Impact of outlier status on critical care patient outcomes: Does boarding medical intensive care unit patients make a difference?

Purpose: To evaluate the impact of outlier status, or the practice of boarding ICU patients in distant critical care units, on clinical and utilization outcomes. Materials and methods: Retrospective observational study of all consecutive admissions to the MICU service between April 1, 2014-January 3, 2016, at an urban university hospital. Results: Of 1931 patients, 117 were outliers (6.1%) for the entire duration of their ICU stay. In adjusted analyses, there was no association between outlier status and hospital (OR 1.21, 95% CI 0.72–2.05, p = 0.47) or ICU mortality (OR 1.20, 95% CI 0.64–2.25, p = 0.57). Outliers had shorter hospital and ICU lengths of stay (LOS) in addition to fewer ventilator days. Crossover patients who had variable outlier exposure also had no increase in hospital (OR 1.61; 95% CI 0.80–3.23; p = 0.18) or ICU mortality (OR 1.05; 95% CI 0.43–2.54; p = 0.92) after risk-adjustment. Conclusions: Boarding of MICU patients in distant units during times of bed nonavailability does not negatively influence patient mortality or LOS. Increased hospital and ventilator utilization observed among non-outliers in the home unit may be attributable, at least in part, to differences in patient characteristics. Prospective investigation into the practice of ICU boarding will provide further confirmation of its safety.