:Hypertension / Q000208:ethnology* / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*