Design and baseline characteristics of a coronary heart disease prospective cohort: 2-year experience from the strategy of registry of acute coronary syndrome study (ERICO study)

Abstract

Introduction: Acute coronary syndrome (ACS) is an important cause of hospitalization. Although most patients are treated at local hospitals, the vast majority of registry studies are set in tertiary facilities. The ERICO study (Strategy of Registry of Acute Coronary Syndrome) was created to verify the frequency of ACS and its subtypes, the role of known or potential risk factors and long-term event rate in a community teaching hospital in the southeastern region of Brazil. Objectives: To describe the design and baseline characteristics during the two initial years of ERICO enrollment. Methods: The ERICO study is an ongoing prospective cohort. It is conducted at a secondary general hospital in Sao Paulo, Brazil. All consecutive patients, 35 years-old or older, with a diagnosis of ACS who agree to participate are enrolled in the study. Sociodemographics, medical history, clinical exam and information about hospital treatment are obtained. A brief depression questionnaire is also applied for an ancillary study. Blood samples are drawn at admission and stored. In 30-day follow-up visit, data on medical history and occurence of depressive symptoms are updated and additional blood and urinary samples are collected. Retinography, carotid intima-media thickness, heart rate variability and pulse wave velocity are performed. Questionnaires about food frequency, physical activity and sleep apnea are applied. At six months, and annually after acute event, participants are followed by phone. Results: From February 2009 to January 2011, 570 patients were enrolled. Of these, 156 (27.4%) had ST-elevation myocardial infarction (STEMI), 233 (40.9%) non ST-elevation myocardial infarction (NSTEMI) and 181 (31.7%) unstable angina (UA). Median age was 62 (interquartile interval: 54–73) years. 332 (58.2%) were men and 451 (79.1%) had 8 years or less of education. Most common primary cardiovascular risk factors were hypertension and sedentarism. Among 455 individuals who could adequately inform about previous coronary disease, only 126 (27.7%) had a prior positive history. Compared to the subgroup with STEMI, individuals with UA and NSTEMI had a higher frequency of known hypertension (p<0.01), dyslipidemia (p=0.01), sedentarism (p=0.01), prior coronary heart disease (CHD, p heart failure (p<0.01). Conclusion: In contrast to studies performed in tertiary hospitals, this community-hospital based sample has a less frequent prior history of CHD, which possibly reflects more closely a community-based setting.