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

Introduction: There is conflicting evidence regarding optimal glycaemic targets to reflect the legacy effect of hyperglycaemia in people with type 2 diabetes (T2D). We examined the risks of microvascular complications and hospital admission with glycated haemoglobin (HbA1c) levels from the diagnosis...

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Main Authors: Rami Aldafas, Yana Vinogradova, Thomas S. J. Crabtree, Jason Gordon, Iskandar Idris
Format: Article
Language:English
Published: SAGE Publishing 2025-06-01
Series:Therapeutic Advances in Endocrinology and Metabolism
Online Access:https://doi.org/10.1177/20420188251350897
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author Rami Aldafas
Yana Vinogradova
Thomas S. J. Crabtree
Jason Gordon
Iskandar Idris
author_facet Rami Aldafas
Yana Vinogradova
Thomas S. J. Crabtree
Jason Gordon
Iskandar Idris
author_sort Rami Aldafas
collection DOAJ
description Introduction: There is conflicting evidence regarding optimal glycaemic targets to reflect the legacy effect of hyperglycaemia in people with type 2 diabetes (T2D). We examined the risks of microvascular complications and hospital admission with glycated haemoglobin (HbA1c) levels from the diagnosis of T2D. Methods: We identified individuals with incident T2D from 1998 to 2007 from the Clinical Practice Research Datalink and Hospital Episode Statistics. A composite microvascular outcome was defined as a new diagnosis of neuropathy, nephropathy or retinopathy. A multivariate time-varying Cox regression analysis was performed to assess the risk of microvascular disease associated with HbA1c at five different levels (1.0% (11 mmol/mol) intervals). HbA1c 6.5%–7.5% (48.0–58.9 mmol/mol) was defined as the reference. Results: N  = 172,869 (mean age 62.6 ± 14.0 years, 54.6% female) were analysed. Average follow-up was 11.2 years. The risk of microvascular disease increased with higher HbA1c levels, the highest risk in the ⩾9.6% (⩾81 mmol/mol; hazard ratio (HR): 1.29, 95% confidence interval (CI): 1.11–1.51) and the lowest in the <6.5% (<48.0 mmol/mol; HR: 0.94, 95% CI: 0.83–1.08). The risk of hospital admission suggested a U-shaped association with HbA1c, highest risk in the lowest (<6.5% (<48.0 mmol/mol); HR: 1.04, 95% CI: 1.01–1.07) followed by HbA1c groups (8.6%–9.6% (70.0–81.0 mmol/mol); HR: 1.02, 95% CI: 0.97–1.08) while the lowest risk for hospital admission was observed for targets with the reference group (target between 6.5% and 7.5%, (48.0–58.9 mmol/mol)). Conclusion: The risk of microvascular complications was lowest when HbA1c levels were within the non-diabetic range and increased with higher HbA1c levels. The risk of hospital admission was significantly elevated in individuals with HbA1c levels below 6.5%, suggesting a potential U-shaped association, although the increased risk at higher HbA1c levels did not reach statistical significance. This highlights the importance of maintaining individualised HbA1c targets in the management of T2D from diagnosis to prevent these complications.
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spelling doaj-art-6cc077b761be4bf5b077632a1eed58462025-08-20T02:36:27ZengSAGE PublishingTherapeutic Advances in Endocrinology and Metabolism2042-01962025-06-011610.1177/20420188251350897The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK studyRami AldafasYana VinogradovaThomas S. J. CrabtreeJason GordonIskandar IdrisIntroduction: There is conflicting evidence regarding optimal glycaemic targets to reflect the legacy effect of hyperglycaemia in people with type 2 diabetes (T2D). We examined the risks of microvascular complications and hospital admission with glycated haemoglobin (HbA1c) levels from the diagnosis of T2D. Methods: We identified individuals with incident T2D from 1998 to 2007 from the Clinical Practice Research Datalink and Hospital Episode Statistics. A composite microvascular outcome was defined as a new diagnosis of neuropathy, nephropathy or retinopathy. A multivariate time-varying Cox regression analysis was performed to assess the risk of microvascular disease associated with HbA1c at five different levels (1.0% (11 mmol/mol) intervals). HbA1c 6.5%–7.5% (48.0–58.9 mmol/mol) was defined as the reference. Results: N  = 172,869 (mean age 62.6 ± 14.0 years, 54.6% female) were analysed. Average follow-up was 11.2 years. The risk of microvascular disease increased with higher HbA1c levels, the highest risk in the ⩾9.6% (⩾81 mmol/mol; hazard ratio (HR): 1.29, 95% confidence interval (CI): 1.11–1.51) and the lowest in the <6.5% (<48.0 mmol/mol; HR: 0.94, 95% CI: 0.83–1.08). The risk of hospital admission suggested a U-shaped association with HbA1c, highest risk in the lowest (<6.5% (<48.0 mmol/mol); HR: 1.04, 95% CI: 1.01–1.07) followed by HbA1c groups (8.6%–9.6% (70.0–81.0 mmol/mol); HR: 1.02, 95% CI: 0.97–1.08) while the lowest risk for hospital admission was observed for targets with the reference group (target between 6.5% and 7.5%, (48.0–58.9 mmol/mol)). Conclusion: The risk of microvascular complications was lowest when HbA1c levels were within the non-diabetic range and increased with higher HbA1c levels. The risk of hospital admission was significantly elevated in individuals with HbA1c levels below 6.5%, suggesting a potential U-shaped association, although the increased risk at higher HbA1c levels did not reach statistical significance. This highlights the importance of maintaining individualised HbA1c targets in the management of T2D from diagnosis to prevent these complications.https://doi.org/10.1177/20420188251350897
spellingShingle Rami Aldafas
Yana Vinogradova
Thomas S. J. Crabtree
Jason Gordon
Iskandar Idris
The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
Therapeutic Advances in Endocrinology and Metabolism
title The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
title_full The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
title_fullStr The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
title_full_unstemmed The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
title_short The legacy effect of early HbA1c control on microvascular complications and hospital admissions in type 2 diabetes: findings from a large UK study
title_sort legacy effect of early hba1c control on microvascular complications and hospital admissions in type 2 diabetes findings from a large uk study
url https://doi.org/10.1177/20420188251350897
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