Diabet. Med. 29, 1562–1566 (2012)
Aim To investigate the association between nephropathy and HbA1c variability (assessed as the standard deviation of each patient’s HbA1c measurements) among patients with Type 2 diabetes.
Methods Albumin excretion rate and HbA1c were measured in 2103 patients followed up for a mean 6.6 years. Multivariate Cox regression analysis was used to determine the influence of HbA1c variability on the risk of progression of nephropathy after adjustment for age, sex, duration of diabetes, baseline condition (two cohorts defined by duration of diabetes, retinopathy and albumin excretion rate), baseline HbA1c, insulin use, BMI, use of anti-hypertensive agents, smoking, lipid status, retinopathy, updated mean HbA1c and number of HbA1c measurements.
Results Nephropathy progressed in 18.3% of subjects. HbA1c variability was significantly greater among progressors than among non-progressors (12 vs. 10 mmol/mol; 1.12 vs. 0.90%; P < 0.0001) and was a significant predictor of progression of nephropathy even after adjustment for updated mean HbA1c and other risk factors (hazard ratio 1.37, 95% CI 1.12–1.69).
Conclusion In patients with Type 2 diabetes, the risk of progression of nephropathy increases significantly with HbA1c variability, independently of the influence of updated mean HbA1c.