Haemorheology and diabetes – what clinical viscosity could tell us

Diabetes is an endocrine disorder characterised by high blood sugar levels. Diabetes is a chronic disease that occurs either when the pancreas produces insufficient insulin or when the body cannot effectively use the insulin it produces.¹ The International Diabetes Federation (IDF, 2021) diabetes atlas reports that, 537 million (10.5%) of the adult population (aged 20-79) has diabetes. IDF projection show that 1 in 8 adults, approximately 783 million, will be living with diabetes by 2045.²

Diabetes mellitus³ was named in 1675 by Thomas Willis, though the symptoms were described as far back as the ancient Egyptians. The name derives from diabetes meaning ‘pass through’ and mellitus meaning ‘sweet’ at a time when the diagnosis was made by tasting the urine of diabetic patients for sweetness. It currently represents one of the largest patient populations and can be broadly classified as two types:⁴ type 1 where the pancreas secretes insufficient insulin due to the body’s immune system attacks and destroy the cells that produce insulin, and type 2 where a resistance to insulin occurs. Further subtypes, up to six categories, exist such as gestational, maturity onset, ketosis prone and hybrid.

Diagnosis and monitoring have seen significant landmarks since it was first described. Arguably the most significant of recent times was the discovery of HbA1c in the early 1970s; the author being one of the first in the UK to measure it and provide a monitoring service in 1979 in Sheffield. Commercial companies further developed the technique, and a comparison was made of the methods available at the time.⁵ HbA1c⁶ reflects the mean blood glucose over the preceding approximate 120 days and by maintaining the level within reference limits is thought to reduce the likelihood of the long-term clinical consequences of poor control by avoiding spikes in blood glucose.