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Length of Stay (LOS)

What is length of stay?

Length of stay (LOS) is a clinical metric that measures the time elapsed between a patient’s hospital admittance and discharge. LOS can be calculated on a hospital-wide basis or by therapy area, including acute myocardial infarctions (heart attacks) and diabetes. Numerous factors can contribute to a patient’s length of stay, including comorbidities, patient acuity or case mix, hospital quality performance, and provider staffing levels, among others.

What is the difference between patient days and length of stay?

Despite sounding similar, length of stay and patient days are measuring different metrics within a hospital. The main difference between them is that the length of stay refers to the average number of days a patient stays in the hospital per admission, while patient days refer to the total number of days all patients spend in a hospital during a specific period of time. For example, if the period is one week, the daily inpatient census is calculated for each day and summed together to find the total number of inpatient days for that week.

Dividing the number of inpatient days by the number of admissions or discharges at a facility within the specified time period is actually how you calculate a hospital’s average length of stay, indicating how similar the two metrics are.

Why is the length of stay an important metric in healthcare?

Length of stay data offers insights into care efficiency over time, including correlations between stay length and hospital-acquired conditions (HACs). Longer patient stays have been associated with an increased risk of hospital-acquired infections (HAIs) and higher mortality rates for some conditions.

A patient’s length of stay also affects a hospital’s financial performance—the longer a patient remains at a hospital, the more money the facility spends treating them. To reduce cost per discharge, CMS offers some financial incentives to reduce patient stay lengths per episode of care.