INFLUENCE OF HUMAN-IMMUNODEFICIENCY-VIRUS-1 INFECTION AND DEGREE OF IMMUNOSUPPRESSION IN THE CLINICAL CHARACTERISTICS AND OUTCOME OF INFECTIVE ENDOCARDITIS IN INTRAVENOUS-DRUG-USERS

Background: Immunosuppression caused by human immunodeficiency virus 1 (HIV) infection appears to modify the clinical characteristics and to increase the severity of several bacterial infections. The impact of HIV infection and the degree of immunosuppression on the clinical char acteristics and outcome of infective endocarditis (IE) in intravenous (IV) drug users has not been well characterized. Methods: Prospective cohort study among 292 consecutive IV drug users with IE diagnosed in 2 academic institutional hospitals in Barcelona, Spain, from January 1 , 1984, to October 31, 1995. Serostatus of HIV infection was documente d in 283 patients. We measured demographics, clinical and biological d ata, cause, echocardiographic findings, HIV serostatus and classificat ion, CD4 cell count, complications, and mortality. Results: Among the 283 episodes of IE, 216 (76.3%) were in HIV-infected patients and 67 ( 23.7%) in non-HIV-infected patients. Rate of IE per 1000 admissions ra nged from 0.17 to 0.82 per year, peaking in 1989. Characteristics of I E independently associated with HIV infection were right-side involvem ent (odds ratio [OR], 7.6; 95% confidence interval [CI], 3.5-16.7), a micro-organism different from viridans streptococci (OR, 2.5; 95% CI, 1.1-5.9), duration of drug abuse longer than 5 years (OR, 5.0; 95% CI, 2.4-10.3), and white blood cell count of no more than 10 x 10(9)/L (O R, 2.2; 95% CI, 1.1-4.2). There were no significant differences in mor tality due to IE according to HIV serostatus. Among the 216 patients w ith HIV infection, the variables independently associated with worse o utcome were CD4 cell count lower than 0.200 x 10(9)/L and left-sided o r mixed IE. Conclusions: Although there is a difference in clinical pr esentation in IE in IV drug users, outcome was similar according to th eir HIV status. However, among HIV-infected patients, severe immunosup pression and mixed or left-side valvular involvement were strong risk factors for mortality.