Screen detected subjects with type 2 diabetes and impaired glucose tolerance have more adverse cardiovascular risk than subjects with impaired fasting glucose especially when they are obese: The ADDITION Netherlands study
Introduction
Type 2 diabetic patients are at increased risk for cardiovascular diseases (CVD). At the time of diagnosis diabetes patients often already have complications [1], [2]. From the Dutch Hoorn study we know that screen detected type 2 diabetic patients already have a cardiovascular risk profile typical of diabetes [3]. Furthermore, the prevalence of macrovascular disease in diabetic patients identified by screening and in newly diagnosed diabetic patients in general practice was similar [2].
Less is known about the cardiovascular risk profiles of subjects with impaired glucose tolerance (IGT) and impaired fasting glucose (IFG). Both subjects with IGT and IFG are at high risk for developing type 2 diabetes [4]. However, IGT and IFG represent different metabolic states: IGT is mainly characterized by peripheral insulin resistance, whereas IFG is associated with deficiency in insulin secretion and raised hepatic glucose output [5], [6]. Roughly, IGT is more prevalent than IFG in most populations, rises into old age and is more common in women [7], [8]. IGT is more strongly associated with cardiovascular disease than IFG [5], suggesting that postprandial hyperglycaemia has a stronger adverse influence on CVD risk than the fasting state [9], [10]. In addition, the risk for CVD is higher when IGT and IFG coexist [5]. There are conflicting study results with regard to the strength of the relation between IFG and the risk for CVD: it has even been suggested that IFG alone is not a risk factor for CVD [11], [12], [13]. On the other hand, it is stated that the impact of non-diabetic fasting hyperglycaemia as a risk factor for CVD must not be underestimated [14], [15].
Differences in cardiovascular risk factors between different categories of impaired glucose regulation may have implications for screening strategies. We hypothesized that the body mass index is an effect modifier regarding the relation between the level of glucose regulation and cardiovascular risk factors.
We performed a population-based screening for type 2 diabetes [16]. The objective of this study was to evaluate and compare the cardiovascular risk profiles of subjects with type 2 diabetes, IGT and IFG identified in the screening programme. In addition, we investigated the role of the body mass index regarding associations between glycaemic control and cardiovascular risk factors.
Section snippets
Screening procedure
The present study forms a part of the ongoing ADDITION study (Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care). From 2002 to 2003, we carried out a population-based screening programme as the first stage of the ADDITION Netherlands study. The study was approved by the Medical-Ethical Committee of the University Medical Center Utrecht. Participants gave written informed consent.
The screening algorithm is shown in Fig. 1 and has been
Results
The study population included 285 detected diabetic patients, 175 subjects with IGT and 218 with IFG.
Table 1 shows a comparison of clinical characteristics of subjects in different diagnostic categories after adjustment for age and gender. Blood pressure was similar in subjects with IGT and diabetes. BMI, waist circumference and systolic and diastolic blood pressure were significantly different between people with IFG on the one hand and those with IGT and diabetes on the other. When the 72
Discussion
This study evaluates the cardiovascular risk profiles of subjects in different categories of glucose regulation detected in a screening programme. Subjects with IFG were characterized by more favourable anthropometric measures than subjects with type 2 diabetes and IGT. These findings give support to the idea that the impact of fasting non-diabetic hyperglycaemia on CVD risk should not be overestimated. Moreover, we found no differences in blood pressure, BMI and waist circumference between
Conflict of interest statement
None declared.
Acknowledgements
The authors wish to thank the direction and the coordinating staff of the SHL Center for Diagnostic Support in Primary Care, Etten-Leur, The Netherlands, in particular, Annelies van der Smissen, Erna Erdtsieck, Paulien van Hessen, and Leandra Boonman. We are also grateful to Mardy Eckhardt and to all diabetes nurses and general practitioners participating in the ADDITION Netherlands study.
The ADDITION Netherlands study is made possible by unrestricted grants of NovoNordisk, Glaxo Smith Kline,
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