STAY RECORDS FILES

A stay record summarizes all services rendered to a beneficiary from the time of admission to a facility through discharge. The only stay record data currently produced by CMS are contained in the MEDPAR File.

Medicare Provider Analysis and Review (MEDPAR) File

The MEDPAR File (commonly referred to as MEDPAR) contains inpatient hospital and SNF final action stay records. Each MEDPAR record represents a beneficiary stay in an inpatient hospital (where discharged) or in a SNF (may still be a patient.) Only inpatient records with discharge dates are included in MEDPAR; SNF records are included even if discharge data are not present because discharge information is not always received. These records are a major source of data for program analyses, evaluations, and utilization statistics.

File Creation

CWF claims records are processed weekly into the NCH Nearline Repository. Beginning in June 1995, the Inpatient and SNF claims from the NCH 100% Nearline File became the source of MEDPAR. (Prior to June 1995, MEDPAR was created from claims from the Medicare Quality Assurance System). Each month Inpatient and SNF claims are accumulated from the Nearline Repository. At the end of each quarter the monthly files are merged into a database that contains claims for the current and previous two years. The updated database is processed through the final action algorithms, and then split into two segments for each year. One segment contains all Inpatient claims with discharge dates and SNF claims with admission dates in January through September. The other segment contains claims with dates in October through December. This allows for the creation of fiscal year and calendar year files as needed.

Remaining claims are summarized to create a stay record. A match on claim number, admission date, and provider number creates a stay. These stay records are then used to create MEDPAR records.

File Maintenance

The MEDPAR files are created quarterly in March, June, September, and December. The claims records used to create MEDPAR are validated paid claims that have been processed by the NCH Medicare Quality Assurance System. No additional edits or validation are performed before the MEDPAR records are created. However, OIS QA initiatives have been directed at MEDPAR data to uncover any specific reliability and consistency problems with the data. Any data anomalies are addressed through warning indicators contained in the record. These indicators flag questionable data in each MEDPAR record.

From 1979 through 1983, MEDPAR contained stay data for a 20% sample of Medicare beneficiaries. These were calendar year files only. In 1984, MEDPAR was expanded to contain stay data for all beneficiaries. Annual MEDPAR files, identified by the file update date, are available for fiscal years and calendar years 1984 forward.

File Structure and Usage

MEDPAR records contain data from claims for services provided to Medicare beneficiaries admitted to Medicare-certified hospitals and SNFs. Each MEDPAR record may represent one claim or multiple claims, depending on the length of a beneficiary's stay and the amount of inpatient services used throughout the stay. Approximately 95% of inpatient stays and 50 % of SNF stays involve a single claim.

Both beneficiary HIC number and provider number are included on each record, making MEDPAR a valuable data resource for health care research and analyses that require beneficiary or facility-specific data. The database is sorted by HIC number, admission date, and provider number (all in ascending order) to enable an individual's stay records to be linked to study inpatient history and track patterns and outcomes of care over time. Beneficiary demographic characteristics, diagnosis and surgery information, and use of hospital or SNF resources are included on the MEDPAR records. In addition, the records contain detailed accommodation and departmental charge data, and days of care and entitlement data.

As of June 1995, MEDPAR records represent final action claims data in which all adjustments have been resolved. Prior to June 1995, a MEDPAR record represented an accumulation of adjustment claims. Therefore, the number of bills used to make up a stay will generally be one beginning with the June 1995 update, whereas it would have been several claims prior to June 1995.

MEDPAR has been used for research into chronic diseases prevalent in the elderly population such as cancer, heart disease, and diabetes. It has also been used to update annual hospital Prospective Payment System (PPS) rates.

Data Structure and Usage

Since it was first developed, MEDPAR has been enhanced to accommodate the increasing level of detail required on the claims submitted by providers. The claims, and in turn MEDPAR, include detail regarding accommodations, services, and costs associated with each inpatient stay at a hospital or SNF. The inclusion of this information was critical for the implementation of PPS, and also supplied policy analysts and researchers with data to track patterns and outcomes of care provided to Medicare beneficiaries.

MEDPAR is available in an enhanced 500 character, fixed-length record format for fiscal and calendar years 1987 to the present. As of March 1999, a 514 character, fixed-length record format was created to accommodate Y2K date field expansions. In March 2000, the 500 character MEDPAR will no longer be available. Fiscal and calendar years 1984 to 1986 are available in abbreviated formats. Accommodation data and service data fields have been enhanced to provide additional detail on specific types of hospital resources used (e.g., whether a stay was in a private or semi-private room in an intensive care or coronary care ward; or whether coronary care was provided for myocardial infarction or pulmonary care). In addition, new fields contain warning indicators which flag claims with questionable data, such as multiple claims with missing interim claims, a zero or negative payment or total charges, or a date of death earlier than date of admission.

The 1997 MEDPAR File contains approximately 14 million records: 12 million hospital records and 2 million SNF records.

Methods of Access

Access to MEDPAR is restricted because it contains patient identifiers. However, three BEFs with patient identifiers are maintained:

• the Expanded Modified MEDPAR-Hospital File (National)
• the Expanded Modified MEDPAR Hospital File (State - a subset of the national data extracted by provider state or beneficiary state of residence)
• the Expanded Modified MEDPAR-SNF File

Further information about these BEFs can be found in the Beneficiary Encrypted Files Data chapter.

Migration of Data

Prior to the CWF, MEDPAR was created from bill records. Since the adoption of the CWF, MEDPAR is created from CWF claims records processed through the NCH Medicare Quality Assurance System. As of June 1995, MEDPAR is created from the NCH 100% Nearline File inpatient/SNF claims records processed through final action algorithms.

List of Data Elements

The list of data elements to be included on the CMS web site (www.cms.hhs.gov) for MEDPAR will reflect the current, expanded version of the full MEDPAR File in its 500 character record format (6/95 format.) MEDPAR files created in earlier years contain less detailed information and a smaller number of variables per record.