The observed reduction in DOT and LOT can be reasonably hypothesized to produce a number of positive downstream effects. There is growing evidence to show that a reduction in antimicrobial use can result in a decrease in AMR, in particular within the hospital setting [16, 17]. Lower DOT/LOTs reflect reduced unnecessary use of antimicrobials and may lead to reduced antimicrobial resistance rates, reduced Clostridioides difficile infections and reduced infections due to MRSA, carbapenem resistant Pseudomonas aeruginosa and extended spectrum beta lactamase (ESBL)-producing enterobacterales [18].
Additionally, AMS programs and interventions that improve antimicrobial prescribing have been shown to increase cure rates, decrease treatment failures and decrease mortality from infection [19]. Of the 34 patients which received broad spectrum antimicrobials which triggered the antibiotic timeout function, 22 (64.7%) of these either resulted in an intentional discontinuation of therapy or a de-escalation to oral antimicrobials. AMS programs that look to prescribe according to guidelines (including recommended durations) and de-escalate therapy when appropriate have previously demonstrated a 35% relative risk reduction for mortality associated with guideline-adherent therapy and a 56% decrease in mortality associated with de-escalation of therapy [20].
The cost saving benefits of AMS intervention tools have been well described with AMS programs reducing antimicrobial costs by an average of 33.9% and length of stay by 8.9% [18]. The demonstrated reduction in DOT/LOTs directly reflects reduced antimicrobial use and could be attributed to the antibiotic timeout function prompting treating teams to consider ceasing antimicrobial therapy when indicated. Furthermore, intravenous antimicrobial therapy may often be the rate-limiting step preventing a patient’s discharge and the antibiotic timeout function prompting teams to consider an IV-to-oral change in antimicrobial therapy could be a contributing influence [21, 22].
The default number of days an antimicrobial will be prescribed is automatically set to 5 days and unless treating teams are reviewing patient antimicrobials daily, then a patient may have their antimicrobials ceased when there is still an intention to treat. Contributors to this phenomena may include: time/resource constraints, an accidental oversight when reviewing a patient or teams not knowing that the antibiotic timeout function is utilized in CCLHD hospitals. While cessation of antimicrobials for patients who require them is a serious concern there have been no reported antibiotic timeouts which have resulted in any independently confirmed adverse outcomes for a patient in the CCLHD. Proposed mechanisms to address the potential risks include education during orientation for new clinical teams with intermittent reminders, an automated electronic task generated that prompts teams to review specific antimicrobials about to have the antibiotic timeout function employed, and regular auditing of Incident Information Management System (IIMS) reports regarding antibiotic timeouts.
Another potential negative impact of the hard stop functionality is so called “antibiotic timeout fatigue”. The primary purpose of the antibiotic timeout function is to prompt teams to review the appropriateness of antimicrobials periodically. One concern is that if prescribing clinicians are required to repeatedly represcribe antimicrobials they may develop an automated response to resprescribing antimicrobials ceased by the antibiotic timeout function without assessing appropriateness. Alert fatigue is a recurring concern across multiple health professions that utilize patient electronic notes and charts with several studies looking into solutions [23, 24]. Suggested initiatives include regular education regarding the purpose of the antibiotic timeout function and its demonstrated benefits, adopting a tiered alert system giving greater prominence to antimicrobials involved in more serious infections, junior medical officer feedback surveys at the end of each clinical rotation and antimicrobial stewardship teams to monitor for antimicrobials that may have been represcribed without mindful review.
The study has a number of limitations some of which have been outlined above. No direct comparison has been made between the post eMeds cohorts that include and do not include an antibiotic timeout function. As such the effect of the electronic prescribing system on antimicrobial prescribing is difficult to differentiate from the effect of the antibiotic timeout function. It is unclear to what extent changes in general antimicrobial prescribing trends between 2017 and 2019 may have influenced DOT and LOT. Further investigation would be helpful in order to draw further conclusions regarding the demonstrated reduction in DOT and LOT. Patients on concurrent antimicrobials for indications other that CAP or IECOPD treatment were included in the final DOT and LOT count. Whilst this may potentially be considered an effect modifier, antimicrobials were counted in this manner for both pre and post antibiotic timeout cohorts and is unlikely to influence any statistical or practical inferences.
Patients were selected from a pool generated by the restricted antimicrobial software Guidance MS®. Antimicrobials are in general more likely to be restricted and require registering on Guidance MS® if they are broad spectrum and higher risk. These antimicrobials are generally reserved for more severe or unusual infections and thus due to this selection method patients with mild CAP and/or IECOPD were not included. Inclusion of these patients may have revealed further insights into differences/similarities between the two groups. Adjusting the methodology to include patients prescribed non-restricted antimicrobials and those with mild CAP and IECOPD may be an area for future investigation.
A recurring limitation of many antimicrobial stewardship studies is the difficulty in measuring a tangible microbiological benefit. Evidence for the association between the use of antimicrobials and the rise in AMR is well described in laboratory, ecological and human studies at both the individual and population levels [25]. This requires long-term studies with extensive follow up that is outside the scope of this research. Whilst this study did not attempt demonstrate a direct correlation between reduced antimicrobial use and reduced rates of AMR, the existing literature is sufficient to suggest a strong association.