As economy and standard of living improve, the incidence of coronary heart disease (CHD) rises [1]. This is a major public health concern, as the overall mortality from acute myocardial infarction (AMI) also increases. The results of the China Patient-centered Evaluation Assessment of Cardiac Events (ChinaPEACE) showed that, from 2001 to 2011, the hospitalization rate for ST-segment elevation myocardial infarction (STEMI) increased each year [2]. According to Chinese Ministry of Health epidemiological survey data, the number of people who die from coronary heart disease each year in China is estimated at more than 1 million. Furthermore, the number of deaths of men aged 35–55 has increased rapidly [1]. Men aged <55 years and women <65 years with CHD are considered to have premature CHD [3]. With changing standards of living, dietary habits, modes of work, exercise levels, and genetic factors, the onset age for CHD has gradually decreased. Meanwhile, medical costs for young CHD patients have increased considerably. This study analyzed the clinical characteristics, risk factors, medical therapies, and prognoses of young (≤45 years) CHD patients hospitalized in two facilities in Beijing between 2010 and 2014. This study aims to provide further clinical data regarding secondary prevention and treatment of CHD.

The prevalence of cardiovascular disease in China is increasing, an estimated 2.9 billion people with cardiovascular disease in China [1], 2.7 billion people with hypertension, 7 million with stroke, 2.5 million with MI, and 4.5 million with heart failure. Li et al. reported that during the past decade in China, hospital admissions for STEMI have risen; in these patients, comorbidities and the intensity of testing and treatment have also increased [2]. Quality of care has improved for some treatments, but vital gaps persist, and in the hospital, mortality has not decreased. National efforts are needed to improve care and outcomes of STEMI patients in China. Premature coronary heart disease is defined as men with onset age <55 years, and women with onset age <65 years. The present study showed that from 2010 to 2014 in China, the proportion of young CHD patients in the department of cardiology, as well as the proportion of young CHD outpatient in the total outpatient cardiac clinic department trended upward, which may be partly associated with the rising incidence of young patients. With changing lifestyles, diets, modes of working, and genetic factors, the onset age of CHD has gradually gone down, as young CHD patients with onset age <45 gradually increase. The present study found that BMI of young CHD patients had an increasing trend; BMI was 27.6 at the upper limit, and the proportion of young obese people was greater [5]. Moreover, incidence of CHD risk factors, including hypertension, diabetes, and hyperlipidemia, increased. The proportion of smoking among young people has declined, but the overall proportion maintains a high ratio. Therefore, life-style changes, rehabilitation exercise, weight control, stopping smoking, and reducing hypertension, diabetes, and hyperlipidemia, are all key objectives for secondary prevention of young CHD.

The present study found that from 2010 to 2014, the number of young CHD patients has shown an upward trend, especiallyamong men. The rates of unstable angina and STEMI increased significantly, consistent with the ChinaPEACE results, while NSTEMI decreased. Further analysis and comparison showed that the average blood pressure of young CHD patients during hospitalization did not change significantly.

Previous studies [6] have shown that heart rate control was associated with angina symptoms and prognosis. This study showed that average heart rate remains high during hospitalization, with an average of ≥72 bmp. The use of ß-blockers increased over this 5-year period, but overall use was <80%. The incidence of hypertension, diabetes mellitus, and hyperlipidemia also rose. A report on cardiovascular disease in China in 2014 showed that the prevalence of hypertension had significantly increased [1]. In 2002, a survey showed that 18% of people in China aged >18 years had hypertension. Those with hypertension had increased to 270 million as of 2014 [1]. In the present study, the prevalence of hypertension in young CHD patients from 2010 to 2014 increased from 40.7 to 47.5%, with a slight downward trend. Diabetes is also an important risk factor in cardiovascular disease [7]. A 1999 survey showed that the prevalence of diabetes in China was about 9%, and increased to 11.6% as of 2010 [1]. The overall proportion of those with acute coronary syndrome (ACS) in youth patients (including unstable angina, STEMI and NSTEMI) increased; with an especially notable rises in the proportion of unstable angina. This may be associated with increased risk factors for young CHD, which underscores the need for secondary prevention.

The present study shows that from 2010 to 2014 fasting blood glucose levels and glycosylated hemoglobin declined slightly without statistical difference, and the incidence of diabetes increased from 20.3 to 26.1%; far from optimistic figures. Hyperlipidemia increased significantly; results from national research in 2010 showed that total cholesterol levels were ≥6.22 mmol/L for men and women, with prevalence of 3.2 and 3.4%, respectively. The results of the present study showed that from 2010 to 2014, the incidence of hyperlipidemia in young CHD patients increased from 27.3 to 35.7%, while the percentage of patients receiving statin therapy is still <80%. This study also found that BMI shows an increasing trend, while obesity and being overweight are also potential risk factors for CHD. Here we also found that CRP decreased from 2010 to 2014, which may be associated with a decrease of the proportion of myocardial infarction as shown in another report [8].

The report of cardiovascular disease in China in 2014 shows that the proportion of overweight urban and rural residents is about 30%, with obesity is at 12%. These are potentially susceptible populations for CHD. BMI showed a significantly increasing trend in young CHD patients. Obesity can promote proliferation of vascular endothelial cells and activation of inflammatory response, which are associated with endothelial dysfunction and atherosclerosis [9‐11]. Obesity can also lead to accelerated vascular aging, and increased risk of atherosclerotic disease [12‐15]. Smoking is associated with blood lipid disturbance, inflammation, and vascular endothelial dysfunction [16‐18]. Smoking has been considered one of the main risk factors for CHD among young people [19]. The present study further showed that, despite the declines in smoking and drinking, the overall proportions for both are still high, and the average incidences exceed 50 and 25%, respectively. Analysis of laboratory test results showed that total cholesterol and triglyceride levels showed a downward trend, while LDL cholesterol did not change significantly. This is associated with lack of exercise, obesity, and other lifestyle choices, as also shown in both the Coronary Artery Risk Development in Young Adults Study and Cardiovascular Risk in Young Finns Study [20, 21]. A large number of studies proved statins could reduce the incidence of cardiovascular events and inhibit development of coronary plaque [22]. However, the present study showed that in the hospital, <80% of young CHD patients received statin therapy. We also found the proportion presented with upstream trend, which was partly due to lack of exercise.

The olderly patients presented with multiple, diffuse, and calcification lesions, while young CHD patients presented with acute onset, less collateral circulation, and more total occlusive disease [23]. The present study showed that young CHD patients presented with single branch lesions, mainly in the LAD, followed by RCA, and LCx. As per ACC/AHA classification [24], this study showed the incidence of simple type A lesions had reduced, while the complex type C lesions increased over the course of the examined years. The events in-hospital, overall mortality, and cardiogenic shock trended downward trend, and major bleeding, malignant ventricular arrhythmia, and acute or subacute thrombus demonstrated no difference. This may be partly associated with improvements in medical and interventional treatments. No significant improvement in MACE, including cardiac death, myocardial infarction, CABG, PCI, and stroke incidence, was found after 1 year.

Ultimately, this study confirmed that from 2010 to 2014, with updated guidelines applied in clinical treatment, secondary prevention has gradually been promoted. However, many shortcomings are still seen, such as the rising incidence of hypertension, diabetes, hyperlipidemia, and higher BMI. The ratio of smokers is still high. In medical treatment, use of aspirin, clopidogrel, statins, and ß-blockers have improved overall, but the control of heart rate and blood lipids levels are still low. A great deal of progress is still needed for young patients regarding primary and secondary prevention of CHD, including BMI control, smoking cessation, rehabilitation exercise, and reducing hypertension, diabetes and hyperlipidemia.