The incidence of DM is increasing worldwide, and CVD is one of the leading causes of mortality in these patients. Therefore, this thesis aims to identify risk factors for CVD among the Hungarian population with DM, to identify opportunities for evaluating the risk of CVD in these patients, and to find ways to prevent CVD in patients with DM. Within the framework of this thesis, we have completed three separate studies. The results of this thesis indicate that, in addition to age and gender, cardiovascular risk factors such as hypertension and hypercholesterolemia increase the risk of CVD in patients with DM, which highlights the importance of interventions to regularly monitor and maintain these risk factors in patients with DM. In addition, depression is one of the risk factors for CVD in patients with DM, indicating the importance of ongoing mental health care for these patients. While socioeconomic factors such as education level and percieved income level have been found to negatively affect the risk of CVD in patients with DM, lifestyle factors such as BMI, smoking, and alcohol consumption have not been found to have effect among this population. When the period of data collection was included in the multivariate model for determining the risk factors for CVD in DM, a trend of decreasing the risk of CVD in the Hungarian population from 2009 to 2019 was observed, and it was considered necessary to determine in detail which factors contribute to this trend. In a study evaluating the risk of CVD in patients with T2DM, the risk was found to be associated with age and gender, as well as clinical laboratory parameters related to lipid metabolism—such as total cholesterol, LDL, and triglycerides—and renal function markers including uric acid, creatinine, and eGFR, with strong evidence supporting these associations. In a Cox proportional hazards regression analysis evaluating the risk of CVD in patients with T2DM, there was evidence that elevated triglyceride levels and reduced eGFR were associated with an increased risk of CVD, while lower serum creatinine levels were associated with a reduced risk. This demonstrates these laboratory parameters are important in assessing the risk of CVD in patients with T2DM, and thus in reducing and preventing the risk. In addition, the risk of CVD was lower in patients with "proper care" or HbA1c measured once every 6 months, indirectly indicating that regular monitoring of blood sugar and maintaining it at an appropriate level is important in reducing the CVD risk in these patients. Our initial research demonstrated that the prevalence of CVD is declining among patients with DM in Hungary, and lifestyle-related modifiable risk factors did not considerably affect CVD risk for these patients. We hypothesized that this pattern of declining CVD prevalence in patients with DM may be related to the quality of diabetes care, particularly the effects of some new-generation blood sugar-lowering medications, as the second study found that the "proper care" variable had a substantial impact on the risk of CVD. Therefore, we examined the effects of blood sugar-lowering medications on the risk of CVD in patients with T2DM, and the third study conducted within the thesis found that SGLT-2 inhibitors have a protective effect against HF in patients with T2DM.