New Index Can Stratify Mortality Risk of Patients With PAD

By Mitchel L. Zoler

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 "may be useful for patient counseling and medical decision making," said Dr. Feringa, a physician at Erasmus Medical Center in Rotterdam, the Netherlands, and his associates in the poster.

The peripheral arterial disease 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% in the validation group.

THE MORTALITY RISK INDEX INCLUDED 13 ELEMENTS AND 'MAY BE USEFUL FOR PATIENT COUNSELING AND MEDICAL DECISION MAKING.

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 risk strata: low, those with scores of less than zero; low intermediate, those with scores of 0-5; high intermediate, with scores of 6-9; and high, patients with scores of more than 9.

In the derivation cohort, the 10-year mortality was about 20% for patients in the low group, about 30% for those in the low intermediate group, about 40% for patients in the high intermediate group, and 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.

When asked to comment on this article, Dr. Magruder C. Donaldson, chairman, department of surgery, MetroWest Medical Center, Framingham, Mass., stated: "Though data such as these may not be directly applicable to individual patients, the findings reinforce the fact that we are still working in a palliative context in many clinical circumstances.

"Vascular surgeons remain thoroughly accustomed to this reality despite improvements in prevention and treatment of vascular disease. Exercise of balanced judgment and pursuit of sensible goals with regard to each patient's problem will always be strong characteristics of vascular care," he added.

"Given their broad and deep grounding in vascular disease, surgeons have a unique role in providing ongoing leadership in this regard," concluded Dr. Donaldson, who is also associate professor of surgery, Brigham \& Women's Hospital, Harvard Medical School, Boston.