Question: In the CMS DRG datasheet, what is the difference between the column titled “Geometric Mean LOS” and the one labeled “Arithmetic Mean LOS”?
Answer: The geometric mean length of stay or (GMLOS) is the national mean length of stay for each diagnostic related grouper (DRG) as determined and published by CMS. The arithmetic mean length of stay (ALOS) is the average length of stay experienced by a patient within a chosen DRG. The geometric mean reduces the effect of very high or low values, which might bias the mean if a straight average (arithmetic mean) is used.
Hospitals can use GMLOS and ALOS to analyze reimbursement impacting areas. For instance, a hospital analyst could collect their hospital’s ALOS for hospital inpatients in a particular DRG admitted on a particular day of the week to the GMLOS. Variations in the length of stay relative to the day of the week that a patient was admitted can identify days that the hospital is receiving less reimbursement for stays that go over the GMLOS. The analyst can then look for possible patterns or downfalls (for instance patients admitted on Friday have a longer LOS due to lack of testing over the weekend). In addition, patient charts can be identified that have longer GMLOS for a DRG to see if conditions were missed that would equate to a higher reimbursing DRG.
Inpatient coders can get DRG stats in SuperCoder.com’s MS-DRG Master.
