Response to Letter Regarding Article, “Association of Race With Mortality and Cardiovascular Events in a Large Cohort of US Veterans”

Epidemiology and Prevention Association of Race With Mortality and Cardiovascular Events in a Large Cohort of US Veterans Csaba P. Kovesdy, MD; Keith C. Norris, MD, PhD; L. Ebony Boulware, MD, MPH; Jun L. Lu, MD; Jennie Z. Ma, PhD; Elani Streja, PhD, MPH; Miklos Z. Molnar, MD, PhD; Kamyar Kalantar-Zadeh, MD, PhD, MPH Background—In the general population, blacks experience higher mortality than their white peers, attributed in part to their lower socioeconomic status, reduced access to care, and possibly intrinsic biological factors. Patients with kidney disease are a notable exception, among whom blacks experience lower mortality. It is unclear if similar differences affecting outcomes exist in patients with no kidney disease but with equal or similar access to health care. Methods and Results—We compared all-cause mortality, incident coronary heart disease, and incident ischemic stroke using multivariable-adjusted Cox models in a nationwide cohort of 547 441 black and 2 525 525 white patients with baseline estimated glomerular filtration rate ≥60 mL·min −1 ·1.73 m −2 receiving care from the US Veterans Health Administration. In parallel analyses, we compared outcomes in black versus white individuals in the National Health and Nutrition Examination Survey (NHANES) 1999 to 2004. After multivariable adjustments in veterans, black race was associated with 24% lower all-cause mortality (adjusted hazard ratio, 0.76; 95% confidence interval, 0.75–0.77; P 41 million individuals. 1 Poorer health outcomes in blacks have been well docu- mented. 2–6 These outcome differences have been ascribed largely to the substantial socioeconomic disadvantage of blacks, with resultant lower health literacy, decreased dis- ease awareness, suboptimal access to health care, and overt or latent discrimination in receiving recommended health- care interventions. 7 outcomes of blacks are likely even more complex and are affected by genetic differences between individuals of African and European ancestry. 8 A notable example for this is the advanced stages of chronic kidney disease (CKD) and end- stage renal disease (ESRD), the incidence and prevalence of which are disproportionately higher in blacks, in part as a result of recently described common genetic polymorphisms in individuals of African ancestry, 9–13 but paradoxically, blacks with advanced CKD and ESRD have lower mortality than their white peers. 14,15 The markedly different pathogenesis of CKD in blacks could affect race-associated clinical outcomes in patients with kidney disease (eg, by affecting differently the age and comorbidity characteristics of affected patients). It is possible that there are also other CKD-independent Editorial see p 1519 Clinical Perspective on p 1548 Notwithstanding the validity and importance of these factors, the underlying causes for differences in the health Received December 25, 2014; accepted August 10, 2015. From Nephrology Section, Memphis VA Medical Center, TN (C.P.K.); Division of Nephrology, University of Tennessee Health Science Center, Memphis (C.P.K., J.L.L., M.Z.M.); Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA (K.C.N.); Department of Medicine, Duke University, Durham, NC (L.E.B.); Department of Public Health Sciences and Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville (J.Z.M.); and Harold Simmons Center for Chronic Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California–Irvine, Orange (E.S., K.K.-Z.). The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA. 114.015124/-/DC1. Correspondence to Csaba P. Kovesdy, MD, Division of Nephrology, Memphis VA Medical Center, 1030 Jefferson Ave, Memphis, TN 38104. E-mail ckovesdy@uthsc.edu © 2015 American Heart Association, Inc. Circulation is available at http://circ.ahajournals.org DOI: 10.1161/CIRCULATIONAHA.114.015124