Achievement of Glycated Hemoglobin Targets and Associated Factors in Older Adults with Type 2 Diabetes in Vietnam: a Cross-Sectional Study

Objective: To examine the achievement of individualized glycated hemoglobin (HbA1c) targets and to explore its association with geriatric characteristics and patterns of oral antidiabetic drug use among older adults with type 2 diabetes (T2D) in Vietnam. Material and methods: A cross-sectional study of outpatients aged ≥ 60 years with T2D was conducted at the National Geriatrics Hospital, Vietnam (December 2024–June 2025). Individualized HbA1c targets were defined as < 7.5% for robust individuals and < 8.0% for those with complex health (cognitive impairment, functional dependence, or ≥ 4 comorbidities). Sociodemographic, diabetes-related, and geriatric characteristics were collected, and logistic regression models identified factors associated with target attainment. Results: Out of the 504 participants (mean age 74.3 ± 7.4 years; 62.5% female), 81.6% achieved their individualized HbA1c target. Geriatric syndromes were prevalent, including sarcopenia (37.9%) and frailty (16.7%). A significant paradox emerged: compared to monotherapy, the use of dual [adjusted odds ratio (aOR) = 0.40, 95% confidence interval (CI): 0.18–0.87) and triple or more OAD combinations (aOR = 0.14, 95% CI: 0.06–0.31) was associated with substantially lower odds of achieving glycemic targets. Higher education was associated with better control. Conclusions: While a high proportion of older Vietnamese adults achieve individualized HbA1c goals, polypharmacy is paradoxically linked to poorer glycemic control. This highlights the limitations of a purely pharmacologic approach and underscores the critical need to integrate routine geriatric assessment into diabetes management to guide safer and more effective treatment strategies.