Methods
A retrospective review of general medical and surgical patients on four
wards prescribed one or more IV antimicrobials for ≥48 hours was
undertaken over two months (29 October to 21 December 2018). Patients
were identified via electronic prescribing records and excluded if:
antimicrobial(s) were prescribed for a non-infective condition;
infection required a prolonged course of IV treatment (e.g.
endocarditis); patient unable to take oral therapy or no oral option
available; patient transferred to another ward, hospital or outpatient
parenteral antimicrobial therapy; or patient died during IV
antimicrobial therapy.
An IV antimicrobial course was defined as receiving one or more IV
antimicrobials. If the timing of IV-oral-switch was deemed inappropriate
for one agent in a combination, the entire course was considered
inappropriate.
Data was collected from patients’ electronic medical records and
included: variables listed in the IV-oral-switch guideline (Supplement),
infection type, antimicrobial(s) prescribed, antimicrobial allergy
history, microbiology test results and total duration of therapy (IV
plus oral). The timing of IV-oral-switch, choice of oral
antimicrobial(s), and total duration of therapy were assessed by an ID
pharmacist and ID physician against local and national antimicrobial
prescribing guidelines [8].
The primary outcome was the proportion of patients switched to oral
antimicrobial(s) within 24 hours of meeting switch criteria. Secondary
outcomes were: median number of days of IV antimicrobial(s) before
IV-oral-switch, time delay to switch (difference in days between the
actual switch date and 24 hours after meeting switch criteria),
appropriateness of choice of oral alternative(s), and total duration of
antimicrobial therapy (IV plus oral). All outcomes were compared across
medical and surgical patients to identify differences in IV-oral-switch
and total duration of therapy. Statistical analyses were performed using
Microsoft Excel (2016) and Stata version 15. Ethical approval was
obtained from the Austin Health Human Research Ethics Committee
(LNR/18/Austin/369) and Monash University Human Research Ethics
Committee (18733).