Patients with Infectious Endocarditis and Drug Dependence Have Worse Clinical Outcomes after Valvular Surgery

Background: Patients with infective endocarditis (IE) are at high risk for post-operative morbidity and death, which might be associated with drug abuse. The purpose of this study is to evaluate the impact of drug dependence on outcomes in patients who have IE and undergo valvular surgery (VS). Patients and Methods: The Nationwide/National Inpatient Sample 2001-2012 was queried to select patients with IE who had elective VS using International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis and procedure codes. Among them, patients with drug dependence (PDD) were identified, and their health status and post-operative outcomes were compared with those in patients without drug dependence (control group). Chi-square and Wilcoxon rank sum tests as well as multi-variable regression analysis were used for statistics. Results: A total of 809 (12.9%) PDD of the 6,264 patients who underwent VS were evaluated. They were younger compared with those in the control group (39.0 ± 10.8 y vs. 54.4 ± 14.8 y; p < 0.0001), had less age-related co-morbidities such as hypertension, diabetes mellitus, congestive heart failure, renal failure, obesity, but greater rates of alcohol abuse, liver disease, and psychoses. Despite the younger age and fewer co-morbidities, PDD compared with control patients were more likely to have post-operative complications develop overall (odds ratio [OR] = 1.6; 95% confidence interval [CI] 1.34-2.01), including infectious complications (OR = 1.5; 95% CI 1.27-1.78), specifically pneumonia (OR = 1.4; 95% CI 1.14-1.74) and sepsis (OR = 1.4; 95% CI 1.16-1.63), renal complications (OR = 1.5; 95% CI 1.23-1.77), and pulmonary embolism (OR = 1.9; 95% CI 1.44-2.52). Further, PDD had 11% longer hospital length of stay than those in the control groups (p < 0.0001). We did not find significant difference in hospital deaths, however, between these groups. Conclusion: Drug dependence is associated with worse post-operative outcomes in patients with infective endocarditis who underwent valvular surgery and lengthens their hospital stay.