Disparities in undiagnosed diabetes among United States-Mexico border populations.

OBJECTIVE To compare the prevalence of undiagnosed diabetes among populations with diabetes living on the United States (U.S.)-Mexico border, examine explanations for differences between groups, and investigate differences in metabolic outcomes by diagnosis status. METHODS Data come from the U.S.-Mexico Border Diabetes Prevention and Control Project survey (2001-2002), which used a stratified, multistage design. The sample included 603 adults (18 years or older) with diabetes. Undiagnosed diabetes was defined as a fasting plasma glucose (FPG) value of ≥ 126 mg/dL and no report of diagnosis. Logistic regression was used to compare the odds of being undiagnosed among border populations with diabetes. Metabolic outcomes included FPG, glycosylated hemoglobin, and mean arterial blood pressure. RESULTS One in four adults with diabetes (25.9%) living on the U.S.-Mexico border was undiagnosed. Mexicans (43.8%) and Mexican immigrants (39.0%) with diabetes were significantly more likely to be undiagnosed than were U.S.-born Hispanics (15.0%; P < 0.05 for either comparison) or non-Hispanic whites (6.6%; P < 0.001 for either comparison). Mexicans were more likely to be undiagnosed than were all U.S. adults (14.7%; P < 0.001) with diabetes. Significant differences in the likelihood of being undiagnosed remained between all groups with diabetes after adjustment for sociodemographic and healthcare-related covariates, with the exception of that between Mexicans and U.S.-born Hispanics. Worse metabolic control and potentially greater benefits of diagnosis for control were observed for Mexicans in particular compared with U.S. groups with undiagnosed diabetes. CONCLUSIONS Efforts to improve diabetes diagnosis should concentrate on Mexican and Mexican immigrant populations on the U.S.-Mexico border.