Kid

KIDS Impatient Database

Last Updated Oct 6, 2008 03:02 PM

Introduction
The Kids' Inpatient Database (KID) is one of a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP), a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality.

The KID is a unique and powerful database of hospital inpatient stays for children. The KID development team designed the database to permit researchers to study a broad range of conditions and procedures related to hospitalizations of children. Researchers and policymakers can use the KID to identify, track, and analyze national trends in hospital utilization, access, charges, quality, and outcomes for children.

The KID is a nationwide sample of pediatric discharges from HCUP State Inpatient Databases (SID) community, non-rehabilitation hospitals weighted to all pediatric discharges in the target universe. The target universe includes all pediatric discharges from community hospitals in the United States that were open during any part of the calendar year. Beginning with the 2000 KID, rehabilitation hospitals were excluded from the universe because the type of care provided and the characteristics of the discharges from these facilities were markedly different from other short-term hospitals.

This report describes the 2000 KID sample design and summarizes the sample contents. Sample weights were developed to obtain national estimates of inpatient parameters. These weights are described in detail. The previous KID release contained data for calendar year 1997. Cumulative information is presented for both 1997 and 2000 to provide a longitudinal view of the database.

Sample Design
Design Considerations
The overall design objective was to select a sample of pediatric discharges that accurately represents the target universe, which includes discharges outside the frame (with zero probability of selection). Moreover, this sample was to be geographically dispersed, yet drawn only from data supplied by HCUP State Partners.

It should be possible, for example, to estimate DRG-specific average lengths of stay across all U.S. hospitals using weighted average lengths of stay, based on averages or regression coefficients calculated from the KID. Ideally, relationships among outcomes and their correlates calculated from the KID should hold across all U.S. hospitals. However, since the 2000 KID includes data from only 27 HCUP State Partners, some estimates may differ from the U.S. When possible, estimates based on the KID should be checked against national benchmarks, such as the National Hospital Discharge Survey, to determine the appropriateness of the KID for specific analyses. (Refer to the report HCUP Kids’ Inpatient Database Comparative Analysis, 1997, which is available on the 1997 KID Documentation CD-ROM and on the HCUP Website at http://www.ahrq.gov/data/hcup/.)

Sampling Frame
The KID sampling frame included all pediatric discharges from community, non-rehabilitation hospitals in the HCUP State Inpatient Databases (SID) that could be matched to the corresponding AHA survey data (subject to state-specific restrictions). For the 2000 KID, pediatric discharges were defined as having an age at admission of 20 or less. This is a change from the 1997 KID which included discharges with an admission age of 18 or less. Discharges with missing, invalid, or inconsistent ages were excluded.

Sampling Procedure
Unlike the Nationwide Inpatient Sample (NIS), the KID development team did not execute a two-stage sampling procedure. Instead, the KID includes a sample of pediatric discharges from all hospitals in the sampling frame. For the sampling, we stratified the pediatric discharges by uncomplicated in-hospital birth, complicated in-hospital birth, and pediatric non-birth. To further ensure an accurate representation of each hospital’s pediatric case-mix, we also sorted the discharges by state, hospital, DRG, and a random number within each DRG. We then used systematic random sampling to select 10 percent of uncomplicated in-hospital births and 80 percent of other pediatric cases from each frame hospital.

Discharge Weights
To obtain national estimates, we developed discharge weights using the AHA universe as the standard. For the weights, we post-stratified hospitals on six characteristics contained in the AHA hospital files. These were the same characteristics used to define the NIS sampling strata, with the addition of an additional stratum for freestanding children’s hospitals. Some of the NIS strata definitions were revised for 1998 and subsequent data years, and the 2000 KID used these revised strata. Hospital stratification variables were defined as follows:

See also Kid 597 1 - 5