Age-related differences in diabetes care outcomes in Korea: a retrospective cohort study

Background: Age-related differences in diabetes outcomes are important both for clinical and policy considerations. To clarify the basis of such differences, we investigated patterns of associations for age in relation to hospitalization and glycemic control and examined the role of other factors. Methods: 4471 patients with diabetes aged 40-79 years were drawn from a retrospectively retrieved National Health Insurance Cohort. Using logistic regression, risk factors measured over the two years (2007-2008) were examined for their associations with hospitalization and poor glycemic control during the last year (2009) of follow-up. Results: Compared to the middle-aged patients, older patients were more likely to have been hospitalized (Adjusted odds ratio (ORadjusted) = 1.97(95% CI = 1.28, 3.04) for the oldest group (ages 70-79) vs youngest group (ages 40-49)) but less likely to have poor glycemic control (ORadjusted = 0.45 (95% CI = 0.37, 0.56) for the oldest group vs youngest group). Older patients were also less likely to be obese but had more complications, longer duration of diabetes, lower continuity of care, and higher blood pressure and total cholesterol level. The pattern of associations for hospitalization and glycemic control was not uniform across the risk factors, sharing only a few common factors such as the duration of diabetes and blood pressure. In general, poor glycemic control was affected predominantly by metabolic management, while hospitalization was strongly related to functional status (i.e., number of complications) and care quality measures (i.e., continuity of care). Conclusion: Hospitalization was higher among the older diabetic patients, despite better glycemic control. Factors were differently associated with the two diabetes-related outcomes, providing more comprehensive risk profiles for hospitalization. The co-existence of improved glycemic control and increased hospitalization among older diabetic patients suggests an extension of a geriatric evaluation to wider functional and comorbidity status.