Development of a frailty index for patients with coronary artery disease.

Objectives: To construct a brief frailty index for older patients with coronary artery disease (CAD) undergoing coronary angiography that includes physical, cognitive, and psychosocial criteria and accurately predicts future disability and decline in health-related quality of life (HRQL).

Design: Prospective cohort.

Setting: An urban tertiary care hospital in Alberta, Canada.

Participants: Three hundred seventy-four patients aged 60 and older (73% male) undergoing cardiac catheterization for CAD between October 2003 and May 2007.

Measurements: Potential frailty criteria examined at baseline (before the procedure) included measures of balance, gait speed, cognition, self-reported health, body mass index (BMI), depressive symptoms, and living alone. The outcomes assessed over 1 year were dependency in activities of daily living (ADLs) and HRQL.

Results: The five best-fitting criteria from regression analyses for ADL decline were poor balance (risk ratio (RR)=2.4, 95% confidence interval (CI)=1.4–4.0), abnormal BMI (RR=1.8, 95% CI=1.1–3.0), impaired Trail-Making Test Part B performance (RR=2.3, 95% CI=1.3–4.2), depressive symptoms (RR=1.8, 95% CI=1.1–3.1), and living alone (RR=2.2, 95% CI=1.3–3.8). Using the five criteria as separate variables or as a summary frailty index yielded identical areas under the receiver operating characteristic curve (0.76, 95% CI=0.66–0.84). Patients with three or more criteria (vs none) were at statistically significant greater risk for increased disability (RR=10.4, 95% CI=4.4–24.2) and decreased HRQL (RR=4.2, 95% CI=2.3–7.4) after 1 year.

Conclusion: This brief frailty index including physical, cognitive, and psychosocial criteria was predictive of increased disability and decreased HRQL at 1 year in older patients with CAD undergoing angiography. This index may have applications for clinicians and researchers but requires further validation.