Are medical outliers associated with worse patient outcomes? An analysis of routinely collected data within a regional NHS hospital

Background/objectives: Faced with ever increasing pressures, hospital bed managers often resort to placing patients on wards that are not designed for the type of care the patient requires. Evidence associating medical outliers, as these cases are often called, with patient outcomes are scarce. Anecdotal evidence and small scale studies point towards a range of negative impacts on patient outcomes and experience. The aim of this research is to explore the quality and safety of patients’ healthcare provision by identifying whether being a medical outlier is associated with worse patient outcomes.
Methods: This is a retrospective cross-sectional observational study. Secondary data from the Patient Administration System of a district general hospital were provided for the financial years 2013/14-2015/16. The data included 71,038 medical patient spells for the three year period. Univariate analysis was used to investigate any potential association and multivariate logistic regression and zero truncated negative binomial regression were used to explore patient outcomes (in-hospital mortality, 30-day mortality, readmissions and length of stay) while adjusting for several confounding factors
Results: Univariate analysis indicated that an outlying medical in-hospital patient has higher odds for readmission, double the odds of staying longer in the hospital but not significant difference in the odds of in-hospital and 30-day mortality. Multivariate analysis indicates that being a medical outlier does not affect mortality outcomes or re-admission but is associated with longer length of stay in hospital.
Implications: This is the first quantitative study in England’s NHS that has sought to investigate potential associations between medical outliers and patient outcomes. After adjusting for other factors, medical outliers are associated with an increased LOS while mortality or re-admissions are not worse than patients treated in appropriate specialty wards. This is in line with existing, but limited literature that such patients experience worse patient outcomes. Hospitals may need to revisit their policies regarding outlying patients since increased length of stay is associated with an increased likelihood of harm events, worse quality of care and increased healthcare costs.