Mortality Among Low-Income African Americans and Whites With Diabetes

OBJECTIVE

To estimate mortality rates and risk factors for mortality in a low-socioeconomic status (SES) population of African Americans and whites with diabetes.

RESEARCH DESIGN AND METHODS

We determined mortality among African Americans and whites aged 40–79 years with (n = 12,498) and without (n = 49,914) diabetes at entry into a cohort of participants recruited from government-funded community health centers. Multivariable Cox analysis was used to estimate mortality hazard ratios (HRs) (95% CI) among those with versus those without diabetes and among those with diabetes according to patient characteristics.

RESULTS

During follow-up (mean 5.9 years), 13.5% of those with and 7.3% of those without diabetes died. All-cause mortality risk was higher among those with versus without diabetes for both African Americans (HR 1.84 [95% CI 1.71–1.99]) and whites (1.80 [1.58–2.04]), although among those with diabetes, mortality was lower among African Americans than whites (0.78 [0.69–0.87]). Mortality risk increased with duration of diabetes and was greater among patients on insulin therapy and reporting histories of cardiovascular disease (CVD), hypertension, and stroke. The HRs associated with these multiple risk factors tended to be similar by sex and race, with the exception of a differentially higher impact of prevalent CVD on mortality among African Americans (interaction P value = 0.03), despite a lower baseline prevalence of CVD.

CONCLUSIONS

In this population with similarly low SES and access to health care, strong and generally similar predictors of mortality were identified for African Americans and whites with diabetes, with African Americans at a moderately but significantly lower mortality risk.Population studies have consistently shown increased all-cause mortality among individuals with type 2 diabetes (1–4). Several reports have also shown that the impact of diabetes on mortality varies by socioeconomic status (SES) (5–7), race (8–10), and/or sex (4,11). However, scant literature exists on the mortality experience of diabetic patients within low-SES populations in the U.S. and whether within these vulnerable populations mortality varies by sex or race. We have previously reported that the prevalence of diabetes is only slightly higher among African Americans than whites once SES and other risk factors are accounted for (12). We now describe mortality patterns and risk factors for mortality by sex and race in a large, low-SES population of southern U.S. African Americans and whites with type 2 diabetes.