Poverty, race, and CKD in a racially and socioeconomically diverse urban population

Abstract

Background: Low socioeconomic status (SES) and African American race are both independently associated with end-stage renal disease and progressive chronic kidney disease (CKD). However, despite their frequent co-occurrence, the effect of low SES independent of race has not been well studied in CKD.

Study design: Cross-sectional study.

Setting & participants: 2,375 community-dwelling adults aged 30-64 years residing within 12 neighborhoods selected for both socioeconomic and racial diversity in Baltimore City, MD.

Predictors: Low SES (self-reported household income <125% of 2004 Department of Health and Human Services guideline), higher SES (> or =125% of guideline); white and African American race.

Outcomes & measurements: CKD defined as estimated glomerular filtration rate <60 mL/min/1.73 m(2). Logistic regression used to calculate ORs for relationship between poverty and CKD, stratified by race.

Results: Of 2,375 participants, 955 were white (347 low SES and 608 higher SES) and 1,420 were African American (713 low SES and 707 higher SES). 146 (6.2%) participants had CKD. Overall, race was not associated with CKD (OR, 1.05; 95% CI, 0.57-1.96); however, African Americans had a much greater odds of advanced CKD (estimated glomerular filtration rate <30 mL/min/1.73 m(2)). Low SES was independently associated with 59% greater odds of CKD after adjustment for demographics, insurance status, and comorbid disease (OR, 1.59; 95% CI, 1.27-1.99). However, stratified by race, low SES was associated with CKD in African Americans (OR, 1.91; 95% CI, 1.54-2.38), but not whites (OR, 0.95; 95% CI, 0.58-1.55; P for interaction = 0.003).

Limitations: Cross-sectional design; findings may not be generalizable to non-urban populations.

Conclusions: Low SES has a profound relationship with CKD in African Americans, but not whites, in an urban population of adults, and its role in the racial disparities seen in CKD is worthy of further investigation.

Figure1

Prevalence of CKD (chronic kidney disease) by Socioeconomic Status (SES) and Race. SES is defined as low SES or higher SES based on whether a participant reported annual household income below or above 125% of the 2004 Department of Health and Human Services poverty guideline. CKD Stages were defined by National Kidney Foundation guidelines (Stage 3: 30 ≤ eGFR < 60 mL/min/1.73 m2 , Stage 4: 15 ≤ eGFR < 30 mL/min/1.73 m2 , Stage 5: eGFR < 15 mL/min/1.73 m2). Conversion factor for CKD in mL/min/1.73 m2 to mL/s/1.73 m2, x0.01667.