Background: This study was performed to test the hypothesis that low quadriceps isometric strength (QIS) is associated with greater risk of mortality and has the additive prognostic significance to the severity of heart failure (HF) and gait speed in older patients with HF.
Methods: A retrospective cohort study was performed in 1273 patients ≥ 60 years of age with HF (mean age 75 ± 8 years, 59.1% men); all of whom were evaluated during hospitalization for usual gait speed and maximal QIS. The QIS was expressed relative to body mass (% BM). The endpoint was all-cause mortality.
Results: Over a median follow-up period of 1.59 years (interquartile range, 0.58 to 3.42 years), 224 patients died. The cutoff value based on the Youden index for the QIS discriminating those at high risk of mortality was 36.2% BM for overall, and we defined less than this cutoff point of QIS as low QIS. After adjustment for the HF risk score, the hazard ratio in low QIS was 1.55 for overall (95% confidence interval [CI], 1.17-2.06). The addition of low QIS to the HF risk score and gait speed was associated with significant increases in both net reclassification improvement (NRI, 0.239 for overall; 95% CI, 0.096-0.381) and integrated discrimination improvement (IDI, 0.004 for overall; 95% CI, 0.001-0.009) for all-cause mortality.
Conclusion: Low QIS was strongly associated with poor prognosis and showed complementary prognostic predictive capability to the HF risk score and gait speed in older patients with HF.
Copyright © 2020 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.