Web search query volume as a measure of pharmaceutical utilization and changes in prescribing patterns.

BACKGROUND Monitoring prescription drug utilization is important for both drug safety and drug marketing purposes. However, access to utilization data is often expensive, limited and not timely. OBJECTIVES To demonstrate and validate the use of web search engine queries as a method for timely monitoring of drug utilization and changes in prescribing behaviors. METHODS Drug utilization time series were obtained from the Medical Expenditure Panel Survey and normalized search volume was obtained from Google Trends. Correlation between the series was estimated using a cross-correlation function. Changes in the search volume following knowledge events were detected using a cumulative sums changepoint method. RESULTS Search volume tracks closely with the utilization rates of several seasonal prescription drugs. Additionally, search volume exhibits changes following known major knowledge events, such as the publication of new information. CONCLUSIONS Search volume provides a first order approximation to pharmaceutical utilization in the community and can be used to detect changes in prescribing behavior.