243350 Trends in injection drug use-related infective endocarditis in the United States, 1993-2007

Tuesday, November 1, 2011

Wendy Tseng , School of Medicine, Dept of Family Community Medicine, University of California San Francisco, San Francisco, CA
George Jay Unick, PhD, MSW , School of Social Work, University of Maryland, Baltimore, MD
Daniel Rosenblum, PhD , Department of Economics, Dalhousie University, Halfax, NS, Canada
Daniel Ciccarone, MD, MPH , Family and Community Medicine, University of California San Francisco, San Francisco, CA
Background: A previous study showed that the number of hospitalizations for injection drug use (IDU)-related infective endocarditis (IE) increased by 66 percent nationwide between 2000 and 2003. We extend this analysis to a 15-year timeframe, 1993-2007, and explore associated factors for the observed IDU-related IE trends.

Method: We used data from the Nationwide Inpatient Survey (NIS), a national probability sample of US hospital admissions. Algorithms based on international classification of diseases (ICD-9) codes were created to assess for admissions co-diagnosed for IDU and IE. Admissions with non-IDU risk factors for IE, e.g., prosthetic valve replacements, rheumatic heart disease, and congenital heart disease, were excluded.

Results: IDU-related IE cases decreased by 39 percent between 1993 and 2000 (8.68 to 5.26 cases per 1,000,000 US population). Between 2000 and 2006, however, the number of hospitalizations for IDU-related IE steadily increased by 66 percent (5.26 to 8.83 cases per 1,000,000), with a slight fall-off in 2007. Multivariate analysis of the IE trend reveals a statistically significant U-shaped quadratic curve (p=0.007).

Discussion: This study reveals a rebound, following a historic decline, in IDU-related IE cases in the US from 1993 to 2007. Drug market cycles are relatively unexamined as public health risks, e.g. our previous work demonstrated a historic 72% decline in nationwide retail heroin price between 1990 and 2004. We will present the results of multivariate modeling exploring market availability factors, including price and purity, of heroin and methamphetamine, as associated risks for the rise in IDU-related IE during the past decade.

Learning Areas:
Biostatistics, economics
Public health or related research

Learning Objectives:
1. Characterize trends in injection drug use-related infective endocarditis in the US 2. Examine factors associated with the rise in injection drug use-related infective endocarditis

Keywords: Injecting Drug Use, Heart Disease

Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: None

Qualified on the content I am responsible for because: I am qualified to present because I am a medical student researching public health concerns.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.