Anaemia, blood disorders can distort diabetes test HbA1c results, says study

Anaemia, blood disorders can distort diabetes test HbA1c results, says study

Glycated haemoglobin (HbA1c), which is commonly used to diagnose and monitor Type 2 diabetes (T2D), may mislead diagnosis and monitoring in South Asia, particularly in India’s population, due to the high prevalence of anaemia, haemoglobinopathies such as sickle cell disease and thalassaemia, and glucose-6-phosphate dehydrogenase (G6PD) deficiency, says an article published online in Lancet Regional Health: Southeast Asia.

Led by Anoop Misra, corresponding author and chairman of Fortis C-DOC Centre of Excellence for Diabetes, the review questions reliance on HbA1c as the sole diagnostic or monitoring tool for type 2 diabetes in South Asia.

The article adds that poorly standardised HbA1c assay methods complicate interpretation of HbA1c values. “Overall, reliance solely on HbA1c is constrained by several clinical and biological factors in India. A multiparametric, risk-stratified approach that integrates oral glucose tolerance test, self-monitoring of blood glucose, and whenever possible, continuous glucose monitoring, in addition to relevant haematologic assessments, are essential to enhance diagnostic and monitoring accuracy and inform appropriate treatment decisions, especially in primary care and resource-limited settings,’’ Dr. Misra says.

Any condition that affects the quantity, structure, or lifespan of haemoglobin — such as anaemia, haemoglobinopathies, or other red blood cell disorders — can distort HbA1c values and lead to misleading estimates of average blood glucose, the viewpoint article notes.

Co-author Shashank Joshi, from Joshi Clinic, Mumbai, explains that in some regions of India, people are nutritionally challenged and have iron-deficiency anaemia, which can distort HbA1c readings.

“This would affect both diagnosis and monitoring thus misleading clinicians. Reliance on HbA1c alone could delay diagnosis by up to four years in men with undetected G6PD deficiency, potentially increasing risk of complications,’’ Dr. Joshi says.

The article explains that in patients with Type 1 diabetes, a non-linear relationship between mean blood glucose and HbA1c has been documented.