Glycated haemoglobin variability and risk of renal function decline in type 2 diabetes mellitus: An updated...

To assess the association between glycated haemoglobin (HbA1c) variability and risk of renal function decline in type 2 diabetes mellitus (T2DM).

A comprehensive search was carried out in PubMed, Embase, Web of Science and the Cochrane Library (until 12 March 2024). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines were followed for this meta-analysis. HbA1c variability was presented as indices of the standard deviation (SD), coefficient of variation (CV), HbA1c variability score (HVS) and haemoglobin glycation index (HGI). This meta-analysis was performed using random-effect models.

Eighteen studies met the objectives of this meta-analysis. The analyses showed positive associations between HbA1c variability and kidney function decline, with hazard ratio (HR) 1.26 (95% confidence interval [CI] 1.15-1.38) for high versus low SD groups, HR 1.47 (95% CI 1.30-1.65) for CV groups, HR 1.32 (95% CI 1.10-1.57) for HVS groups and HR 1.53 (95% CI 1.05-2.23) for HGI groups. In addition, each 1% increase in SD and CV was linked to kidney function decline, with HR 1.26 (95% CI 1.17-1.35), and 1.13 (95% CI 1.03-1.23), respectively. Also, each 1-SD increase in SD of HbA1c was associated with deterioration in renal function, with HR 1.17 (95% CI 1.07-1.29).

The four HbA1c variability indicators were all positively associated with renal function decline progression; therefore, HbA1c variability might play an important and promising role in guiding glycaemic control targets and predicting kidney function decline progression in T2DM.