Study Quantifies Lifetime Risk of Peripheral Artery Disease

Results of a new study from the Johns Hopkins Bloomberg School of Public Health are offering cardiologists and physicians new perspective as investigators claim it is the first to quantify the lifetime risk for peripheral artery disease (PAD).

The study revealed that 30% of black men and women were estimated to develop PAD during their lifetime while whites and Hispanics had prevalence rates estimated at 20%.

"A key finding in our study is that blacks have a significantly higher PAD risk than whites and Hispanics, even though current clinical guidelines don't list race as a contributing factor," said lead investigator Kunihiro Matsushita, MD, PhD, associate professor in the Department of Epidemiology at the Bloomberg School. "PAD clinical guidelines recommend considering the assessment of PAD among high-risk individuals, but our study highlights the importance of taking into account race in this context."

In an effort to explore lifetime risk estimates of lower-extremity PAD, investigator used data from 6 US community-based cohorts and vital statistics to estimate the prevalence and incidence of PAD at each year of life from birth until 80 in for white, black, and Hispanic men and women. Investigators defined PAD as an ankle-brachial index less than 0.90.

Subsequently, Markov Monte Carlo simulations in a simulated cohort of 100,000 individuals was used to estimate the lifetime risk of PAD. Investigators created a calculator that provided residual lifetime risk of PAD based on odds ratios of PAD for risk factors including diabetes mellitus and smoking.

From the 6 cohorts included in the study, a total of 38154 participants were identified. Of the 38154 included, 6.6% had PAD based on the investigators definition of an ankle-brachial index greater than 0.90

Upon analyses, investigators found that the lifetime risk of developing PAD was 30% in black men and 27.6% in black women. White men and women had a lifetime risk of 19% while Hispanic men and women had a lifetime risk of 22%.

When accounting for other risk factors, age remained a strong predictor of PAD with an adjusted hazard ratio of 1.47 (95% CI, 1.43-1.52). Women had slightly higher odds of having an ankle-brachial index less than 0.90 than men. When comparing ethnicity, investigators found that blacks had higher odds than whites while Hispanics had the lowest odds.

Investigators concluded that 9% of blacks were estimated to develop PAD by the age of 60 while the same proportion was seen at 70 years of age in whites and Hispanics. Residual lifetime risk within the same ethnicity varied by 3.5- to 5-fold according to risk factors. Investigators noted that residual lifetime risk in 45-year-old black men was 19.9% when current smoking, diabetes mellitus, and history of cardiovascular disease were absent compared to 70.4% when all were present.

This study, “Lifetime Risk of Lower-Extremity Peripheral Artery Disease Defined by Ankle-Brachial Index in the United States,” was published online in the Journal of the American Heart Association.