Role of race/ethnicity in diabetes disease burden: A study of hospital discharge data in Chicago

The prevalence of diabetes is reaching epidemic proportions in the U.S., particularly for minorities. To investigate this phenomenon further, we analyzed diabetes discharges rates for Chicago, a heavily segregated city, by race/ethnicity (R/E). A three-year average age-adjusted diabetes discharge rate (AADDR) was calculated for both principal and any diagnosis of diabetes for 2008-2010 for 52 Chicago zip codes and the entire city. For principal diagnosis at the city level, Non-Hispanic Blacks (NHB) had the highest AADDR at 426.0 per 100,000 population. Non-Hispanic Whites (NHW) had the lowest AADDR at 120.6, yielding an NHB:NHW rate ratio (RR) of 3.53. The AADDR for Hispanics (263.0) was comparable to Chicago's rate (288.9). Similar trends were seen for any diagnosis of diabetes, although R/E differences were smaller, with a NHB:NHW RR of 2.15. This lower RR may be attributable to variations in access to and use of health care among R/E groups. Nevertheless, both RRs are higher than the national RR of 1.77, demonstrating that national estimates are inadequate for understanding local disparities. For principal diagnosis at the zip code level, AADDR ranged from 38.0 to 626.6 per 100,000 population. AADDR was positively correlated with % Black (r=0.84, p<.0001) and negatively correlated with median household income (r=-0.71, p<.0001). The relationship between AADDR and income remained significant for predominantly white (>60%) zip codes, but lost significance for predominantly black zip codes. These results suggest the role of R/E may be more influential than income and location in determining diabetes disease burden in Chicago.