Diabetes Complications at Presentation and One Year by Glycated Haemoglobin at Diagnosis in a Multiethnic and Diverse Socioeconomic Population: Results from the South London Diabetes Study

Abstract EN

Background.

WHO’s recommendation of HbA 1c ≥ 48 mmol/mol (6.5%) as diagnostic for type 2 diabetes mellitus (T2DM) was adopted by three UK London boroughs in May 2012.

The South London Diabetes (SOUL-D) study has recruited people with newly diagnosed T2DM since 2008.

We compared participants diagnosed before May 2012 with HbA 1c < 48 mmol/mol to those with diagnostic HbA 1c ≥ 48 mmol/mol.

Methods.

A prospective cohort study of newly diagnosed T2DM participants from 96 primary care practices, comparing demographic and biomedical variables between those with diagnostic HbA 1c < 48 mmol/mol or HbA 1c ≥ 48 mmol/mol at recruitment and after one year.

Results.

Of 1488 participants, 22.8% had diagnostic HbA 1c < 48 mmol/mol.

They were older and more likely to be white ( p < 0.05 ).

At recruitment and one year, there were no between-group differences in the prevalence of diabetic complications, except that those diagnosed with HbA 1c < 48 mmol/mol had more sensory neuropathy at recruitment ( p = 0.039 ) and, at one year, had new myocardial infarction ( p = 0.012 ) but less microalbuminuria ( p = 0.012 ).

Conclusions.

Use of HbA 1c ≥ 48 mmol/mol as the sole T2DM diagnostic criterion may miss almost a quarter of those previously diagnosed in South London yet HbA 1c < 48 mmol/mol may not exclude clinically important diabetes.