HbA1c for Diabetes Screening in Acute Coronary Syndrome: time for a reappraisal of the guidelines?

Diabetes is highly prevalent in individuals with acute coronary syndrome (ACS). Current NICE guidelines recommend diabetes screening of hyperglycaemic patients using a fasting plasma glucose after 4 days from admission. In 2012 the World Health Organisation (WHO) approved the use of HbA1c in the diagnosis and targeted screening for type 2 diabetes. We introduced a service improvement project using HbA1c for diabetes screening in patients with no previous diagnosis of diabetes admitted with ACS regardless of glycaemic state.An initial retrospective audit utilised 21 months of data from the MINAP database to identify patients meeting current NICE criteria for diabetes screening. A prospective service improvement project was undertaken over a 4 month period using HbA1c as a universal screening test to categorise ACS patients based on WHO criteria.The retrospective audit identified 93 of 420 (22%) patients with pre-existing diabetes and 8 of the remaining 327 (2.4%) were hyperglycaemic, thus meeting NICE criteria for diabetes screening. In the service improvement project 2/49 patients (4%) met NICE criteria for diabetes screening. Twenty six of these 49 patients had a HbA1c test on admission and 17/26 (65.4%) were classified as probable diabetes or high risk.A significant proportion of ACS patients have diabetes, which may be undetected by current NICE criteria. Universal HbA1c testing offers utility as a simple and effective screening test for diabetes in the ACS population.