• Medicare;
  • active drug safety surveillance;
  • real-time safety evaluation;
  • claims adjudication;
  • administrative claims data



The Centers for Medicare & Medicaid Services claims comprise an administrative database of beneficiary-specific clinical information. This study evaluates the impacts of (i) claim information updates (claims adjudication) and (ii) delay in claim processing (claims delay) on real-time evaluation of health service and drug safety signals using the Medicare database.


Using Medicare claims data accumulated through May 2009 on health services rendered in 2006 and drugs dispensed in 2007, this study measures the frequency with which clinical information changes in the database as a result of (i) claims adjudication and (ii) claims delay.


Over 85% of health services claims were processed within 8 weeks after the date of service, and 72% of drug claims were processed within 3 months after the dispense date. Clinical information changed for no more than 3% of unique claim groups in inpatient hospital, outpatient institutional, physician's office, and prescription drug Medicare claim settings.


Claims delay is consistent across time and is minimal. Claims adjudication does not substantially impact the content of clinical information in the Medicare claims database. Therefore, the Medicare claims database provides consistent information regarding health services and prescription drugs in a manner that is prompt enough to facilitate medical product safety evaluations in real time. Copyright © 2011 John Wiley & Sons, Ltd.