title: Quadriceps Strength as a Predictor of Mortality in Coronary Artery Disease.
abstract: BACKGROUND
  The purpose of this study was to investigate the prognostic value of quadriceps isometric strength (QIS) in coronary artery disease (CAD).
  
  
  METHODS
  The study population consisted of 1314 patients aged >30 years (64.7 ± 10.6 years, 1051 male) with CAD who were hospitalized for acute coronary syndrome or coronary artery bypass grafting. Maximal QIS was evaluated as a marker of leg strength and expressed relative to body weight (% body weight). The primary and secondary endpoints were all-cause death and cardiovascular (CV) death, respectively.
  
  
  RESULTS
  During a mean follow-up of 5.0 ± 3.5 years, corresponding to 6537 person-years, there were 118 all-cause deaths and 63 CV deaths. A higher QIS remained associated with decreased all-cause mortality and CV mortality risks (hazard ratio for increasing 10% body weight of QIS 0.77, 95% confidence interval 0.67-0.89, P < .001 for all-cause death; hazard ratio 0.66, 95% confidence interval 0.54-0.82, P < .001 for CV death) after adjustment for other prognostic factors. The inclusion of QIS significantly increased both continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI) for all-cause death (cNRI: 0.25, P = .009; IDI: 0.007, P = .030) and CV death (cNRI: 0.34, P = .008; IDI: 0.013, P = .008).
  
  
  CONCLUSIONS
  A high level of quadriceps strength was strongly associated with a lower risk of both all-cause and CV mortality in patients with CAD. Evaluation of QIS offered incremental prognostic information beyond pre-existing risk factors.
authors.affiliation: Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan. Electronic address: k-kamiya@kitasato-u.ac.jp.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kamiya
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Masuda
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan; Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Hamazaki
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Matsue
authors.affiliation: Exercise Pathophysiology Laboratory, Cardiac Rehabilitation Division, Salvatore Maugeri Foundation IRCCS, Scientific Institute of Veruno, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mezzani
authors.affiliation: Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Matsuzawa
authors.affiliation: Department of Rehabilitation, Kitasato University Hospital, Sagamihara, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Nozaki
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Maekawa
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Noda
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Yamaoka-Tojo
authors.affiliation: Department of Health Information Management, Kitasato University Hospital, Sagamihara, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan; Department of Rehabilitation, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Matsunaga
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Izumi
authors.affiliation: Department of Cardiovascular Medicine, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Ako
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000401:mortality* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D011379:Prognosis; D052097:Quadriceps Muscle / Q000502:physiology*; D018570:Risk Assessment
keywords: Coronary artery disease; Muscle strength; Prognosis