Diabetes is a very diverse condition, which can make studying it difficult in a number of ways. Aside from differences between type 1 and type 2 (and other diabetes types), some people get diabetes at a younger age, while others are older at diagnosis; some people are overweight or obese, while others aren’t; and some people experience wide blood glucose swings that can spike their levels very high, while others don’t experience this. The only thing that people with diabetes have in common, really, is elevated blood glucose levels if their condition isn’t treated.
So it’s surprising, in a sense, that more research hasn’t been done to uncover some of the differences in how people experience diabetes, or at least identify patterns. A new study took on this work, identifying several major patterns in how people experience diabetes. What’s more, the study found that there were large differences between different ethnic groups in how these patterns showed up — suggesting that different populations may experience diabetes in very different ways, in addition to the huge differences seen on an individual level.
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Five diabetes subgroups identified
The study, published in the Journal of Clinical Endocrinology & Metabolism, looked at the combined data from multi-ethnic studies of diabetes that included South Asian, non-Hispanic white, Chinese, African American and Hispanic participants. Researchers looked at many different factors to identify patterns in diabetes — including age at diagnosis, body-mass index (BMI, a measure of weight that takes height into account), A1C (a measure of long-term blood glucose control), insulin resistance and pancreatic beta cell function.
In addition to identifying specific patterns, the researchers wanted to find out if patterns could be seen across different ethnic groups, and also whether certain patterns were associated with cardiovascular disease risk factors and diabetes complications.
The researchers found that participants could be divided into five distinct diabetes subgroups based on major characteristics — an older age at diabetes onset (43% of participants), severe hyperglycemia (high blood glucose; 26%), severe obesity (20%), needing to take insulin (9%), and a younger age at diabetes onset (1%).
There were some notable differences between ethnic groups in how common the five different diabetes subgroups were, as noted in an article at MedPage Today. While the older-onset subgroup was the most common in nearly all of the ethnic groups in the study, this wasn’t the case for South Asians — instead, the severe-hyperglycemia subgroup was the most common. South Asians had the youngest average age of diabetes diagnosis, while the younger-onset subgroup didn’t include any Chinese participants.
The researchers also found differences in how each of the five diabetes subgroups were at risk for certain clinical characteristics and complications. As one would expect, the highest average A1C level was seen in the severe-hyperglycemia subgroup (A1C of 8.3%), followed by the insulin subgroup (7.8%) and the younger-onset subgroup (7.7%). The severe-hyperglycemia subgroup also had the highest average total cholesterol level (193.8 mg/dl), while the severe-obesity subgroup had the lowest average HDL (high-density lipoprotein, or “good”) cholesterol level (43.2 mg/dl).
In a finding that some people might find surprising, the younger-onset subgroup had the lowest average predicted risk for atherosclerosis (plaque buildup in the arteries) over 10 years. The highest predicted risk of developing atherosclerosis was seen in the severe-hyperglycemia subgroup.
When it came to kidney function and the risk of developing diabetic kidney disease, the best kidney function based on estimated glomerular filtration rate (eGFR) was seen in the severe-hyperglycemia subgroup, while the worst kidney function was seen in the insulin subgroup. The insulin subgroup had the highest risk of developing kidney disease based on eGFR and other factors, while the younger-onset subgroup had the lowest risk of developing kidney disease.
The incidence of actual kidney disease was highest in white participants, while Black and Hispanic participants had the highest risk of developing kidney disease based on their eGFR and other factors.
Looking at diabetes subgroups to predict risks
This study highlights the potential benefits of identifying more detailed “types” of diabetes, based on characteristics like age at diabetes onset, insulin use, BMI, and blood glucose control. While these more detailed subgroups may vary across different ethnic groups, ultimately a person’s individual factors determine what subgroup they belong to.
It isn’t clear why certain diabetes-related characteristics seem to be more common in some ethnic groups, especially since these groups “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. But more research into how ethnicity and diabetes subgroups are related may help identify ways to address risks in different groups, including cardiovascular and kidney risks.
What’s more, “Strategies to eliminate racial/ethnic disparities in complications may need to consider approaches targeted to diabetes subgroup,” the researchers wrote. And no matter your race or ethnicity, targeting treatment approaches to your diabetes subgroup could lead to better outcomes, with better blood glucose control and a lower risk of developing complications.
Want to learn more diabetes basics? Read “Diabetes 101.”