The Capacity to Care: Step-down or Intensive Units?

CHAN, Carri W. | GREEN, Linda V. | LEKWIJIT, Suparerk | 盧立建 | ESCOBAR, Gabriel

Step-down care units (SDUs) are a cost-effective way to treat patients referred from intensive care units (ICUs), but they could be failing patients admitted from emergency departments (EDs). In an important new study, HKUST’s Lijian Lu and co-researchers examine the effectiveness of SDUs and identify stark differences in patient outcomes. ED patients referred to SDUs are 50% more likely to be readmitted to hospital and 12% more likely to die in hospital. The findings of this paper hold clear lessons for care providers, especially those involved in managing different customer types.

Designed to relieve pressure on cash-strapped healthcare systems, SDUs play a critical role in healthcare services, treating those not sick enough to be treated in emergency departments but not stable enough for general wards. However, “there is a lack of consensus in the medical community surrounding the use of SDUs,” say the authors, as well as a lack of “substantive evidence concerning their effectiveness.” Their research began with a fundamental question: “Does admitting a patient to an SDU improve or degrade patient outcomes?”

To answer this question, the authors gathered patient data from 10 hospitals in Kaiser Permanente in California, U.S., comprising severity scores assigned by clinicians on arrival at SDUs. The data covered more than 165,000 hospitalizations over 1.5 years, allowing the researchers to comprehensively explore four key patient outcomes: mortality, length of stay, hospital and ICU readmission.

The authors found that discharge from an ICU to an SDU was “associated with improved patient outcomes.” Patients were 17% less likely to die in hospital and 18% less likely to be readmitted within two weeks. Increasing the capacity of SDUs (reducing what the authors describe as “busyness”) could significantly enhance patient outcomes, say the authors. “We estimate that eliminating SDU busyness would translate into annual savings of 187 lives, 3,096 hospital days, 128 (182) ICU readmissions in two (five) days, and 137 hospital readmissions in two weeks.”

Patients admitted to SDUs from EDs, however, face significant risks. “For high-severity patents, being admitted to the SDU appears to be associated with worse outcomes,” warn the authors. Such patients require continued emergency care and medical attention, which SDUs usually fail to supply—especially when operating at capacity. “Our results suggest that being admitted to the hospital when the SDU is busy is associated with substantial degradation in patient outcomes,” say the authors.

The study provides insights for healthcare providers into the importance of effective patient triage—along with a clear warning. To minimize risk, say the researchers, “a data-driven approach, such as the one taken in this paper, could be utilized to classify patients,” capitalizing on freely available demographic information. More broadly, the paper makes a valuable contribution to research on the “relative costs and benefits associated with serving different customer types by the different levels of service,” opening up exciting avenues for future studies of complex service settings.


Assistant Professor
Information Systems, Business Statistics & Operations Management