Objective: We examined race differences in diabetes outcomes over 4-8 years in a single HMO.
Research design and methods: We identified black and white adult diabetic patients who were continuously enrolled (1992-2001) and in whom diabetes was 1) diagnosed before 1994 (n = 1,686) or 2) newly diagnosed in 1994-1997 (n = 1,280). We used hierarchical models to estimate the effect of race on average annual HbA(1c) (A1C) controlling for baseline A1C, BMI, and age, as well as annual measures of type of diabetes medications, diabetes-related hospitalization, time and the number of A1C tests, physician visits, and nondiabetes medications. Stratifying by sex accounted for significant interactions between sex and race.
Results: At baseline, black and white patients had similar rates of A1C testing and physician visits, but blacks had higher unadjusted A1C values. In multivariate models, among patients with previously diagnosed diabetes, average A1C was nonsignificantly 0.11 higher (95% CI -0.12 to 0.34) in black than in white men but was 0.30 higher (0.14-0.46; P = 0.0007) in black than in white women. Among patients with newly diagnosed diabetes, the adjusted black-white gap was 0.49 among men (0.17-0.80; P = 0.007) and was 0.05 among women (-0.20 to -0.31), which was positive but not significant.
Conclusions: Factors other than the quality of care may explain persistent race differences in A1C in this setting. Future interventions should target normalization of A1C by identifying potential psychosocial barriers to therapy intensification among patients and clinicians and development of culturally appropriate interventions to aid patients in successful self-management.