Incremental prognostic value of SPECT-MPI in chronic kidney disease: A reclassification analysis

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 2004 and 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.