In-hospital and long-term mortality in infective endocarditis in injecting drug users compared to non-drug users: a retrospective study of 192 episodes.

In a retrospective study, in-hospital and long-term mortality for patients with infective endocarditis (IE) was analysed. The study was conducted at a department of infectious diseases in Stockholm, Sweden. Mortality was compared between injecting drug users (IDUs) and patients without drug abuse (non-IDUs). 192 episodes of IE from 1995 to 2000 were analysed, 60 in IDUs and 135 in non-IDUs, median follow-up 4.4 y. Episodes were classified using the Duke criteria: 145 definite and 47 possible. Of 53 definite episodes in IDUs, 55% were right-sided IE and 43% left-sided IE (including combined left- and right-sided). Surgical treatment was used in 34/145 definite episodes, all being left-sided IE. The in-hospital mortality was 14/145 (9.6%). There was no difference in in-hospital mortality between patient groups with left-sided IE. The IDU patients with left-sided IE had a higher long-term mortality with the increased mortality rate explained by late deaths in the surgically treated IDUs. Treatment results for IDUs with right-sided IE were good with no in-hospital mortality, no relapses and no increase in long-term mortality. This difference in prognosis between left-sided and right-sided IE in IDUs makes high quality echocardiography important to identify patients with left-sided IE and worse prognosis.