The Impact of Step-Down Unit Care on Patient Outcomes

Step Down Units (SDUs) were initially introduced in hospitals in order to provide an intermediate level of care for semi-critically ill patients who are not sick enough to require intensive care but not stable enough to be treated in the general medical/surgical ward. However, there is a lack of consensus within the medical community as to how these units should be used as well as the impact of SDU care on patient outcomes. Using data from 10 hospitals from a single hospital network, we use instrumental variable approaches to estimate the impact on patient outcomes of routing patients to the SDU from the Emergency Department (ED) as well as the Intensive Care Unit (ICU). Our empirical findings suggest that SDU care is associated with better clinical outcomes for some patients – reducing in-hospital mortality by 6%-20%, shortening hospital length-of-stay (LOS) by 0.5-1.08 days or reducing ICU readmission rate by 4% and hospital readmission rate by 8%. However, inappropriately admitting patients to the SDU is associated with an increase in mortality risk by 1.60% and hospital LOS by nearly a factor of 2. Our findings suggest that an SDU may be a costeffective way to treat patients when used as a true step down unit, i.e. for patients who are post-ICU. However, the impact of SDU care is more nuanced if and when other patients are admitted — for some patients, SDU admission is associated with substantial degradation of outcomes, while for others, it is associated with slightly improved outcomes.