Treatment of cardiovascular risk factors in type 2 diabetes : time trends and clinical practice

Sammanfattning: Objectives Patients with type 2 diabetes are at much greater risk of developing cardiovascular diseases (CVD), including coronary heart disease (CHD), compared to non-diabetics. The lowering of glucose, blood pressure, and plasma lipid levels has been shown to reduce CHD risk, and treatment goals for these risk factors are now part of clinical practice guidelines. However, the incidence and outcome of CHD in diabetic patients does not show the same favourable trend as in the general population. Thus, the overall aim of the thesis was to investigate how the treatment goals for CVD risk factors contained in the national guidelines for diabetes care were reflected in clinical practice, and to explore factors that might influence the remaining high incidence of CHD in the type 2 diabetes population. Research designs and results I. The effectiveness of the introduction of treatment goals for dyslipidaemia was evaluated in a retrospective observational population-based cross-sectional study of 971 diabetic patients participating in the Västerbotten Intervention Programme (VIP) 1995–2004. There was a stronger trend of decrease in cholesterol levels among patients with diabetes compared to the non-diabetic population in 2000–2004. Increased use of lipid-lowering agents influenced the trend in diabetic patients, even though only 25.3% received lipid-lowering treatment after the introduction of the new guidelines. II. The experiences of general practitioners relating to treatment practice for type 2 diabetes with specific focus on the prevention of cardiovascular disease were explored in a focus group study. The overall theme was ‘dilemmas’ in GPs’ treatment practice for patients with type 2 diabetes. Five main dilemma categories were identified. First, GPs were hesitant about labelling a person who feels healthy as ill. Second, as regards communicating a diabetes diagnosis and its consequences, GPs were unsure as to whether patients should be frightened or comforted. Third, GPs experienced uncertainty in their role: should they take responsibility for the care or not? Fourth, GPs expressed concern over a conflict between lifestyle changes and drug treatment. Fifth, the GPs described difficulties when attempting to translate science into reality. III. Screening for microvascular and coronary heart disease according to national guidelines was evaluated in a cross-sectional study of 201 screening-detected patients with type 2 diabetes 1.5±0.7 years after diagnosis. A larger proportion of diabetic patients was screened for nephropathy and retinopathy than for CHD. Twenty-three percent of the patients had minor or major ECG abnormalities, but ECG findings seemed to have little or no impact on CHD prevention using lipid-lowering medication and ASA. A clinical history of CHD correlated with a larger proportion of patients receiving secondary prevention. IV. Time trends relating to the achievement of treatment goals and 10-year CHD risk at three years of diabetes duration were studied in 19,382 patients with type 2 diabetes without CHD, who were reported by primary health care sources in the National Diabetes Register in 2003–2008. National treatment goals for glycaemia, blood pressure, total cholesterol, and LDL cholesterol were achieved in 78.4%, 65.5%, 55.6%, and 61.0%, respectively, of the diabetic patients in 2008 following a trend of improved results in 2003–2008. Absolute 10-year risk of CHD increased between year of diagnosis and follow up in a studied subgroup while modifiable risk decreased. Conclusions The introduction of treatment goals for dyslipidemia in Swedish national guidelines in 1999 were reflected in lowered cholesterol levels in people with type 2 diabetes. Since the introduction of the guidelines, an increasing number of diabetic patients are treated in accordance with guidelines. A remaining microvascular focus on the patients together with the revealed dilemmas within the GP’s consultation with diabetic patients might negatively influence the remaining high incidence of CHD in the type 2 diabetes population. Lipid levels, blood pressure and smoking are targets for further improvements.