Evaluation of the Estimated Number of Influenza Patients from National Sentinel Surveillance using National Database of Electronic Medical Claims

Abstract

Officially, the number of influenza patients nationwide has been estimated from the national official sentinel surveillance of infectious diseases (NOSSID), which is based on the Law Concerning the Prevention of Infectious Diseases and Medical Care for Patients of Infections (the Infectious Diseases Control Law). Prescription Surveillance (PS) has also provided a numerical estimate of influenza patients. This study compared these two estimations using NOSSID and PS with the numbers of influenza patients from all electronic medical claims (NDBEMC), which are nearly comprehensive data from surveys. Results show that the estimate from NOSSID was about twice the estimate from NDBEMC. However, the estimated number from PS was almost equivalent to that from NDBEMC. The estimated number of patients from NOSSID might not be precise, but NOSSID itself is expected to be useful to monitor influenza trends.