The sample population for this study was selected from an initial cohort of 4,736 persons (57% female and 14% black) participating in a 5-year prospective study designed to test whether drug treatment of isolated systolic hypertension (ISH) in older adults reduces the risk of total stroke. The participants were followed monthly until systolic blood pressure (SBP) reached predetermined goals or until the maximum level of stepped care treatment was reached. The primary endpoint of the trial was total stroke, secondary endpoints included sudden cardiac death, rapid cardiac death, and nonfatal MI. The incident cases of Coronary Heart Disease (CAD) were those who experienced a nonfatal or fatal MI, underwent coronary artery bypass grafting (CABG) or coronary artery angioplasty (PTCA), or developed angina during the study.

There were 432 incident cases (9.1% of the SHEP cohort). Of these patients, 25 (5.9%) underwent PTCA and 52 (12.2%) underwent CABG. The findings indicated that “factors significantly (P# 0.05) associated with an increased use of CABG and PTCA in univariate analysis included younger age, male sex, and being married.” In a multivariate analysis, gender and age remained significantly associated with procedural intervention. Though the results were not statistically significant, black race (with the exception of the <75 year-old group) was associated with a decreased likelihood of undergoing a procedure. The investigators report, “Eighteen percent of white participants with incident CHD underwent either procedure compared with 14.6% of black participants (P=0.561). Among participants less than 75 years of age, 22.3% of whites underwent such intervention, compared with 22.6% of blacks (P=0.975). For those 75 and older, 13.0% of white participants underwent an intervention while none of 17 black participants did (P=0.114).” They state in their discussion that “it is likely that the sample size of blacks in the current study was too small to adequately address racial differences in CV procedure use.” However, although the difference did not reach statistical significance, a logistic regression analysis of use of PTCA and CABG revealed an RR of 1.05 (95% CI of 0.40-2.71). The authors state that the difference “could be still important given the 95% confidence intervals for racial differences in use.”

The results of this study must be interpreted with caution given that it is a secondary analysis of a defined cohort. Variables that could have influenced the use of CABG and PTCA were not available (for example, results of cardiac catheterization, insurance status, and ventricular function). Another notable limitation is that, within the already small number of participants that underwent intervention (the unit of analysis of the study), the number of black patients may have been too small to detect significance.