The changing epidemiology and clinical features of infective endocarditis: A retrospective study of 196 episodes in a teaching hospital in China

Background: Infective endocarditis is an uncommon but life-threatening infectious disease. To our knowledge, current investigations of the characteristics of infective endocarditis in our region are scarce. In this study, we aimed to investigate the changes in the epidemiology and clinical features of infective endocarditis. Methods: A retrospective analysis of clinical data was performed using 196 infective endocarditis cases diagnosed between June 2004 and December 2012 at The First Affiliated Hospital of China Medical University. A comparative analysis of clinical risk factors was also included. Results: The mean age of the patient cohort was 43.5 (29.0-55.8) years old. Of the 196 cases studied, 128 cases (65.3%) were left native valve infective endocarditis, 13 cases (6.6%) were left prosthetic valve infective endocarditis, and 47 cases (24%) were right valve infective endocarditis. In addition to natural valve endocarditis, many patients also exhibited various types of cardiopathy: 72 cases (36.7%) had congenital cardiovascular malformations, 37 cases (18.9%) had idiopathic mitral valve prolapse and 31 cases (15.8%) had no significant cardiac disease. The primary clinical manifestations that were observed included 168 cases with fever (85.7%), 131 cases with anemia (66.8%), 114 cases with hematuria (58.2%) and 58 cases with splenomegaly (29.6%). Positive blood cultures were detected in 96 cases (49%); the most commonly detected organism was Streptococcus viridans (41 cases; 42.7%), followed by 18 cases (18.8%) of Staphylococcus aureus and 10 cases (10.4%) of Enterococcus. With respect to risk factors, infection with Staphylococcus aureus or gram-negative bacilli (OR = 18.81, 95% CI = 2.39-148.2), congestive heart failure (OR = 8.854, 95% CI = 1.34-54.7), diabetes (OR = 7.224, 95% CI = 1.17-44.7) and age >= 60 years (OR = 6.861, 95% CI = 0.94-50.1) were major prognostic risk factors. Conclusion: Infective endocarditis is more common than previously believed, but there are regional differences with respect to the epidemiological and clinical characteristics of infective endocarditis, and its etiology is diverse and complicated. Our study of the clinically diagnosed cases of infective endocarditis verified the regional characteristics of infective endocarditis using a straightforward retrospective analysis. The geographic variations we observed in the study will be of important value to clinical diagnosis in our region.