Associations between usual glycated haemoglobin A1c and Cardiovascular Disease in Patients with Type 2 Diabetes Mellitus: A 10‐year Diabetes cohort study
Aims: The long‐term effect of glycated haemoglobin A1c(HbA1c) level on cardiovascular disease(CVD) risks among patients with type 2 diabetes remains controversial. The aim of this study was to investigate their associations. /
Materials and methods: This retrospective cohort study conducted in Hong Kong selected patients aged 45‐84 years old with type 2 diabetes mellitus and without CVD in primary care clinics within 2008‐2010. The usual HbA1c measurement was calculated using a mixed effects model to minimize regression dilution bias. The association between usual HbA1c and CVD risk was assessed by Cox regression with adjustment of baseline covariates. Subgroup analyses by patient characteristics were also conducted. /
Results: After a median follow‐up period of 8.4years (1.4 million person‐years), 174,028 patients with 34,074 CVD events were observed. Curvilinear association was found between the usual HbA1c and total CVD, stroke, heart failure and CVD mortality risk. No significant difference was found among patients with usual HbA1c7%(53mmol/mol) was 21% (HR: 1.21; 95%C.I. (Confidence Interval): 1.18‐1.23). Similar pattern was identified in patient's subgroups analysis, but the effect of usual HbA1c in younger patients were more prominent than the others. /
Conclusions: Increment in usual HbA1c level >7.0% (53mmol/mol) was associated with elevated CVD risk, but no difference was found in population with usual HbA1c<7.0% (53mmol/mol) irrespective of the patients' characteristics. For the CVD prevention, a strict adherence of HbA1c <7% (53 mmol/mol) should apply to patients with younger age
