Clinical Care

New calculation helps determine length of stay

The geometric mean length of stay takes into account the patient’s diagnosis when estimating discharge dates.



Inpatient providers and staff will see a new number on the patient’s Epic story board beginning Nov. 14. The geometric mean length of stay, or GMLOS, represents the typical stay for patients diagnosed with heart failure, COPD, cellulitis, pneumonia and other diagnostic related groups as determined by CMS.

Measuring the GMLOS reduces the effect of very high or low values experienced with average length of stay. A DRG 193 (simple pneumonia and pleurisy w/MCC) has a GMLOS number of 4.0. Likewise, a DRG 329 (Maj small and large bowel proc. w/MCC) has a GMLOS of 9.8.

See GMLOS tip sheet »

These numbers allow clinicians to benchmark length of stay so they can make informed decisions about the patient’s expected date of discharge. Each DRG has a geometric mean length of stay. The number is created when provider notes are read electronically from CDI, and coding modules and DRGs are assigned. Those DRGs are compared against published average-length-of-stay and DRG data to provide a customized GMLOS for each inpatient health record.

The GMLOS will change twice daily at 6 a.m. and 4 p.m., seven days a week.

Bedside staff should view GMLOS as a benchmark to be considered with estimated date of discharge. Note that the EDD may capture variables about the patient that are not reflected in the GMLOS. Both values should be considered when working with the patient’s family and the care team to plan and track discharge goals.

Tags: EDD, estimated date of discharge, geometric mean length of stay, GMLOS, Holly Nickerson, STAT
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If you have a question, please contact the author or relevant department directly.

2 Comments. Leave new

  • Dr. Mike Marvinny
    November 8, 2023 5:57 am

    Hi. When calculating the GMLOS for a specific GRG, are you comparing geometric mean to ALOS or the system GMLOS for the same DRG? Since the GMLOS is a calculation the takes population data from CMS, the “n” for
    Those (CMS) data sets will be much larger than what we have in the Asante system and will being you closer to the mean. If we are comparing GMLOS to ALOS, the outliers in the ALOS data will always screw the data to a higher LOS further from the geometric mean. In other words, in any two similar data sets calculated to a geometric mean or average, the average will be greater than the geometric mean.

    • Steven Hersch MD
      November 10, 2023 4:33 pm

      Great question! We will be posting the GMLOS that corresponds to the best current DRG for a patient, based on nationwide data from CMS. We specifically chose GMLOS because it minimizes the impact of outliers (unusually long or unusually short LOS).


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