The HCUP national inpatient sample (NIS) is comprised of a 100 percent claims for inpatient discharges occurring during 1998 in a nationally representative sample of about 20 percent of the hospitals in 24 states. In total, there are 984 community hospitals stratified on five characteristics: ownership/control, bed size, teaching status, urban/rural location, and region. Not all states allow individual hospital identifiers to be released. We were able to link the NIS to only 640 hospitals located in states for which we have Medicare cost reports and hospital-specific information on Medicaid DSH payments. These hospitals are located in 15 states: AZ, CA, CO, CN, FL, IL, IO, MA, MD, MO, NJ, NY, UT, WA and WI. We dropped Pennsylvania hospitals because of the lack of hospital-identifiable Medicaid DSH data. We estimated what Medicare DSH payments would be for Maryland hospitals in the absence of the waiver and retained them in our simulation.
The NIS includes uniform categories for the expected primary payer:
- Medicare (both fee-for-service and managed care patients)
- Medicaid (both fee-for-service and managed care patients)
- Private insurance
- No-charge (includes charity care)
The "other" payer category includes patients covered by CHAMPUS, Workmen's Compensation, Title V and other government programs. These categories were previously broken out but discontinued in the 1998 data because of problems in coding the data uniformly across states. As explained below, we use the 1997 data to develop an estimate of patients covered by local indigent care programs. Compared to the national estimates (Table 7.1), our HCUP/DSH analysis file has a lower percentage of discharges and days where Medicaid is the expected primary payer (Table 7.1). Additionally, the percentage of Medicare days is considerably higher. The statistics for the uninsured (self-pay) are quite similar to the national average.
|NIS Weighted National Estimate*||Hospitals in HCUP/DSH Database|
|Payer||% Discharges||% Days||Mean Length of Stay||Mean Charge
|% Discharges||% Days||Mean Length of Stay||Mean Charge ($)|
*Weighted national estimates from HCUP Nationwide Inpatient Sample (NIS), 1998, Agency for Healthcare Research and Quality (AHRQ), based on data collected by individual states and provided to AHRQ by the states. Total number of weighted discharges in the U.S. based on HCUP NIS = 34,874,001. Note that no significance testing for differences is provided.