title: Incremental prognostic value of SPECT-MPI in chronic kidney disease: A reclassification analysis.
abstract: Traditional cardiovascular (CV) risk factors have limited predictive value of CV mortality in patients with chronic kidney disease (CKD, creatinine clearance less than 60 mL/minute per 1.73 m2). The aim of this study was to evaluate incremental and independent prognostic value of single-photon emission computerized tomography-myocardial perfusion imaging (SPECT-MPI) across continuum of renal function.
  
  
  
  We retrospectively studied 11,518 (mean age, 65 ± 12 years; 52% were men) patients referred for a clinical indication of SPECT-MPI between April 2004 and May 2009. Primary end point was composite of cardiac death and non-fatal myocardial infarction (CD/MI). We examined the relationship of total perfusion defect (TPD) and CD/MI in multiple Cox regression models for CV risk factors and GFR. The incremental predictive value of TPD was examined using Harrell's c-index, net reclassification index (NRI), and integrated discrimination index (IDI).
  
  
  
  Over a median follow-up of 5 years (25th to 75th percentiles, 3.0-6.5 years), 1,692 (14.5%) patients experienced CD/MI (740 MI and 1,182 CD). In a multivariable model adjusted for traditional CV risk factors and GFR, the presence of a perfusion defect was independently associated with increased risk of CD/MI (HR = 2.10; 95% CI 1.81, 2.43, p < .001). Using Cox regression, TPD improved the discriminatory ability beyond traditional CV risk factors and GFR [from AUC = 0.725, (95% CI 0.712-0.738) to 0.784, (95% CI 0.772-0.796), p < .0001]. Furthermore, TPD improves risk stratification of CKD patients over and above traditional CV risk factors and GFR [NRI = 14%, 95% CI (12%-16%, p < .001) and relative IDI = 60%, 95% CI (51%, 66%, p < .001)].
  
  
  
  Across the spectrum of renal function, SPECT-MPI perfusion defects independently and incrementally reclassified patients for their risk of CD/MI, beyond traditional CV risk factors.
authors.affiliation: King Abdulaziz Cardiac Center, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, P.O. Box 22490, Riyadh, 11426, Saudi Arabia.
authors.forename: Amjad M
authors.initials: AM
authors.lastname: Ahmed
authors.affiliation: Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA.
authors.forename: Waqas T
authors.initials: WT
authors.lastname: Qureshi
authors.affiliation: Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA.
authors.forename: Wesley T
authors.initials: WT
authors.lastname: O'Neal
authors.affiliation: Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA.
authors.forename: Fatima
authors.initials: F
authors.lastname: Khalid
authors.affiliation: King Abdulaziz Cardiac Center, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, P.O. Box 22490, Riyadh, 11426, Saudi Arabia. mouaz74@gmail.com.|King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia. mouaz74@gmail.com.|King Abdullah International Medical Research Center, Riyadh, Saudi Arabia. mouaz74@gmail.com.|Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, MI, USA. mouaz74@gmail.com.
authors.forename: Mouaz H
authors.initials: MH
authors.lastname: Al-Mallah
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003643:Death; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000401:mortality*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012307:Risk Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
keywords: SPECT-MPI; cardiovascular death; chronic kidney disease; myocardial infarction; perfusion defects; risk reclassification