Longitudinal trends in HbA1c and associations with comorbidity and all-cause mortality in Asian patients with type 2 diabetes: A cohort study

Aims: This study examined longitudinal trends in HbA1c in a multi-ethnic Asian cohort of diabetes patients, and the associations of these trends with future risk of acute myocardial infarction (AMI), stroke, end stage renal failure (ESRD) and all-cause mortality. Methods: 6079 participants with type 2 diabetes mellitus in Singapore were included. HbA1c measurements for the five years previous to recruitment were used to identify patterns of HbA1c trends. Outcomes were recorded through linkage with the National Disease Registry. The median follow-up for longitudinal trends in HbA1c was 4.1 years and for outcomes was between 7.0 and 8.3 years. HbA1c patterns were identified using latent class growth modeling, and associations with outcomes were analyzed using Cox proportional hazards models. Results: Four distinct HbA1c patterns were observed; "low-stable" (72.2%), "moderatestable" (22.0%), "moderate-increase" (2.9%), and "high-decrease" (2.8%). The risk of comorbidities and death was significantly higher in moderate-increase and high-decrease groups compared to the low-stable group; the hazard ratios for stroke, ESRD, and death for moderate increase group were 3.22 (95% CI 1.27-8.15), 4.76 (95% CI 1.92-11.83), and 1.88 (95% CI 1.15-3.07), respectively, and for high-decrease group were 2.16 (95% CI 1.02-4.57), 3.05 (95% CI 1.54-6.07), and 2.79 (95% CI 1.97-3.95), respectively. Individuals in the moderate-increase group were significantly younger, with longer diabetes duration, and greater proportions of Malays and Indians. Conclusions: Deteriorating HbA1c pattern and extremely high initial HbA1c are associated with increased risk of long-term comorbidities and death. Therapeutic interventions to alter longitudinal HbA1c trends may be helpful in reducing this risk. (C) 2017 The Authors. Published by Elsevier Ireland Ltd.