Medicare Inpatient File, LDS or RIF: Counting Distinct Hospitalizations

The base segment of the Medicare Inpatient claims files (RIF and LDS) contains a record for each claim submitted by a hospital (facility) during a patient’s hospitalization. More than 99% of the inpatient stays generate only one facility claim[1],[2].  However, for those stays that generate multiple facility claims, ResDAC recommends researchers follow CMS’s method to group distinct hospitalizations[3], which is used to create the MedPAR file. They group claims by each unique combination of three elements:

1)  Patient identifier

• "Encrypted CCW Beneficiary ID" (BENE_ID) in Identifiable files

-or-

• “DESY SORT KEY” (DSYSRTKY) in Limited Data Set (LDS) files

2)  Admission date

• “Claim Admission Date” (CLM_ADMSN_DT or ADMSN_DT) in RIF and 2009 and forward LDS files [prior to 2009, LDS files contained QQYY only, so this was not possible]

3)  Provider Number (aka CMS Certification Number [CCN])

• “Provider Number” (PRVDR_NUM or PROVIDER) in both Identifiable and LDS files

RIF claims within a hospitalization may be sequenced by Claim From Date (CLM_FROM_DT or FROM_DT) and Claim Through Date (CLM_THRU_DT or THRU_DT), and within 2009 and forward LDS claims by Claim Through Date. In the last claim submitted, Claim Through Date will equal Discharge Date (NCH_BENE_DSCHRG_DT or DSCHRGDT).