Changes in HbA1c and frequency of measuring HbA1c and adjusting glucose-lowering medications in the 10years following diagnosis of type 2 diabetes: a population-based study in the UK.

Abstract

The aim of this work was to study levels of HbA1c and patterns of adjusting glucose-lowering drugs in patients with impaired glycaemic control over 10years after diagnosis of type 2 diabetes. We studied 4,529 individuals in The Health Improvement Network Database newly diagnosed with type 2 diabetes in the year 2000. From 6months to 10years after diagnosis, the HbA1c increased from 7.04% (53.4mmol/mol) to 7.49% (58.3mmol/mol) (average annual change: 0.047% [0.51mmol/mol]). The greatest annual change occurred between 6months and 2years (0.21% [2.30mmol/mol] increase per year, p < 0.001), followed by the 2-5year time period (0.033% [0.36mmol/mol] increase per year, p < 0.001). No significant increase in HbA1c occurred between 5 and 10years (p = 0.20). In multivariable analyses, patients who were younger (p < 0.001), with higher BMI (p = 0.033) and who were current insulin users (p = 0.024) at diagnosis had greater increases in HbA1c between 6months and 2years. For individuals with HbA1c above 7.0% (53mmol/mol) the mean time to next measurement of HbA1c was 0.53years and increase in doses or changes to other glucose-lowering medications were performed in 26% of cases. HbA1c increases by approximately 0.5% (5mmol/mol) over 10years after diagnosis of type 2 diabetes, with the main increase appearing in the first years after diagnosis. More frequent monitoring of HbA1c and adjustments of glucose-lowering drugs may be essential to prevent the decline.