# Estimation of Respiratory Syncytial Virus-attributable hospitalizations among older adults in Japan between 2015 and 2018: An administrative health claims database analysis

## TL;DR

This study estimates the number of hospitalizations in older adults in Japan caused by respiratory syncytial virus from 2015 to 2018, showing a significant disease burden.

## Contribution

The study provides new estimates of RSV-attributable hospitalization rates in older Japanese adults using a time-series model and administrative health claims data.

## Key findings

- Annual RSV-attributable cardiorespiratory hospitalization rates ranged from 100 to 124 per 100,000 person-years in DPC hospitals.
- Hospitalization rates were higher in adults aged ≥80 years compared to those aged 60–79 years.
- The study highlights the need for effective RSV prevention strategies in older adults.

## Abstract

We estimated the incidence rates (IRs) of respiratory syncytial virus (RSV)-related hospitalizations among adults aged ≥60 years in Japan from 2015 to 2018, using a time-series model-based approach to better understand the disease burden. We obtained hospitalization data from the Medical Data Vision (MDV) database, restricted to Diagnosis Procedure Combination (DPC) hospitals. We estimated the annual age-specific RSV-attributable IR of hospitalizations for five cardiorespiratory outcomes based on selected ICD-10 codes employing a quasi-Poisson regression model. We projected our results to all DPC hospitals in Japan and also to all Japanese hospitals. In adults aged ≥60 years, the annual IR of RSV-attributable cardiorespiratory hospitalizations at DPC hospitals was estimated at between 100 and 124 per 100,000 person-years, projecting to 134–229 cardiorespiratory hospitalizations per 100,000 person-years at all hospitals. For respiratory hospitalizations at DPC hospitals, the annual IR was from 69 to 85 per 100,000 person-years (projecting to 96–157 hospitalizations per 100,000 person-years at all hospitals). IRs for all outcomes were consistently higher among adults aged ≥80 years than those 60–79 years. Our results indicate a high burden of RSV-attributable hospitalizations in older adults in Japan, highlighting the need to implement effective RSV prevention strategies.