Infective Endocarditis in Patients with Diabetes Mellitus

Background and aim of the study: Numerous studies have been conducted to investigate the conditions associated with poor outcome among patients with infective endocarditis (IE). Yet, diabetes mellitus alone has rarely been analyzed as participating in the prognosis, and few data are available relating to the clinical characteristics of IE in diabetics. The study aim was to assess the influence of diabetes mellitus on the characteristics and prognosis of IE, and to identify predictors of poor outcome among diabetic patients with this condition. Methods: The study included consecutive patients with IE who had presented to a tertiary center between 1990 and 2006. All patients underwent transthoracic and transesophageal echocardiography. Three or more blood cultures were collected from each patient. Records of all patients were collected prospectively into a computerized database. Results: Among 309 patients with definitive IE (according to modified Duke criteria), 38 (12%) had diabetes mellitus. Typically, diabetic patients were older than non-diabetics (67.1 +/- 10.4 versus 60.7 +/- 15.8 years; p<0.001), had more serious comorbidities (Charlson index 2.8 +/- 0.7 versus 1.2 +/- 0.5; p = 0.005), and a higher frequency of enterococcal endocarditis. No differences were noted between patients with or without diabetes mellitus for the valve involved, nor for the subvalvular involvement. In a multivariate analysis, diabetes mellitus was identified as an independent predictor of mortality (OR 2.49; 95% CI 1.15-5.62). Surgery was performed in the active phase in 139 patients: surgical mortality was higher for diabetic patients (29% versus 10% p = 0.049). In-hospital mortality was significantly higher among diabetic patients (34%) than in non-diabetics (20%) (p = 0.002). Enterococcal endocarditis, left ventricular ejection fraction <0.45, multi-organ failure, heart failure, persistent fever after one week of antibiotic therapy, and a Charlson index >3 were associated with an increased mortality among diabetic patients. Conclusion: Diabetes mellitus represents a relevant risk factor for a worse clinical course and outcome of IE.