Strong HbA1c from diagnosis prevents complications for 20 years

Research has consistently shown that good control of blood glucose levels reduces the risk of long term complications and now a study from Sweden has showed that when good control is achieved in type 1 diabetes from diagnosis, long term complications can be reliably eliminated for at least 20 years.
The study involved 451 patients with type 1 diabetes that were newly diagnosed between 1983 and 1987. All participants were under 35 years of age when diagnosed. The researchers recorded rates of the microvascular complications, retinopathy (eye disease) and nephropathy (kidney disease), from screening tests and medical records.
Blood glucose control was measured by weighted mean HbA1c levels over the follow up period of 20 to 24 years. Well controlled diabetes was defined as having a long-term weighted mean HbA1c levels below 60 mmol/mol (7.6%) over the 20 plus years of follow up. The researchers compared the well controlled participants with those that had poor diabetes control; that is having a long-term average HbA1c of above 80 mmol/mol (9.5%).
The results showed that none of the participants with well controlled diabetes developed proliferative retinopathy or persistent macroalbuminuria (protein in the urine as a result of kidney disease). By contrast, just over half of those with a long term HbA1c of above 80 mmol/mol (9.5%) developed proliferative retinopathy over the follow up period and nearly a quarter had developed persistent macroalbuminuria.
The study further illustrates the importance of maintaining a strong HbA1c from diagnosis. The results also provide incentive for newly diagnosed patients to aim to consistently achieve an HbA1c below 60 mmol/mol.
Within the UK, the target HbA1c is 48 mmol/mol (6.5%) for people with type 1 diabetes with a wider target of 58 mmol/mol (7.5%) for patients at increased risk of hypoglycemia. Achieving these targets is a reliable way of preventing the complications of diabetes from developing for decades.