Chronology poorly predicts biological age (BA) or physiologic reserve (PR). An objective approach to the heterogeneity of aging would greatly help clinical decision making in the elderly.
The first pilot study evaluated 130 "healthy" volunteers, ages 70 to 95 years. A summary BA/PR index was developed, using measures of endurance, strength, flexibility, balance, cognition, depression, comorbidity, and exercise. The second study applied the BA/PR concept to prediction of death after a first elective coronary artery bypass graft, using a Veterans Administration database.
The BA/PR index was a better predictor of 3-year functional outcomes and death than was chronological age. In the coronary artery bypass graft study, the inclusion of BA/PR variables significantly improved prediction of 6-month and long-term death for Veterans Administration patients.
The usefulness of a biological age (BA/PR) approach in predicting outcomes in the elderly was supported. Needed research should develop tools for routine "tracking" of the aging process.