Relationship between HbA1c and all-cause mortality in older patients with insulin-treated type 2 diabetes: results of a large UK Cohort Study

our aim was to study the relationship between HbA(1c) and cardiovascular morbidity and all-cause mortality among older insulin-treated patients with type 2 diabetes (T2D) after adjustment for multiple confounders. data for 4589 adults with T2D (> 65 years) on insulin treatment were sourced from 532 UK General Practices via the Health Improvement Network (THIN) database. Cox proportional hazard models and KaplanMeier estimators were fitted to derive the hazards of all-cause mortality by HbA(1c) categories (< 6.5, 6.57.4, 7.58.4, 8.59.4, 9.510.4, 10.511.4%; and 11.5% and above) after 5 years of follow-up following insulin initiation. we observed a U-shaped relationship between all-cause mortality and HbA(1c), with the lowest risk seen in the HbA(1c) range of 6.57.4% and marked increased in risk with HbA(1c) > 11%. The highest mortality risks of 31 and 40% were significantly associated with the lowest (< 6.5%) and highest (11.5% and above) HbA(1c) categories: aHR: 1.31; (95%CI: 1.101.56; P = 0.002) and aHR: 1.40; (95%CI: 1.011.96; P = 0.039), respectively. both low and high HbA(1c) were associated with increased all-cause mortality, among older patients with insulin-treated T2D. This cohort study supports the need for individualisation of care and suggests better outcomes with HbA(1c) levels around 6.57.4% and markedly excess risk with HbA(1c) > 11%.