Differentiating direct from indirect admissions based solely on where the patient was initially admitted may introduce bias if no criterion is specified for the upper limit of the interval between arrival at the ED and admission to the Wortmannin ATM MICU/HDU.

There is no universally accepted duration which determines that a patient’s condition is not expected to deteriorate to a point that transfer to the MICU/HDU becomes necessary soon after admission to the general ward. However, for this study, the 24 h upper limit from ED presentation to MICU/HDU admission was used as it was considered a reasonable interval during which a non-critical patient admitted to the general ward is expected to remain stable. In the multivariate analysis, MICU and HDU patients were analysed as a single group as analysing them separately would have substantially reduced the sample size. While the magnitude of effects may differ between the two groups, bivariate results suggested similar directions of effect for MICU and HDU patients analysed separately. This study validates previously published findings that indirect ICU admissions or delays lead to adverse patient outcomes. While the direction of effect may be consistent across settings, variations in the magnitude

of effect may be affected by factors such as differences in ICU bed capacity, the profile of patients served, organisational procedures and standards, as well as physician characteristics. For this reason, the estimated risk of adverse outcomes in one setting will not necessarily apply to another, thus highlighting the usefulness of conducting similar studies in one’s own context. These self-assessments enable emergency and ICU departments to customise improvements based on their unique situations. It also facilitates performance

monitoring by providing a baseline measure of the adverse consequences of indirect admissions, against which future results may be compared. Supplementary Material Author’s manuscript: Click here to view.(1.2M, pdf) Reviewer comments: Click here to view.(144K, pdf) Footnotes Contributors: ES, BHH and BH conceived the study. ES and BH facilitated and provided access to the data. All the authors designed the study. JADM and WFC designed and supervised data collection. Batimastat JADM supervised data management and quality control and also analysed the data and drafted the manuscript. ES and BHH monitored the study’s progress. All authors provided peer review and substantial inputs to the final form of the manuscript. Funding: This study was internally funded by the Emergency Department, Tan Tock Seng Hospital. Competing interests: None. Ethics approval: The research was approved by the Domain Specific Review Board of the National Healthcare Group (Singapore) Provenance and peer review: Not commissioned; externally peer reviewed. Data sharing statement: No additional data are available.