A Framework for Leveraging “Big Data” to Advance Epidemiology and Improve Quality: Design of the VA Colonoscopy Collaborative

Abstract

Objective:To describe a framework for leveraging big data for research and quality improvement purposes and demonstrate implementation of the framework for design of the Department of Veterans Affairs (VA) Colonoscopy Collaborative.Methods:We propose that research utilizing large-scale electronic health records (EHRs) can be approached in a 4 step framework: 1) Identify data sources required to answer research question; 2) Determine whether variables are available as structured or free-text data; 3) Utilize a rigorous approach to refine variables and assess data quality; 4) Create the analytic dataset and perform analyses. We describe implementation of the framework as part of the VA Colonoscopy Collaborative, which aims to leverage big data to 1) prospectively measure and report colonoscopy quality and 2) develop and validate a risk prediction model for colorectal cancer (CRC) and high-risk polyps.Results:Examples of implementation of the 4 step framework are provided. To date, we have identified 2,337,171 Veterans who have undergone colonoscopy between 1999 and 2014. Median age was 62 years, and 4.6 percent (n = 106,860) were female. We estimated that 2.6 percent (n = 60,517) had CRC diagnosed at baseline. An additional 1 percent (n = 24,483) had a new ICD-9 code-based diagnosis of CRC on follow up.Conclusion:We hope our framework may contribute to the dialogue on best practices to ensure high quality epidemiologic and quality improvement work. As a result of implementation of the framework, the VA Colonoscopy Collaborative holds great promise for 1) quantifying and providing novel understandings of colonoscopy outcomes, and 2) building a robust approach for nationwide VA colonoscopy quality reporting.

Risk factors for colorectal cancer significantly vary by anatomic site

“…Controls were veterans with no prior CRC diagnosis, normal baseline colonoscopy defined by presence of a CPT code for diagnostic colonoscopy only (45378 or G0121), and absence of a colon biopsy (as evidenced by absence of a pathology report within 30 days of baseline colonoscopy) (see online supplementary appendix table C for full outline of study selection criteria). Our prior work has shown that this approach is 96.3% sensitive and 97.5% specific for normal colonoscopy and had a positive predictive value of 97% 12 13. Additionally, to avoid inclusion of controls with missed CRC at baseline colonoscopy, controls with CRC diagnosed by VACCR or an ICD-9 code within up to 3 years of baseline colonoscopy were excluded.…”

Metformin Is Associated With Reduced Odds for Colorectal Cancer Among Persons With Diabetes

“…Controls were Veterans with normal index colonoscopy defined by presence of a Current Procedural Terminology code for diagnostic colonoscopy only (45378 or G0121) and absence of a pathology report (within 30 days of index colonoscopy). Our previous work has shown that this definition is 96.3% sensitive and 97.5% specific for normal colonoscopy and had a positive predictive value for identifying individuals with normal colonoscopy of 97% (15,16). To avoid inclusion of controls with missed CRC at baseline colonoscopy, controls with CRC diagnosed by the VACCR or International Classification of Diseases, Ninth Revision code within up to 3 years of index colonoscopy were excluded.…”

“…To avoid inclusion of controls with missed CRC at baseline colonoscopy, controls with CRC diagnosed by the VACCR or International Classification of Diseases, Ninth Revision code within up to 3 years of index colonoscopy were excluded. If a candidate control had less than 3 years of follow-up (due to death or loss to follow-up at VA) based on the Veterans Health Administration Vital Status File, he/she was excluded (15).…”

Ascertainment of Aspirin Exposure Using Structured and Unstructured Large-scale Electronic Health Record Data

“…Our overarching aim was to develop and validate a strategy for identifying aspirin exposure within our use case of Veterans who underwent usual care colonoscopy within the Department of Veterans Affairs (VA). The cohort was created as part of a VA Office of Research and Development-funded study to examine predictors of colorectal cancer and high-risk polyps after baseline adenoma removal 19. As exposure may impact colorectal cancer risk, we sought to identify a rigorous method for aspirin ascertainment.…”