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. J Am Geriatr Soc 58: 1526-1531, 2010.