Medicare claims data as public use files: a new tool for public health surveillance.

Claims data are an important source of data for public health surveillance but have not been widely used in the United States because of concern with personally identifiable health information and other issues. We describe the development and availability of a new set of public use files created using de-identified health care claims for fee-for-service Medicare beneficiaries, including individuals 65 years and older and individuals with disabilities younger than 65 years, and their application as tools for public health surveillance. We provide an overview of these files and their attributes; a review of beneficiary de-identification procedures and implications for analysis; a summary of advantages and limitations for use of the public use files for surveillance, alone and in combination with other data sources; and discussion and examples of their application for public health surveillance using examples that address chronic conditions monitoring, hospital readmissions, and prevalence and expenditures in diabetes care.