Relationship between individual socioeconomic variables and the prevalence of different procedures.

**<p>Strong correlation, Pearson's correlation coefficient.</p><p>A correlation matrix was established for various procedures (column 1) and socioeconomic factors (columns 2–4). A Pearson's correlation coefficient was established for each relationship. A negative value indicates a negative correlation. Value ranges of 0–0.09, 0.1–0.3, 0.31–0.5, and 0.51–1.0 were considered to have no, small, medium, and strong correlations, respectively. CABG and PTCA had a strong negative correlation with both education and income.</p><p>Socioeconomic Factors Key.</p><p>Employment = unemployed for greater than one year.</p><p>Education = having more than a high school education.</p><p>Income = household income greater than $ 50,000 USD.