title: Impaired chronotropic response to exercise stress testing in patients with diabetes predicts future cardiovascular events.
abstract: OBJECTIVE
  To assess the association between impaired chronotropic response (CR) and adverse events among patients with diabetes referred for exercise treadmill testing (ETT).
  
  
  METHODS
  Impaired CR was defined as achievement of <80% of a patient's heart rate reserve. We used multivariable Cox proportional hazards regression to assess the independent association between impaired CR and adverse outcomes adjusting for demographics, comorbidities, and treadmill variables including the Duke Treadmill score.
  
  
  RESULTS
  Of 1,341 patients with diabetes, 35.7% (n = 479) demonstrated impaired CR during ETT. Patients with impaired CR were at increased risk of all-cause mortality, myocardial infarction, or coronary revascularization procedures. In multivariable analyses, impaired CR remained significantly associated with adverse outcomes (hazard ratio 1.53 [95% CI 1.10-2.14]).
  
  
  CONCLUSIONS
  Among patients with diabetes, impaired CR is common during ETT and is associated with adverse outcomes. Impaired CR can be used as another noninvasive tool to risk-stratify patients with diabetes following ETT.
authors.affiliation: 1Denver VA Medical Center, Denver, Colorado, USA. michael.ho@uchsc.edu
authors.forename: P Michael
authors.initials: PM
authors.lastname: Ho
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Maddox
authors.forename: Colleen
authors.initials: C
authors.lastname: Ross
authors.forename: John S
authors.initials: JS
authors.lastname: Rumsfeld
authors.forename: David J
authors.initials: DJ
authors.lastname: Magid
mesh_terms: D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000401:mortality; D003920:Diabetes Mellitus / Q000401:mortality / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000453:epidemiology* / Q000401:mortality; D005080:Exercise Test; D017079:Exercise Tolerance; D006801:Humans; D008487:Medical History Taking; D011237:Predictive Value of Tests; D016019:Survival Analysis; D013997:Time Factors