Use of point-of-care HbA 1c measurement to estimate the level of undiagnosed diabetes mellitus among 67-year-old participants in a cardiovascular screening programme in the municipality of Viborg, Denmark.

AIMS: To determine the prevalence of unidentified diabetes mellitus among 67-year-olds in Denmark participating in a screening programme focusing on cardiovascular disease and diabetes, and to describe glycaemic levels in individuals according to point-of-care HbA1c combined with self-reported diabetes status.

METHODS: In this cross-sectional, retrospective, population-based study, all people aged 67 years living in the Viborg municipality were invited to take part in the Viborg Inter-sectorial Screening Programme (VISP), which focuses on cardiovascular disease and diabetes. The VISP study was initiated in August 2014 and is ongoing. During the first 2 years of the programme, we stratified participants into groups based on their self-reported diabetes status and a single HbA1c measurement.

RESULTS: A total of 1802 individuals were invited to participate, and 1501 consented, seven of whom were excluded because of missing data (HbA1c or diabetes status), resulting in an 82.9% participation rate (n=1494). Among those reporting not to have diabetes, 3.3% (n=45) had an HbA1c level ≥48 mmol/mol (6.5%). In the same group, 16.7% (n=226) had an HbA1c level of 41-48 mmol/mol (5.9-6.5%). Among those self-reporting the presence of diabetes, 30.1% (n=43) had an HbA1c level ≥58 mmol/mol (7.5%).

CONCLUSIONS: The prevalence of unidentified diabetes was 3.3% based on a single HbA1c measurement. Furthermore, 16.7% of those reporting not to have diabetes had an HbA1c level of 41-48 mmol/mol (5.9-6.5%), representing a subgroup with an increased risk of developing diabetes. Among those with self-reported diabetes, 30.1% had an HbA1c level ≥58 mmol/mol (7.5%) and 6.3% had a level >74 mmol/mol (8.9%).