The Agency for Healthcare Research and Quality has released the Healthcare Cost and Utilization Project Nationwide Inpatient Sample, or NIS, featuring 2009 data. The NIS is the largest all-payer inpatient care database in the United States.

The NIS is nationally representative of all short-term, non-federal hospitals in the United States. It is drawn from the HCUP State Inpatient Databases, which include more than 95 percent of all discharges in the United States. The NIS includes all patients from each sampled hospital, regardless of payer–including persons covered by Medicare, Medicaid, private insurance and the uninsured.

The NIS contains data from 44 states and can be weighted to produce nationwide estimates, allowing researchers and policy makers to use the NIS to identify, track, and analyze national trends in health care utilization, access, charges, quality and outcomes. The vast size of the NIS enables analyses of infrequent conditions, uncommon treatments and special patient populations. 

As part of the HCUP database family, the NIS is considered by health services researchers to be one of the most reliable and affordable databases for studying important health care topics.

The 2009 NIS can be purchased through the HCUP Central Distributor and data can be accessed via HCUPnet, a free online query system. Additional information about the NIS and other HCUP products is located on the HCUP-US website.