An elevated level of C-reactive protein is an independent risk factor for development of heart disease in people 65 years of age or older, raising the risk of myocardial infarction in the next 10 years, according to an article in the June 28th issue of Circulation.

“The C-reactive protein test can provide useful information beyond standard risk assessment in the elderly,” said lead author Mary Cushman, MD, MSc. Cushman said the current study was the first long-term prospective study to assess C-reactive protein and risk for myocardial infarction in the elderly. Shorter-term studies had had conflicting results.

The current study followed 3971 people age 65 years or older who participated in the Cardiovascular Health Study, an observational study investigating risk factors for heart disease in the elderly.

At baseline, 26 percent of participants had elevated C-reactive protein levels, defined as greater than 3 mg/L. During 10 years of follow-up, 547 people had a nonfatal myocardial infarction or died from coronary heart disease. Participants with baseline elevation in C-reactive protein had a 45-percent increase in risk for the cardiac endpoints.

Researchers also compared their results with information from the conventional Framingham risk score, which assigns point values to risk factors such as hypertension, total cholesterol, high-density lipoprotein cholesterol, age, and smoking history.

In men predicted to have a 10 to 20 percent chance (intermediate risk) of a coronary event over the next 10 years based on Framingham score, men with an elevated C-reactive protein level had an actual rate of 32 percent. Interestingly, the actual rate was 17 percent for those with a low C-reactive protein level.

Among men at high risk per Framingham scoring (greater than 20 percent risk), the actual rate in men with elevated C-reactive protein was 41 percent compared with 23 percent for men with low C-reactive protein levels.

In women with a predicted rate of greater than 20 percent in 10 years per Framingham scoring, women with a high C-reactive protein level had an actual rate of 31 percent; women with a low C-reactive protein level had a rate of only 16 percent.

“The findings add information to the growing body of evidence on the usefulness of C-reactive protein measurements in assessing cardiovascular disease risk,” said Cushman.