Background/Purpose: Patients with SLE and lupus nephritis (LN) are at elevated risks of cardiovascular disease. Past studies have suggested that African American patients with SLE may be at higher cardiovascular risk than White patients. A large recent study of individuals with end-stage renal disease (ESRD) of any cause showed effect modification of the race-mortality association by age and demonstrated increased mortality among young African American compared to White patients. However, there is little information about mortality and cardiovascular risks among patients with ESRD due to LN, differentiated by race and ethnicity. We tested for differences in mortality and cardiovascular event rates in patients with ESRD due to LN, by race and ethnic group.  

Methods:  Individuals age ≥18 years with incident LN ESRD (ICD-9 code 710.0) between 1995 and 2008 were identified in the US Renal Data System (URDS). Covariates at baseline were ascertained from the Medical Evidence Report (a standardized form including sociodemographics, clinic data and laboratory measures collected at dialysis initiation).  LN was consider as primary cause of renal failure according to the attending nephrologist. Multiple imputation was used for missing baseline data [albumin, body mass index and estimated glomerular filtration rate (eGFR)]. The hazard ratios (HR) for mortality and cardiovascular events (myocardial infarction, heart failure, hemorrhagic and ischemic stroke) during follow-up through December 31, 2008 were estimated using multivariable-adjusted Cox regression

Results: We identified 12,533 patients with ESRD due to LN. Mean age at ESRD onset was 40.7 ± 14.9 years; 81.6% were women and 49% were African American. The total number of deaths, cardiovascular events and their incident rates are shown in Table. Compared to Whites, African Americans had higher risk of death (1.30 [95%CI 1.21-1.39]) and heart failure (1.35 [95%CI 1.24-1.47]). Conversely, Asian patients had lower risk of mortality 0.68 [95%CI 0.65-0.92] and heart failure (0.67[0.50-0.90]). Hispanic patients had lower rates of mortality (0.74 [95%CI 0.66-0.82]), heart failure (0.82 ;95%CI 0.71-0.97), myocardial infarction (0.69 ;95%CI 0.49-0.98), and ischemic stroke (0.68; 95%CI 0.48-0.85) than non-Hispanics.

Table. Hazard Ratios for Mortality and Cardiovascular Events in 12.533 patients with ESRD due to Lupus Nephritis, US patients 1995-2008
	Mortality Total events= 4789	Heart Failure Total events=2276	Myocardial Infarction Total events =464	Ischemic Stroke Total events =456	Hemorrhagic Stroke Total events = 162
	Fully- Adjusted HR	Fully- Adjusted HR	Fully- Adjusted HR	Fully- Adjusted HR	Fully- Adjusted HR
Race
White	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)
Asian	0.68 (0.65-0.92)	0.67 (0.50-0.90)	0.88 (0.50-1.56)	0.62 (0.33-1.16)	1.95 (0.93-4.11)
African American	1.30 (1.21-1.39)	1.23 (1.07-1.41)	0.97 (0.77-1.23)	0.85 (0.67-1.07)	1.09 (0.71-1.65)
Native	1.17 (0.86-1.58)	1.20(0.81-1.78)	0.57 (0.18-1.8)	0.51 (0.16-1.60)	2.05 (0.72-5.83)
Ethnicity
Non-Hispanic	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)	1.0 (Ref)
Hispanic	0.74 (0.66-0.82)	0.83 (0.71-0.97)	0.69 (0.49-0.98)	0.68 (0.48-0.85)	0.81 (0.46-1.45)
IR: Incidence rate
*Multivariable model adjusted for sex, age at ESRD onset ,sex,, calendar year of ESRD onset, race, Hispanic ethnicity,  smoking,  comorbidities  (hypertension, diabetes, coronary artery disease, chronic heart failure, cerebrovascular disease, peripheral vascular disease, cancer, chronic obstructive pulmonary disease), body mass index, albumin, eGFR, employment status, Medicare A+B, and region of residence (Northeast, South, Midwest or West US).)

Conclusion:  Race and ethnicity are associated with mortality and cardiovascular outcomes among LN ESRD patients. While African American patients had significantly higher rates of death and heart failure than Whites, Asian and Hispanic patients had lower rates of these outcomes. The causes of these disparities are not understood, but are likely multifactorial, including genetic, socioeconomic, and environmental factors. Moreover, lower than expected mortality among Hispanic patients has been observed in other studies as well and may be due to people returning to their native countries for end of life care (Borrell LN, Am J Public Health, 2012).

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/associations-of-race-and-ethnicity-with-overall-mortality-and-cardiovascular-events-among-patients-with-end-stage-renal-disease-due-to-lupus-nephritis/