Gaining Access to the Databases

The CPO has many national and local databases available for use with collaborators, including the State Inpatient Database (SID), Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality; National Inpatient Sample (NIS), Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality; the Multicenter Perioperative Outcomes Group (MPOG); the National Anesthesia Clinical Outcomes Registry (NACOR), developed and maintained by the Anesthesia Quality Institute (AQI); and the American College of Surgeons National Surgical Quality Improvement Program; and local data.

Each database contains different information; the data source needs to be chosen carefully to best answer study objectives. To conduct a study, each database has unique requirements; therefore, interested investigators need to work closely with CPO staff to adhere to data use agreements and select the most appropriate data source. Inquiries may be sent to Below are specific sections for each data source to explain the database and the requirements.


What is HCUP?

As described by the official website, "The Healthcare Cost and Utilization Project (HCUP) is a family of databases and related software tools and products developed through a Federal-State-Industry partnership and sponsored by AHRQ. HCUP databases are derived from administrative data and contain encounter-level, clinical and non-clinical information, including all listed diagnoses and procedures, discharge status, patient demographics, and charges for all patients, regardless of payer (e.g., Medicare, Medicaid, private insurance, uninsured)." More information regarding HCUP may be found here. The CPO has access to two datasets maintained by HCUP, the Nationwide Inpatient Sample and the State Inpatient Database. 

What is the difference between NIS and SID?

There are important differences between these two databases and depending on the research hypothesis, one database may be preferable to the other.

The NIS is the largest publicly available, all-payer inpatient database in the United States. Encompassing data from over a thousand hospitals, the database records approximately eight million hospital stays per year. Furthermore, methods may be employed to gain national weighted estimates to be analyzed. In total, NIS comprises a stratified sample for nearly 20% of US community hospitals. The NIS database is de-identified and contains patient and hospital demographics, and information pertaining to billing, diagnostics, and procedures. Additional information regarding NIS may be found here.  

The SID contains approximately 97% of all inpatient discharge records from community hospitals. Medicare, Medicaid, privately insured, and uninsured patients are all included. The database is widely used by researchers and policymakers to compare data, conduct market research, and analyze trends in healthcare utilization and outcomes. It contains more than one hundred clinical and non-clinical variables, such as principal and secondary diagnoses and procedures, admission and discharge status, patient demographics, total charge, and length of stay, with built-in safeguards to prevent identification of any particular patient, provider, or hospital. Additionally, a researcher can analyze the data to identify readmissions. Additional information regarding SID may be found here

How can I access NIS and SID data?

In order for investigators in the Department of Anesthesiology at Weill Cornell Medical College to use data from HCUP, some steps are necessary. Working with CPO staff, a project description must be completed and sent to HCUP for approval. In addition, the researcher must read and sign a Data Use Agreement (SID; NIS) and take the HCUP DUA Training Course. All documents must be provided to CPO staff for review and submission. 

What projects have been done using NIS and SID? 

A list of projects may be found at HCUP's website


What is NACOR?

The National Anesthesia Clinical Outcomes Registry (NACOR) of the Anesthesia Quality Institute (AQI) is the largest national anesthesia database available. NACOR is a voluntary data submission registry with the goal of facilitating the evaluation of quality in anesthesia care both locally and nationally. The registry is available to anesthesia providers in the US and represents an opportunity to survey data from all provider types, from private practices to large-scale hospitals. The spectrum advantageously provides a glimpse into many sections of anesthetic care. The AQI database is de-identified and contains patient demographics, billing, procedural, diagnostic, and provider information. For additional information regarding NACOR please visit

How can I access NACOR data?

In order for investigators in the Department of Anesthesiology at Weill Cornell Medical College to analyze data from NACOR, they must speak with CPO staff.

What projects can be completed using NACOR data?

As an example, CPO staff has recently published an article using NACOR data investigating the variability in anesthetic techniques for total knee arthroplasty: 

Fleischut PM, Eskreis-Winkler, J, Gaber-Baylis L, Giambrone, GP, Faggiani SL, Dutton, RP, Memtsoudis SG. Variability in anesthetic care for total knee arthroplasty using the AQI/NACOR data registry. AJMQ. 2014; 1-8.

CPO staff will assist interested investigators with identifying possible research projects using NACOR data.


What is MPOG?

Formed in 2008, the Multicenter Perioperative Outcomes Group (MPOG) is a consortium of several medical centers aggregating large volumes of observational inpatient electronic health record (EHR) data and patient-reported outcomes. MPOG has already extracted, transformed, and mapped more than two million patient records from various medical centers across the US and Europe. MPOG contains demographic information, basic case information, and pre, intra, postoperative documentation, as well as hospital discharge codes and charges. More information regarding MPOG may be found here

How can I access MPOG data?

Investigators in the Department of Anesthesiology at Weill Cornell Medical College should speak with CPO staff regarding the submission of a proposal to use MPOG data. 

To maintain a high standard of quality, MPOG has set specific processes in place prior to the distribution of study data. A proposal must be submitted by the researcher and approved by an MPOG committee. Detailed instructions related to the submission of a proposal may be found here

What projects have been done using MPOG?

A list of projects may be found at MPOG's website

Local Data Sources

What local data sources are available to Weill Cornell Medical College researchers?

The Department of Anesthesiology, in partnership with the Architecture for Research Computing in Health (ARCH) of the Department of Research Computing has partnered to create a Research Data Repository (RDR) to assemble pre, intra, and postoperative data in a single location. This RDR will allow for easier access to various pieces of information (demographic, clinical, provider, and outcomes information) necessary to answer clinical and outcome-based hypotheses.

How can I access the RDR?

An internal process has been created to manage requests for data from the RDR. In order for a Department of Anesthesiology researcher to gain access to data from the RDR, the researcher must first follow department protocol and vet their research question through the Director of Clinical Research. Once approved, the researcher must develop a scientific protocol and submit it for review to the Clinical Study Evaluation Committee (CSEC) and the Institutional Review Board (IRB). Once approval is gained from these governing bodies, the governance committee in the Department of Anesthesiology will review study documents and approve the transfer of data. Questions related to this process should be sent to CPO staff or the Clinical Research Team. 

Center for Perioperative Outcomes
NewYork-Presbyterian Hospital 
Weill Cornell Medical Center
428 East 72nd Street, Suite 800A
New York, NY 10021