According to a study, thousands of South Asian persons in the United Kingdom may receive erroneous type 2 diabetes tests.

Diabetes UK, research type 2 diabetes.
New research, which will be discussed tomorrow at the Diabetes UK Professional Conference 2024, has uncovered a genetic variation that is almost unique to people of South Asian descent and impacts the accuracy of the diabetes haemoglobin A1c (HbA1c) test.

This test measures the average blood sugar level during the past two to three months. It is critical for diagnosing type 2 diabetes, tracking prediabetes, and determining diabetic management.

South Asians with this genetic variation may have artificially low HbA1c values, delaying the diagnosis of type 2 diabetes.

Dr Miriam Samuel of Queen Mary University London and colleagues in the Genes & Health Research Team identified a genetic variant that is found in 7.6 percent of people of South Asian heritage but is rare in other ethnicities using genetic and health data from the Genes & Health study (over 60,000 individuals of Bangladeshi or Pakistani ethnicity living in England) and the UK Biobank (500,000 people of various ethnicity living in the UK).

Individuals with this variation had erroneously reduced HbA1c values and changes in their total blood count.

HbA1c tests determine average blood sugar levels by detecting the amount of sugar bound to haemoglobin in red blood cells.

According to the research, the genetic mutation is connected to alterations in red blood cells, which impacts HbA1c test results.

For persons who have two copies of the genetic variation (homozygous), HbA1c test results may be incorrectly lower by roughly 6 mmol/mol.

The research team examined the health records of South Asians who carried this genetic variant and discovered that those with one copy (heterozygous) were diagnosed with type 2 diabetes one year later, while those with two copies (homozygous) were diagnosed two years later than those without the genetic variant.

Inaccurate HbA1c values may also indicate that persons with the variation are not receiving early and suitable medications to manage blood sugar levels and lower the risk of long-term consequences, such as heart attacks, strokes, amputations, and vision loss.

In England, it is estimated that over 420,000 persons of South Asian descent have diabetes, and over 230,000 have prediabetes, putting them at high risk of developing type 2.

With approximately 7.6% of South Asians harbouring this variation, it appears that the HbA1c test is underestimating blood sugar levels in approximately 32,000 South Asian persons with diabetes and 17,500 with prediabetes in England alone. Thousands of prediabetes cases in South Asians could have also been overlooked.

The findings suggest that South Asians with the variation may require additional blood sugar testing, such as fasting glucose and oral glucose tolerance tests, as well as alternate monitoring channels.

The researchers emphasise the importance of ethnic diversity in genetic research and recommend that more research be conducted to determine whether inaccurate HbA1c results contribute to the diabetes inequalities experienced by South Asians living in the UK, which include an increased risk of developing type 2 diabetes and serious diabetes complications.

Dr. Miriam Samuel of Queen Mary University London stated that many genetic variations associated with red blood cell problems are quite rare among Northern Europeans, who have previously dominated genetic investigations.

"We demonstrate one such variant that is carried by 7.6 per cent of South Asians which could affect the accuracy of HbA1c and cause delays in diabetes diagnosis."

She went on to say: "Studies such as Genes & Health, focussing on populations who are underserved in genetic research, are vital to understand the different pathways that may contribute to diabetes inequalities in these communities."

Dr. Elizabeth Robertson, Director of Research at Diabetes UK, stated, "This evidence indicating that the accuracy of a common test to diagnose and monitor type 2 diabetes is related to a person's ethnicity should be investigated further."

"It's critical that healthcare practitioners have an accurate method for assessing average blood sugar levels throughout time.

"Without this, they are navigating in the dark and may ignore cases of type 2 diabetes.

"Every individual at risk or with diabetes, regardless of their background, deserves equal access to effective diabetes care to live a healthy life and mitigate long-term diabetes complications."