Predicting of Trend of Hemoglobin A1c in Type 2 Diabetes: A Longitudinal Linear Mixed Model

BACKGROUND: There are some evidences that control the blood sugar decreasing the risk of diabetes complications, and even fatal. There are so many studies, but they are mostly cross-sectional and ignore the trend and hence it is necessary to implement a longitudinal study. The aim of this prospective study is to find the trend of glycosylated hemoglobin (HbA1c) over time and the associative factors on it. METHODS: Participants of this longitudinal study were 3440 eligible diabetes patients referred to Isfahan Endocrine and Metabolism Research Center during 2000-2012 who are measured 2-40 times. A linear mixed model was applied to determine the association between HbA1c and variables, including lipids, systolic, diastolic blood pressure and complications such as nephropathy, and retinopathy. Furthermore, the effect of mentioned variables on trend of HbA1c was determined. RESULTS: The fitted model showed total cholesterol, retinopathy, and the method of therapy including oral antidiabetic drugs (OADs) plus insulin and insulin therapy decreased the trend of HbA1c and high-density lipoprotein, weight, hyperlipidemia and the method of therapy including diet, and OADs increased the trend of HbA1c. CONCLUSIONS: The present study shows that regular visits of diabetic patients as well as controlling blood pressure, lipid profile, and weight loss can improve the trend of HbA1c levels during the time.