Impact of haemoglobin A1c trajectories on chronic kidney disease progression in type 2 diabetes

Aim To characterize haemoglobin A1c (HbA1c) trajectories and examine their associations with chronic kidney disease (CKD) progression. Methods This was a prospective cohort study on 770 patients with type 2 diabetes mellitus (T2DM) attending a diabetes centre in 2002-2017. Group-based trajectory modelling was used to identify HbA1c trajectories. Cox proportional hazards models were used to examine association between the trajectories and CKD progression which was defined as deterioration across the Kidney Disease: Improving Global Outcomes estimated glomerular filtration rate categories with >= 25% drop from baseline. Results We identified four HbA1c trajectories: 'near-optimal stable' (49.1%), 'moderate stable' (37.9%), 'moderate-increasing' (6.0%) and 'high-decreasing' (7.0%). Over a median follow-up period of 4.6 years (interquartile range 2.5-5.6), CKD progression occurred in 35.6% of patients. The risk of CKD progression was significantly higher in the moderate-increasing with adjusted hazard ratios (HR) 2.23 (95% confidence interval (CI) 1.09-4.57). After additional adjustment for mean HbA1c, the association between the moderate-increasing subgroup and CKD progression remained significant at HR 3.07 (95% CI 1.08-8.77). Conclusion Moderate-increasing HbA1c trajectory is associated with renal disease progression in patients with T2DM, independent of mean HbA1c. The deleterious effects of deteriorating HbA1c trajectory highlight the importance of achieving sustained good glycaemic control in diabetes management.