Appropriateness of antibiotic treatment in intravenous drug users, a retrospective analysis.
BACKGROUND
Infectious disease is often the reason for intravenous drug users being seen in a clinical setting. The objective of this study was to evaluate the appropriateness of treatment and outcomes for this patient population in a hospital setting.


METHODS
Retrospective study of all intravenous drug users hospitalized for treatment of infectious diseases and seen by infectious diseases specialists 1/2001-12/2006 at a university hospital. Treatment was administered according to guidelines when possible or to alternative treatment program in case of patients for whom adherence to standard protocols was not possible. Outcomes were defined with respect to appropriateness of treatment, hospital readmission, relapse and mortality rates. For statistical analysis adjustment for multiple hospitalizations of individual patients was made by using a generalized estimating equation.


RESULTS
The total number of hospitalizations for infectious diseases was 344 among 216 intravenous drug users. Skin and soft tissue infections (n = 129, 37.5% of hospitalizations), pneumonia (n = 75, 21.8%) and endocarditis (n = 54, 15.7%) were most prevalent. Multiple infections were present in 25%. Treatment was according to standard guidelines for 78.5%, according to an alternative recommended program for 11.3%, and not according to guidelines or by the infectious diseases specialist advice for 10.2% of hospitalizations. Psychiatric disorders had a significant negative impact on compliance (compliance problems in 19.8% of hospitalizations) in multiple logistic regression analysis (OR = 2.4, CI 1.1-5.1, p = 0.03). The overall readmission rate and relapse rate within 30 days was 13.7% and 3.8%, respectively. Both non-compliant patient behavior (OR = 3.7, CI 1.3-10.8, p = 0.02) and non-adherence to treatment guidelines (OR = 3.3, CI 1.1-9.7, p = 0.03) were associated with a significant increase in the relapse rate in univariate analysis. In 590 person-years of follow-up, 24.6% of the patients died: 6.4% died during hospitalization (1.2% infection-related) and 13.6% of patients died after discharge.


CONCLUSIONS
Appropriate antibiotic therapy according to standard guidelines in hospitalized intravenous drug users is generally practicable and successful. In a minority alternative treatments may be indicated, although associated with a higher risk of relapse.
Mertz
Dominik
D
Division of Infectious Diseases & Hospital Epidemiology, University Hospital Basel, Switzerland. mertzd@uhbs.ch
Viktorin
Nina
N
Wolbers
Marcel
M
Laifer
Gerd
G
Leimenstoll
Bernd
B
Fluckiger
Ursula
U
Battegay
Manuel
M
D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D003140:Communicable Disease Control; D003141:Communicable Diseases / Q000188:drug therapy* / Q000209:etiology; D004359:Drug Therapy, Combination; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007275:Injections, Intravenous / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous; D013557:Switzerland / Q000453:epidemiology
D000900:Anti-Bacterial Agents