get_inpatient_admissions: extract data from the inpatient admissions table
In xbsd/rxdsapi2: API for RXDS KDB+ Applications

Description Usage Arguments Details Value Examples

The inpatient_admissions family of functions (get_inpatient_admissions) provides an interface to query the inpatient_admissions table in the Truven Marketscan Health Research Database. The get_inpatient_admissions function extracts data verbatim from the inpatient_admissions table. The get_patient_id_inpatient_admissions function extracts the index date (i.e., the first date of service) corresponding to patient ids (generally the 'enrolid') within the given date range and if applicable, optional parameters.

get_inpatient_admissions(optional_q_table_name = "inpatient_admissions",
  columns_to_return, start, end, optional_diag_codes = "__NULL__",
  optional_proc_codes = "__NULL__", optional_enrolids = "__NULL__",
  api_function = "get_inpatient_admissions", return_all_flag = F, ...)


  get_patient_id_inpatient_admissions(optional_q_table_name = "inpatient_admissions",
  start, end, optional_diag_codes = "__NULL__",
  optional_proc_codes = "__NULL__", optional_enrolids = "__NULL__", ...)

`optional_q_table_name`	an optional field where the name of the inpatient_admissions table may be passed. The function sets a default table name called "inpatient_admissions" which is used when the user does not provide a table name
`columns_to_return`	a character vector of columns names corresponding to the names of the table headers (columns) in the inpatient services table.
`start`	the start date for the query. This should be of the form yyyy.mm.dd and must be passed as a character. For example, to pass June 30, 2017, the value of the start parameter should be "2017.06.30"
`end`	the end date for the query. This should be of the form yyyy.mm.dd and must be passed as a character. For example, to pass Nov. 30, 2017, the value of the start parameter should be "2017.11.30"
`optional_diag_codes`	a character vector of dx (diagnosis) codes
`optional_proc_codes`	a character vector of proc1 (procedure) codes
`optional_enrolids`	an integer vector of enrolid values
`api_function`	a variable indicating the name of the function. It is unlikely that you'll ever need to change the value of this parameter and it is best left as-is
`return_all_flag`	a boolean value indicating whether all the data should be returned to R. This parameter generally defaults to FALSE since returning large amounts of data to the R Session may take time. It should be set to TRUE only if you are certain that you'd like to load all the data that is a result of the query into your session.
`get_stats`	a boolean variable indicating whether query statistics should be printed

The inpatient_admissions functions allow the user to retrieve data from the inpatient_admissions table in the Truven Health MarketScan® Research Database.

The Inpatient Admissions dataset is part of the Truven Health Marketscan's Commercial Claims & Encounters database and contains claims information for services provided during a hospital admission. The table provides information on treatment during admissions such as diagnosis codes, procedure codes and other variables. It also contains detailed patient-level demographic data such as age, gender, employment-related information and others on a per-record basis.

Additional information from Truven: Truven Health constructs this table after identifying all of the encounters or claims (service records) associated with an admission (e.g., hospital claims, physician claims, surgeon claims, and claims from independent laboratories). Facility and professional payment information is then summarized for all services. The summarized information is stored in an admission record in the Inpatient Admissions Table.

The admission record also includes data that can only be identified after all claims for an admission have been identified. These additional data include the principal procedure, principal diagnosis, major diagnostic category (MDC), and diagnosis-related group (DRG). Truven Health uses the Centers for Medicare & Medicaid Services (CMS) DRG Grouper to assign an MDC and DRG to the admission record. In addition to the principal procedure and diagnosis codes, the admission record includes all diagnoses and procedures (up to 14 each) found on the service records that make up the admission. These additional codes (Diagnosis 2 through Diagnosis 15 and Procedure 2 through Procedure 15) are assigned chronologically based on service dates and do not duplicate the principal code. To be considered an admission, the grouping of these service records must meet certain criteria (e.g., a room and board claim must be present). If these criteria are not met, the records are stored in the Outpatient Services Table (O) and no admission record is created.

A data.table with the results of the query

# extract data from inpatient_admissions table

# extract dstatus, patflag, enrolid, admdate and proc1 from inpatient_admissions between
# svcdates 2009.03.20 and 2009.04.20 for diagnosis (dx) codes c("78650","7384"), procedure
# (proc1) codes c("8856","3971") and do not filter on optional_enrolids (set to __NULL__
# is the same as not setting it at all in a function. Here it is shown with the
# parameter set to __NULL)

get_inpatient_admissions(columns_to_return=c("dstatus","patflag","enrolid","admdate","proc1"),
start="2009.03.20",end="2009.04.20",optional_diag_codes=c("78650","7384"),optional_proc_codes=
c("8856","3971"), optional_enrolids="__NULL__", return_all_flag = F,get_stats="TRUE")

# extract first svcdate (the indexdate) from inpatient_admissions for all patients between
# 2009.03.20 and 2009.07.20 with diagnosis (dx) codes c("78650","7384") and procedure (proc1)
# codes of c("8856","3971")

get_patient_id_inpatient_admissions(start="2009.03.20",end="2009.07.20",optional_diag_codes=
c("78650","7384"), optional_proc_codes=c("8856","3971"),get_stats="TRUE")