Diagnosing diabetes: a new paradigm

Abstract

Diabetes mellitus is an important international health concern due to its increasing prevalence and high associated social and economic costs. In the UK, over 2.7 million people have diabetes, predicted to rise to 4 million people by 2025.1 Approximately 10–15% of the hospital inpatients are affected by diabetes, and ∼10% of healthcare spending is directly related to diabetes and its attendant complications. Diabetes contributes significantly to mortality from cardiovascular disease and is associated with a life expectancy shortened by up to 20 years in people with Type 1 diabetes (T1D) and 10 years in Type 2 diabetes (T2D).1 Diagnosis of diabetes has been dependent on glucose tests for a number of years, and screening relied on fasting glucose values, augmented by oral glucose tolerance testing (OGTT) if fasting glucose levels were abnormal. Recently, a World Health Organisation (WHO) consultation has concluded that glycated haemoglobin (haemoglobin A1c or HbA1c) can be used to diagnose diabetes (Table 1).2 The rationale for this is the observation that the cut point of 6.5% (48 mmol/mol) correlates with a significant increase in risk for the development of diabetic retinopathy, and the correlation is stronger than that for fasting plasma glucose.3 HbA1c reflects prevailing glycaemia over the preceding 2 or 3 months, so may not be elevated if glucose levels have risen acutely, or where there is abnormal haemoglobin metabolism. Therefore, clinicians need to …