Prognostic value of estimated functional capacity incremental to cardiac biomarkers in stable cardiac patients

Background-Few studies have investigated functional capacity self-assessment tools in either prediction of future major adverse cardiac outcomes beyond all-cause mortality or direct comparisons with clinically available biomarkers. Methods and Results-We estimated functional capacity using the Duke Activity Status Index (DASI) questionnaire in 8987 sequential stable patients without acute coronary syndrome who were undergoing elective diagnostic coronary angiography with 3-year follow-up of major adverse cardiac events (death, nonfatal myocardial infarction, or stroke). A low DASI score provided independent prediction of a 4.8-fold increase in future risk of incident major adverse cardiac events at 3 years (quartiles 1 versus 4 hazard ratio [95% CI] 4.76 [4.03 to 5.61], P<0.001), and a 3.8-fold increased risk after adjusting for traditional risk factors (3.77 [3.15 to 4.51], P<0.001). The prognostic value of the DASI score was evident in both primary and secondary prevention cohorts, with and without heart failure, as well as high and low C-reactive protein and B-type natriuretic peptide levels. The DASI score reclassified 15% of patients (P<0.001) beyond traditional risk factors in predicting future MACE. Conclusion-A simple self-assessment tool of functional capacity in stable patients undergoing elective diagnostic cardiac evaluation provides independent and incremental prognostic value for prediction of both significant coronary angiographic disease and long-term adverse clinical events.