CHICAGO — A risk index for patients with peripheral arterial disease stratifies patients into four risk categories with substantially different mortality risks.
The risk categories were first defined with a derivation cohort of 1,498 patients, and then were confirmed by a separate validation cohort of 1,144 patients, Dr. Harm H. Feringa and his associates reported in a poster at the annual scientific sessions of the American Heart Association.
The risk index developed by the researchers included 13 elements and it “may be useful for patient counseling and medical decision making,” Dr. Feringa, who is a physician at Erasmus Medical Center in Rotterdam, the Netherlands, and his associates wrote in the poster.
The peripheral arterial disease (PAD) patients in the derivation and validation cohorts were stratified by their clinical characteristics at baseline, and their outcomes were tracked during an average follow-up of 8 years.
The overall estimated 10-year mortality was 42% among all patients in the derivation group and 40% among patients in the validation group.
Based on a multivariate analysis of many clinical measures, the researchers focused on 13 baseline features for the risk index.
Ten elements represented mortality risks and were tallied as added points to the risk index.
The other three elements were protective, and subtracted points from the risk score (see box).
To create and assess the risk score, the researchers divided the derivation and validation cohorts into four different risk strata.
Low risk were those with scores of less than zero; low intermediate risk were those with scores of 0–5; high intermediate risk had scores of 6–9; and high risk patients had scores of more than 9.
In the derivation cohort, the 10-year mortality was about 20% for patients in the low group. It was about 30% for those in the low intermediate group, about 40% for patients in the high intermediate group.
Mortality was about 70% for the highest-risk patients.
The validation mortality was very similar: about 15% in the low group, 25% in the low intermediate patients, 40% in the high intermediate patients, and about 65% in the highest-risk patients.
The Index Weighs Thirteen Features