Importance of Lipid Levels in Elderly Diabetic Individuals Baseline Characteristics and 1-Year Survey of Cardiovascular Events

Abstract

nvestigators in Western countries have reported that patients with both hypercholesterolemia and type 2 diabetes mellitus (DM) have a higher risk of coronary events (ie, acute myocardial infarction and sudden cardiac death) than patients with hypercholesterolemia alone. 1 The incidence of ischemic heart and cerebrovascular diseases (IHD, CVD) in patients with type 2 DM is reported to be high in Japan, 2 so it has been speculated that when hypercholesterolemia is complicated with DM, the risk of IHD (and perhaps CVD) is also increased in Japanese patients, but direct evidence is limited because there have been few large-scale epidemiological surveys. Recently, the J-LIT study reported a relationship between plasma lipid and coronary events, 3 but it is a study of hypercholesterolemic patients and important information about DM (such as glycohemoglobin) was not studied. Furthermore, only individuals aged 69 years or younger were assessed, and no data were available for the elderly; in addition, all patients were medicated with simvastatin. Therefore, it is worthwhile analyzing the data from the Japan Cholesterol and Diabetes Mellitus investigation (Japan-CDM), which was a nationwide observational cohort study of a large number of diabetic individuals who were treated in clinical practice; it was designed to assess the relationship between lipid levels and the incidence of cardiovascular diseases in Japanese diabetic individuals. 4 In Japan, cholesterol-lowering therapy is well established, but evidence from large-scale studies is not available in relation to plasma levels of low-density lipoprotein (LDL) in diabetic individuals, and at the beginning of the present study (2004), atrovastatin was the only Background The respective incidences of ischemic heart and cerebrovascular disease (IHD, CVD) are high in diabetic individuals. Complications of dyslipidemia increase the risk, but direct evidence is limited, so a cohort prospective study (Japan-CDM) was conducted. Methods and ResultsThe study group comprised 4,014 subjects with type 2 diabetes (1,936 women, 2,078 men; mean age 67.4±9.5 years) who were divided into dyslipidemic patients (79.1%) with or without medication (medicated, 50.9%; not medicated, 28.2%) and normo-lipidemic patients (20.9%). The incidence of IHD, CVD, arteriosclerosis obliterans (ASO), congestive heart failure (CHF) and death was assessed. IHD and CVD occurred in 0.82 and 0.67%, respectively, during the first year following registration. CHF, ASO and sudden death occurred in 0.27%, 0.12% and 0.12%, respectively. There was a significant statistical difference in the relation of elevated levels of high-density lipoprotein-cholesterol to lower rates of IHD and CVD. IHD and CVD in males were dependent on the level of low-density lipoprotein-cholesterol (LDL-C): 0.45%, 1.56%, 1.78%, 1.91% and 2.34% were observed in less than 2.11, 2.11-2.62, 2.63-3.15, 3.16-3.67, and more than 3.68 mol/L of LDL-C. In the lowest LDL-C group, death other than from vascular diseases was increased. Age, sex (male) an...