The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study

Abstract

Association between small vessel diseases, hospital admission and HbA1c levels in people with type 2 diabetes In this study, we examined the risks of developing complications affecting the eyes, kidneys, nerve damage and hospital admission with blood sugar levels in people from diagnosis of their type 2 diabetes. We identified individuals with newly diagnosed type 2 diabetes from 1998-2007 and followed patients up for a further 11 years. Patients’ data was collected from the Clinical Practice Research Datalink and Hospital Episode Statistics. A combine small vessel disease outcome was defined as a new diagnosis of nerve damage, kidney disease and eye disease. We used statistical technique to assess the risk of small vessel disease associated with five different levels of glucose control, assessed by a measure of blood test called HbA1c. Data of 172,869 patients (average age 62.6 ± 14.0 years, 54.6% female) were analysed. Average follow-up was 11.2 years. The risk of small vessel diseases increased with higher HbA1c levels, the highest risk in the ⩾9.6% and the lowest in the <6.5%. The risk of hospital admission demonstrated a U-shaped association with HbA1c, highest risk in the lowest (<6.5%) and highest HbA1c groups. Conclusion The risk of small vessel diseases was lowest when HbA1c levels were within the non-diabetic range and increased with higher HbA1c levels. The risk of hospital admission was highest in both the lowest (<6.5%) and highest (8.6-9.6%) HbA1c categories, demonstrating a U-shaped association. This highlights the importance of maintaining individualised HbA1c targets in the management of T2D from diagnosis to prevent these complications.