Use of HbA1c for new diagnosis of diabetes in those with hyperglycaemia on admission to or attendance at hospital urgently requires research

Abstract

The prevalence of diabetes in Birmingham is 11% but it is 22% in hospital inpatients. Queen Elizabeth Hospital in Birmingham (QEHB) serves a multi-ethnic population with 6% Afro-Caribbean, 19% South Asian and 70% White European. A clinical audit of 18,965 emergency admissions to QEHB showed that 5% were undiagnosed but had admission glucose in the ‘diabetes’ range and 16% were in the ‘at risk’ range. The proportion of Afro-Caribbeans (7%) and South Asians (8%) in the ‘diabetes’ range was higher than White Europeans (5%). Given the magnitude of the problem, this paper explores the issues concerning the use of reflex HbA1c testing in the UK for diagnosis of diabetes in hospital admissions. HbA1c testing is suitable for most patients but conditions affecting red blood cell turnover invalidate the results in a small number of people. However, there are pertinent questions relating to the introduction of such testing in the NHS on a routine basis. Literature searches on a topical question ‘Is hyperglycaemia identified during emergency admission/attendance acted upon?’, were performed from 2016 to 2021 and 2016 to 2022. They identified 21 different, relevant, research papers - 5 from Australia, 9 from Europe including 4 from the UK, 5 from America and 1 each from Canada and Africa. These papers revealed an absence of established procedures for the management and follow-up of routinely detected hyperglycaemia using HbA1c when no previous diabetes diagnosis was recorded. Further work is required to determine the role of reflex HbA1c testing for diagnosis of diabetes in admissions with hyperglycaemia, and the cost-effectiveness and role of point-of-care HbA1c testing.