Prognosis in proliferative lupus nephritis: the role of socio-economic status and race/ethnicity

• Published in: Nephrology, dialysis, transplantation Vol. 18; no. 10; pp. 2039 - 2046
• Main Authors: Barr, R. Graham, Seliger, Stephen, Appel, Gerald B., Zuniga, Ricardo, D’Agati, Vivette, Salmon, Jane, Radhakrishnan, Jai
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.10.2003
• Subjects: Adolescent; Adult; African Americans - statistics & numerical data; Age Distribution; Biological and medical sciences; Biopsy, Needle; Cohort Studies; Confidence Intervals; Dermatology; European Continental Ancestry Group - statistics & numerical data; Female; Hispanic Americans - statistics & numerical data; Humans; Incidence; Kidneys; Lupus Nephritis - epidemiology; Lupus Nephritis - pathology; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; poverty; Probability; Prognosis; proliferative lupus nephritis; Proportional Hazards Models; race/ethnicity; Retrospective Studies; Risk Factors; Severity of Illness Index; Sex Distribution; Skin involvement in other diseases. Miscellaneous. General aspects; socio-economic status; Socioeconomic Factors; Survival Rate; systemic lupus erythematosus; United States - epidemiology; Urinary system involvement in other diseases. Miscellaneous; United States; Kidney disease; Human; Immunopathology; Connective tissue disease; Skin disease; Urinary system disease; Poverty; Prognosis; Socioeconomic status; proliferative lupus nephritis; Autoimmune disease; Ethnic group; race/ethnicity; systemic lupus erythematosus; Nephropathy; socio-economic status; Systemic disease; Lupus erythematosus
• ISSN: 0931-0509; 1460-2385; 1460-2385
• DOI: 10.1093/ndt/gfg345

Background. Studies of proliferative lupus nephritis (PLN) suggest that African-Americans have a poorer prognosis than Whites. However, no study has simultaneously examined socio-economic status. We studied rates of progression of PLN among a tri-ethnic population with respect to socio-economic status and race/ethnicity. Methods. A retrospective cohort study was carried out using individual and census-based neighbourhood data. Consecutive patients in urban tertiary care centres with biopsy-proven PLN were studied. The main outcome was time to doubling of serum creatinine. Results. Among 128 patients with PLN, the percentage of patients who did not double their serum creatinine at 5 years was 67.0% (±4.8%) and at 10 years was 58.9% (±5.7%). In bivariate analyses, residence in a poor neighbourhood was positively associated with progression (P = 0.03), as was African-American and Hispanic race/ethnicity (P = 0.01). Residence in a poor neighbourhood remained associated with progression of disease after adjustment for age, sex, creatinine, hypertension, cyclophosphamide treatment and race/ethnicity [relative risk (RR) 3.5, 95% confidence interval (CI) 1.2–11, P = 0.03]. After adjustment for poverty and insurance, the RR for African-American race/ethnicity was reduced from 3.5 to 2.7 and was not statistically associated with progression of disease in the full model (P = 0.10). A similar reduction in RR from 5.5 to 3.6 was seen for Hispanic race/ethnicity, but this retained statistical significance (P = 0.03). Conclusions. Poverty is an important risk factor for progression of PLN, independent of race/ethnicity. Hispanics have an elevated risk similar to or greater than African-Americans. Given these findings, some of the poorer prognosis of African-American patients with PLN may result from socio-economic rather than biological or genetic factors.