Takeshi Nakamura1, Kentaro Kamiya2, Nobuaki Hamazaki3, Ryota Matsuzawa4, Kohei Nozaki3, Takafumi Ichikawa3, Masashi Yamashita5, Emi Maekawa6, Jennifer L Reed7, Chiharu Noda6, Kentaro Meguro6, Minako Yamaoka-Tojo8, Atsuhiko Matsunaga8, Junya Ako6. 1. Department of Rehabilitation Sciences, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, Juntendo University Hospital, Tokyo, Japan. 2. Department of Rehabilitation Sciences, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan. Electronic address: k-kamiya@kitasato-u.ac.jp. 3. Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan. 4. Department of Physical Therapy, School of Rehabilitation, Hyogo University of Health Sciences, Kobe, Japan. 5. Department of Rehabilitation Sciences, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan. 6. Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan. 7. Exercise Physiology and Cardiovascular Health Lab, Division of Cardiac Prevention and Rehabilitation, University of Ottawa Heart Institute, Ottawa, Ontario, Canada; School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada. 8. Department of Rehabilitation Sciences, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan.
Abstract
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.
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 patientsdied. 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.