Diabetes complications differ according to ethnicity, disease-related subgroups
Risks for diabetes complications vary according to subgroups related to age of onset, HbA1c, obesity and insulin use, and there are racial and ethnic disparities in the composition of each subgroup, according to study data.
“Our findings add to a growing body of research, which show that type 2 diabetes can be categorized into finer disease subgroups that differ in risk for complications,” Mike Bancks, PhD, an assistant professor at Wake Forest School of Medicine, told Healio. “In our study, we included a clinical population of South Asian, non-Hispanic white, Chinese, Hispanic and Black Americans to make this area of research more applicable to a broader audience.”
Bancks and colleagues analyzed pooled data from two U.S. observational epidemiologic studies, the Mediators of Atherosclerosis in South Asians Living in America (MASALA) and the Multi-Ethnic Study of Atherosclerosis (MESA). The MASALA study included South Asian adults aged 40 to 84 years living in the Chicago and San Francisco metropolitan areas. Participants had no cardiovascular disease at their baseline visit from 2010 to 2013. Follow-up visits were conducted from 2015 to 2018. MESA included white, Black, Hispanic and Chinese American adults aged 45 to 84 years without CVD from six metropolitan areas in the U.S. Baseline visits were conducted from 2000 to 2002, and participants were invited to participate in five follow-up visits. Researchers obtained and analyzed data on demographics, medical history, use of medications, health behaviors, blood samples and CT scans.
Ethnic composition of subgroups
There were 1,293 participants (46.4% women) with diabetes in the study, of whom 217 were South Asian, 240 were white, 125 were Chinese American, 387 were Black and 324 were Hispanic. Researchers broke down the cohorts into five subgroups: older age at diabetes onset (n = 554), severe hyperglycemia (n = 340), severe obesity (n = 259), younger age at diabetes onset (n = 19) and insulin use (n = 121). Subgroup assignment differed by ethnicity. The most probable subgroup assignment was older age at diabetes onset except for South Asians, who had severe hyperglycemia as the most likely subgroup.
“The diabetes subgroups were not uniform in racial/ethnic composition,” Bancks said. “We know that experienced racism and structural differences in living situations and health care access impact individuals’ health in both obvious and less subtle ways. These factors may also impact which diabetes subtype an individual will develop. This is concerning because risk for subclinical kidney and heart disease was not uniform across the diabetes subgroups. These findings provide a framework for future research to identify the social determinants of diabetes subgroup membership and to develop more efficient prevention and treatment strategies.”
Complication risks by subgroup, ethnicity
Of the five diabetes subgroups, those with severe hyperglycemia and severe obesity had the highest mean systolic blood pressure. The severe hyperglycemia subgroup had the highest total cholesterol, whereas the severe obesity group had the lowest HDL cholesterol. The severe hyperglycemia group had the highest risk for atherosclerotic CVD, whereas the younger age at diabetes-onset cohort had the lowest risk. The severe hyperglycemia subgroup also had the highest adjusted mean estimated glomerular filtration rate, whereas the insulin use subgroup had the lowest.
There were 176 cases of prevalent chronic kidney disease at baseline. Among ethnic groups, the prevalence for CKD was highest for white participants. After adjusting for ethnicity and clinical risk factors, the insulin use subgroup had the highest probability for prevalent CKD and the severe hyperglycemia subgroup had the lowest. Among those without CKD at baseline, there were 176 cases of CKD at follow-up. Black and Hispanic participants had the highest probability for incident CKD, greater than 20% for both. In adjusted analyses the insulin use subgroup had the highest risk for incident CKD.
There were 782 participants with a coronary artery calcium (CAC) score greater than 0 Agatston units at baseline and 435 with a CAC score greater than 100 Agatston units. When broken down by ethnicity, the probability for prevalent CAC at baseline was lowest for Black participants. In adjusted analyses, the young age at diabetes onset and insulin use groups had the highest probability for prevalent CAC. Among individuals with a CAC score of 0 Agatston units at baseline, there were 127 cases of incident CAC at follow-up. South Asians had the highest probability for incident CAC by ethnicity, and Chinese, Black and Hispanic participants had the lowest. Adjusted analyses showed those in the severe hyperglycemia subgroup had the highest probability for incident CAC, and the younger age at diabetes-onset subgroup had the lowest.
The findings of the study can be used by providers to create individual strategies for those with diabetes, the researchers wrote.
“Health care providers can identify which diabetes subgroup that their patient most closely aligns and the subclinical complications that are most likely for that diabetes subgroup, and then develop strategies with their patient to prevent the clinical events from occurring,” Bancks said.
For more information:
Mike Bancks, PhD, can be reached at firstname.lastname@example.org.