Table 1.

Socioeconomic factors in studies of racial differences in ESRD

Author, YearData Source, PopulationType of SES MeasuresSES MeasuresFindingsLimitations
Whittle et al., 19913Maryland regional ESRD registry, 534 cases of HTN-ESRDarea-based, 13 black and 13 white populations formed by grouped zip codes (20,495 to 420,489 persons)% completing high school; % with household income of at least $10,000
SES was associated with incidence, but did not reduce B:W RR significantlySES measures from very large geographic areas lack of age-gender adjustment ecological analysis (26 populations)
Brancati et al., 19924Maryland regional ESRD registry, 442 cases of DM-ESRD% lacking regular source of health care, insurance, and college education; % with household income ≤$10,000
Byrne et al., 19945New York Medicare program, 9,390 ESRD casesarea-based, zip codemedian family incomeESRD incidence tended to decrease with increasing SES for whites, but not for blackscrude ESRD rates calculated for each of SES levels
Young et al., 19946USRDS, 80,172 ESRD casesarea-based, countyaverage per capita incomeB:W RR was decreasing with increasing income (race-income interaction)SES measures from very large geographic areas
Perneger et al., 19957Maryland, Virginia, West Virginia, 716 cases and 361 controlsindividualhousehold annual income, health insurance, number of missing teethcrude B:W OR was 8.1 and decreased to 5.5 after adjusting for incomelimited generalizability potential for selection bias
Klag et al., 19978MRFIT, 332,544 menarea-based, zip codemedian family incomesimilar ESRD-SES associations were present in both races. B:W RRs were 1.59 (NS), 2.47 (S), and 1.62 (NS) for <15,000, 15,000 to 20,000, and ≥20,000 categorieslimited generalizability assumed median family income was stable over 17 yr
Karter et al., 20029Kaiser Permanente, 62,432 diabeticsindividual; area-based, census blockeducation (individual) average income (census block)age-gender–adjusted estimates of ethnic differences did not differ substantially from those additionally adjusted for SESlimited generalizability (fully insured DM patients)
Tarver-Carr et al., 200210NHANES, 9,082 adults, 37 ESRD casesindividualpoverty status, educational attainment, marital statusage-gender–adjusted B:W RR was 2.7 and was reduced for just 12% after adjusting for SES (RR = 2.5)limited power (only 37 cases)
Li et al., 200411Medicare 5% database, 1,055,236 beneficiariesarea-based, countymedian family incomeage-gender–adjusted B:W RR reduced from 3.5 to 2.9 after adjustment for SES and comorbidities, and to 2.1 in full modelSES contribution to reduced incidence is hard to assess limited generalizability (population 65 and older)
  • MRFIT, Multiple Risk Factors Intervention Trial; HTN, hypertension; DM, diabetes mellitus; NS, not significant; S, statistically significant.