Association between route of illicit drug administration and hospitalizations for infective endocarditis

Abstract

Objective: This study examined the association between the route of drug administration and being hospitalized for infective endocarditis among 4817 treatment-seeking illicit drug users in Finland.

Methods: Cox regression models were used to examine the association between the route of drug administration and infective endocarditis hospitalization, adjusted for age, gender, and homelessness. Cases of infective endocarditis as a primary/main diagnosis were tracked using the 10th version of the International Classification of Disease code I33.

Results: In all, 47 persons had a primary diagnosis of infective endocarditis. These 47 persons contributed a total of 95 hospitalizations and their total length of hospital stay was 1393 days. There was a statistically significant difference in hospitalizations between injectors and non-injectors (Log-Rank test p = 0.018). Univariate Cox model showed that injectors had higher hazard or risk for infective endocarditis hospitalization compared to non-injectors (hazard ratio: 2.04, 95% confidence interval: 1.12-3.73, p = 0.020). After adjusting for age, gender, and homelessness in the multivariate model, the elevated hazard among injectors compared to non-injectors remained statistically significant with adjusted hazard ratio of 2.12 (95% confidence interval: 1.11-4.07, p = 0.024).

Conclusion: The study findings suggested a need to boost harm reduction measures targeting high-risk injecting and other health behaviors among injecting drug users in order to reduce their hospitalizations for infective endocarditis.

Keywords: Infective endocarditis; cohort study; hospitalization; injecting drug use; register linkage; substance abuse.

Figure 1.

Cumulative survival of injectors and non-injectors during the follow-up period.