— Risk of complications differed among diabetes subgroups
Ethnic differences emerged among subgroups of diabetes characteristics, a new study found.
In an analysis of nearly 1,300 people with diabetes, five distinct types of diabetes cases were identified -- older age at diabetes onset (43%), severe hyperglycemia (26%), severe obesity (20%), younger age at onset (1%), and requiring insulin medication use (9%), reported Michael Bancks, PhD, MPH, of Wake Forest School of Medicine in Winston-Salem, North Carolina, and colleagues.
The distribution of patients within each diabetes subgroup varied vastly according to ethnicity and clinical characteristics, they noted in the Journal of Clinical Endocrinology & Metabolism.
"Prior research on diabetes subgroups has shown that some subgroups have different risks for diabetes complications but has largely been limited to white study populations,"
Bancks explained in a statement. "The topic of diabetes subgroups is an important research question, and our work expanded the study population to include South Asians, non-Hispanic whites, Chinese, Hispanic, and Black people to make this area of research more applicable to a broader population."
Pooling two U.S.-based observational studies of people with diabetes -- the Mediators of Atherosclerosis in South Asians Living in America (MASALA) and the Multi-Ethnic Study of Atherosclerosis (MESA) -- this analysis included survey data on 217 South Asian, 240 non-Hispanic white, 125 Chinese, 387 Black, and 324 Hispanic patients.
Diabetes status was defined as use of an antidiabetic medication, fasting glucose levels ≥126 mg/dL, and HbA1c ≥6.5%. Structured questionnaires were utilized to gather patient data on demographics, medical history, medication, and health-related behaviors like physical activity, smoking, and alcohol consumption.
While the most common subgroup was having an older age at the onset of diabetes -- where nearly half the cohort fell -- this was unlikely to be the case for people of South Asian descent. Instead, South Asians were most likely to fall into the "severe hyperglycemia" subgroup.
People in the severe hyperglycemia subgroup were also less likely to be women.
And while few people across the board fell into the subgroup of being younger at the onset of their diabetes, this category notably didn't have any Chinese patients. Of all ethnicities, South Asian patients had the youngest average age at diabetes diagnosis.
As for body mass index (BMI), Chinese and South Asian patients had the lowest average BMI, while Hispanic people with diabetes had the highest average BMIs.
Beyond demographics, certain clinical factors were more prevalent in specific diabetes subgroups.
Not surprisingly, the severe hyperglycemia group had the highest HbA1c levels (8.3%), followed by those who used insulin (7.8%), and those who were younger at diabetes onset (7.7%).
Looking specifically at cardiovascular-related factors, those in the severe hyperglycemia subgroup had the highest total cholesterol levels (193.8 mg/dL; 5.02 mmol/L). Those in the severe obesity subgroup had the lowest high-density lipoprotein cholesterol levels (43.2 mg/dL; 1.12 mmol/L).
Patients who were a younger age at diabetes onset had the lowest average 10-year predicted risk for atherosclerotic cardiovascular disease; this risk was highest for those in the severe hyperglycemia group.
More than 60% of the total cohort had presence of coronary artery calcium (CAC) at baseline, suggesting plaque buildup, with a third of patients having a CAC score of over 100.
Those with severe hyperglycemia and South Asian patients were determined to be most likely to develop CAC, while Chinese and Hispanic patients had the lowest risk for incident CAC.
Looking at kidney function, patients on insulin had the lowest average estimated glomerular filtration rate (eGFR) of all diabetes subgroups, while those with severe hyperglycemia had the highest average eGFR. The prevalence of chronic kidney disease was most common in white patients at baseline, but Black and Hispanic patients had the highest predicted probability for developing chronic kidney disease in the future.
Over 5-7 years of follow-up, those on insulin were determined to be most likely to develop chronic kidney disease, while those at a younger age at diabetes onset were least likely.
"While our goal was to assess diabetes cluster differences by race and ethnicity, these constructs encompass an array of factors, including ancestry, cultural heritage influencing such aspects as dietary preferences, differences in access and affordability of medical care, migration, and possible influence by racism," the researchers wrote.
"Findings should not be interpreted as attributing different underlying genetic mechanisms to race/ethnicity," they noted.
Journal of Clinical Endocrinology & Metabolism
Source Reference: Bancks MP, et al "Association of diabetes subgroups with race/ethnicity, risk factor burden and complications: the MASALA and MESA studies" J Clin Endocrinol Metab 2021; DOI: 10.1210/clinem/dgaa962.
There are known disparities in diabetes complications by race and ethnicity. Although diabetes subgroups may contribute to differential risk, little is known about how subgroups vary by race/ethnicity.
Data were pooled from 1293 (46% female) participants of the Mediators of Atherosclerosis in South Asians Living in America (MASALA) and the Multi-Ethnic Study of Atherosclerosis (MESA) who had diabetes (determined by diabetes medication use, fasting glucose, and glycated hemoglobin [HbA1c]), including 217 South Asian, 240 non-Hispanic white, 125 Chinese, 387 African American, and 324 Hispanic patients. We applied k-means clustering using data for age at diabetes diagnosis, body mass index, HbA1c, and homeostatic model assessment measures of insulin resistance and beta cell function. We assessed whether diabetes subgroups were associated with race/ethnicity, concurrent cardiovascular disease risk factors, and incident diabetes complications.
Five diabetes subgroups were characterized by older age at diabetes onset (43%), severe hyperglycemia (26%), severe obesity (20%), younger age at onset (1%), and requiring insulin medication use (9%). The most common subgroup assignment was older onset for all race/ethnicities with the exception of South Asians where the severe hyperglycemia subgroup was most likely. Risk for renal complications and subclinical coronary disease differed by diabetes subgroup and, separately, race/ethnicity.
Racial/ethnic differences were present across diabetes subgroups, and diabetes subgroups differed in risk for complications. Strategies to eliminate racial/ethnic disparities in complications may need to consider approaches targeted to diabetes subgroup.
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