Original article Correlation between the prevalence of type 1 diabetes with the daily insulin dose and the autoimmune process against glutamic acid decarboxylase in adults ☆ M. Khalangot ⁎, V. Kravchenko, M. Tronko, V. Gur'ianov V. P. Komisarenko Institute of Endocrinology and Metabolism, Vishgorodska, 69, 04114 Kiev, Ukraine abstract article info Article history: Received 14 May 2008 Received in revised form 8 April 2009 Accepted 20 April 2009 Available online 24 May 2009 Keywords: Type 1 diabetes mellitus Prevalence Duration Insulin dose Glutamic acid decarboxylase 65 autoantibodies In this study, we compared the rate of insulin requirement among adults with type 1 diabetes (T1D) in 24 Ukrainian regions. The glutamic acid decaroxylase 65 antibody (GADA), insulin antibody (IA), and plasma c- peptide levels were investigated. The data included the prevalent cases of T1D in Ukraine at the end of 2006. Only persons aged over 14 years at the time of inclusion into the Ukrainian register and diagnosed with diabetes before 30 years of age were included in this study (n =26796). A total of 86 T1D patients (42 males; 44 females) with a mean age of 27.5 years (0.86) and a mean diabetes duration of 10.3 (0.72) years (SE), were randomly selected from four regional diabetes registers. The GADA, IA, and the plasma c-peptide levels were also determined. The logistic regression model was used, and the odds ratio (OR) and 95% confidence interval (CI) were calculated. Furthermore, the differences in the T1D prevalence among the 24 Ukrainian regions were obtained (p b 0.001). In the “minimal” regional cluster (MIC), the prevalence rate was 6 (5–6), and in the “maximal” (MAC) regional cluster, it was -9 (8–9) per 10 000 adults. For patients with a disease duration (DD) of up to 15 years (n =13677), the daily insulin dose (DID) was observed to increase linearly with DD (R = 0.899, p b 0.001). The median insulin doses were standardized according to DD, and the values were lowest in the MIC and highest in the MAC populations: 45.89 (45.28–47.19) and 56.59 (53.33–57.88) U/24 h, respectively (p b 0.01). Furthermore, the level of HbA1c in the MAC of T1D patients was observed to be higher than that in the MIC (9.52 ± 2.24%, n = 240, and 8.57 ± 3.29%, n =111, respectively; p b 0.01). In addition, the GADA levels and persistence in the MAC patients (n = 38) were higher than that in the MIC patients (n = 48): 14.1±4.6 and 3.2±1.2 U/ml, respectively, mean±SE; p = 0.028; OR = 9.66 (3.31–28.17), p b 0.001. Adjusting for age, gender, and duration of diabetes affected the results only slightly. Furthermore, the IA and c-peptide levels and their persistence were not observed to be associated with TD1 prevalence. © 2009 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved. 1. Introduction The territorial differences in the prevalence of type 1 diabetes mellitus (T1D) around the world were previously reported [1–4], but the data were based on the study of juvenile T1D epidemiology, i.e., in patients diagnosed with T1D before the age of 15 years. These data became the basis for the epidemiological evaluation of the whole T1D patient population. With the relatively limited number of children with T1D within the current territory, less effort is required for data gathering. Besides, as age increases, it becomes more difficult to relate a diabetic condition to a certain diabetes type [5], thus, making it impossible to directly use the diabetes type data obtained from Primary Care. In modern epidemiological studies, the key data concern the age at the time of the diagnosis—patients who were diagnosed before the age of 30 years and are insulin-treated, are considered to suffer from T1D. European researchers have proved that the epidemiological characteristics of T1D in children significantly differ from that in young adults [6]. Therefore, studying the peculiarities of T1D in adults is a major concern. Furthermore, data on the number of diabetic patients usually found in the reports of the healthcare system are unstructured according to the history of the disease, and cannot be a source of epidemiological information on patients suffering from T1D. Owing to the development of the Diabetes Register in Ukraine, it has become possible to conduct analytical comparisons and further studies on almost all the T1D adult populations. The Diabetes Register contains individual, structured information on the disease history, and has already been used in some epidemiological studies [7–12]. The purpose of this study is to determine whether the insulin requirement can change systematically in T1D patients, and whether this requirement depends on the same factors that determine its prevalence. 2. Methods A database with 282 988 records of diabetic patients was developed on the basis of epidemiological analysis conducted during European Journal of Internal Medicine 20 (2009) 611–615 ☆ Part of the results of this study was presented in the 43rd Annual Meeting of the European Association for the Study of Diabetes (Khalangot M.D., Kravchenko V.I., Tronko M.D., Kulchinska Y.B., Vaiserman A.M. Association between mean daily dose of insulin in adult type 1 patients and diabetes prevalence in 24 Ukrainian regions. Diabetologia. 2007, 50 [Suppl 1] S142). ⁎ Corresponding author. Tel.: +380 44 431 0242. E-mail address: nikhalangot@ukr.net (M. Khalangot). 0953-6205/$ – see front matter © 2009 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.ejim.2009.04.008 Contents lists available at ScienceDirect European Journal of Internal Medicine journal homepage: www.elsevier.com/locate/ejim