Diabetes Complications May Vary Considerably by Race and Ethnicity

The severity of complications from diabetes appear to differ by race and ethnicity, shows research published in the Journal of Clinical Endocrinology and Metabolism. Investigators from Wake Forest School of Medicine in North Carolina report having found considerable variation across racial and ethnic groups, demonstrating the heterogeneity of diabetes.

“In our work, membership in the older age at onset diabetes subgroup was associated with better profiles for most all cardiovascular disease risk factors and 10-year predicted atherosclerotic cardiovascular disease risk despite this group being on average 5 years older than any of the 4 other diabetes subgroups. Membership in the severe obesity subgroup was associated with the worst systolic blood pressure and LDL-cholesterol profiles, but this did not correspond to the highest risk for incident chronic kidney disease or coronary artery calcium,” wrote researcher who were led by Mike Bancks, PhD, MPH, of the Division of Public Health Sciences at Wake Forest.

Using methodology applied in prior studies, researchers sought to characterize potential subgroups of people with diabetes across 5 racial/ethnic groups, then examine the associations and potential complication risks. Data from 2 U.S. community-based, observational, epidemiological studies—MASALA and MESA— were used.

MASALA (Mediators of Atherosclerosis in South Asians Living in America) is a prospective cohort including 906 South Asian adults living in the San Francisco Bay Area, California, and Chicago, Illinois. MESA (Multi-Ethnic Study of Atherosclerosis) is a cohort of 6,814 adults from 4 racial/ethnic groups — non-Hispanic white, African American, Hispanic, and Chinese American — from 6 communities across the United States.

Researchers used structured questionnaires to collect demographic, medical history, and health behavior information. Clinical measurements, including resting seated blood pressure, laboratory evaluation of blood samples, and fasting glucose, were also collected.

The final cohort for this study included 1,293 adults with diabetes from MESA and MASALA: 217 South Asians (, 240 non-Hispanic Whites, 125 Chinese Americans, 387 African Americans, and 324 Hispanic Americans). Patients were allocated to 1 of 5 diabetes subgroup clusters, each of which had at least 1 distinguishing feature (older age at diabetes onset, severe hyperglycemia, severe obesity, young age at diabetes onset, and insulin use in clusters 1 through 5, respectively).

Within each cluster, researchers found differences in patient characteristics based on race. For example, cluster 4 representing young age at diabetes onset, had few patients and did not include any Chinese Americans. Hispanic American participants had a higher mean body mass index compared with other race/ethnic groups within the subgroup, and South Asians had the youngest mean age at diabetes diagnosis across all subgroups.

Investigators also estimated the predicted mean value for cardiovascular disease (CVD) risk factor levels by diabetes cluster, both before and after adjustment for confounders. Participants in the severe obesity and severe hyperglycemia subgroups had the highest adjusted total cholesterol levels, while those in the severe obesity subgroup had the lowest adjusted levels of high-density lipoprotein cholesterol.

At baseline, there were 176 prevalent cases of chronic kidney disease. Unadjusted point prevalence ranged from 3% to 19% in the severe hyperglycemia and older onset subgroups. Coronary artery calcium (CAC) was also evaluated; 782 participants had CAC >0, and 435 had CAC >100. After adjustment, CAC predicted probability was highest for the younger age at onset and insulin use subgroups.

Several study limitations were noted, including the inclusion of people with prevalent diabetes and longer diabetes duration in the final cohort, which may have influenced cluster characteristics and an inability to include data on autoantibodies. The investigators also noted that although the study sample was older and more racially diverse, the findings “should not be interpreted as attributing different underlying genetic mechanisms to race/ethnicity.”

“Racial/ethnic differences were present across diabetes subgroups [which] differed in risk for complications,” the researchers concluded. “Strategies to eliminate racial/ethnic disparities in complications may need to consider approaches targeted to diabetes subgroup.”

Reference

Bancks MP, Bertoni AG, Carnethon M, et al. Associations of diabetes subgroups with race/ethnicity, risk factor burden and complications: The MASALA and MESA studies. Published online January 27, 2021. J Clin Endocrinol Metab. doi: 10.1210/clinem/dgaa962