Economic impact of respiratory syncytial virus-related illness in the US: an analysis of national databases.

To determine the impact of respiratory syncytial virus (RSV) infection on healthcare resource use and costs in the US from the third-party payer perspective. The study retrospectively analysed cross-sectional medical encounter data from three federally funded databases that comprise nationally representative samples of hospital inpatient stays, physician office visits and visits to hospital outpatient departments and emergency rooms. Identification of RSV infection-related medical encounters was based on the occurrence of RSV-specific International Classification of Diseases (9th Edition)-Clinical Modification diagnosis codes (079.6, 466.11, 480.1) as principal discharge diagnoses or the assumption that 10-15% of all otitis media visits were due to RSV infection. Outpatient drug costs were estimated based on average wholesale price, and physician fees and test/procedure costs were estimated based on prevailing national fees. Inpatient costs were estimated from total billed charges using a cost-to-charge ratio of 0.53. In 2000, nearly 98% of RSV infection-related hospitalisations occurred in children <5 years old. There were approximately 86,000 hospitalisations, 1.7 million office visits, 402 000 emergency room visits and 236,000 hospital outpatient visits for children <5 years old that were attributable to RSV infection. Total annual direct medical costs for all RSV infection-related hospitalisations ($US394 million) and other medical encounters ($US258 million) for children <5 years old were estimated at $US652 million in 2000. Otitis media was a major cost driver for physician visits. RSV infection-related hospitalisations increased from 1993 to 2000, but average costs per hospitalisation were relatively stable. Treatment of RSV infection-related illness represents a significant healthcare burden in the US. The economic impact of ambulatory care for RSV infection-related illness could be as important as that for RSV infection-related hospitalisation.