Association between bed supply and pneumonia hospitalization according to hospital types in Korea

BACKGROUND: An ecological study was conducted to determine the causes of regional differences in hospitalized pneumonia incidence in Korea. We evaluated the association between regional bed capacity and pneumonia hospitalization rates, and the interaction of hospital type. METHODS: Variables of hospitalized pneumonia patients (n = 2,226,243) aged 19 years from 2015 to 2020, prior to the COVID-19 pandemic, were extracted from the Korean National Insurance database. Age-standardized pneumonia hospitalization rates per 10,000 population by region and year were calculated. Multilevel linear regression was conducted to assess the association between the regional number of beds by hospital type and pneumonia hospitalization rates. The multilevel analysis was stratified by length of stay (LOS) and whether recommended clinical practices for pneumonia treatment were performed during hospitalization. RESULTS: Pneumonia hospitalization rates were highest in the Gwangju metropolitan city. The excessive pneumonia hospitalization rate in Gwangju occurred mainly in primary care (PC) and nursing care (NC) hospitals. A significant positive association between regional number of bed supply and pneumonia hospitalization rates (p-value=0.0157) was found. Interaction effect of hospital type and regional bed number supply was statistically significant (p-value<0.001). Positive association between regional bed supply and hospitalization rates was prominent in low grade hospitals, such as PC or NC hospital, and with the poor adequacy of pneumonia care, including long LOS and without recommended clinical practices. CONCLUSIONS: The results suggest that while public health benefits can be expected from increased regional bed availability, there may be unexpected harms associated with supplier-induced demand for hospitalization, mostly in inferior hospitals. Therefore, hospital type and quality of medical care also should be considered in the process of expanding bed capacity in a region. KEY MESSAGES: • Regional difference of pneumonia hospitalization rates was associated with hospital bed capacity. • Supplier induced hospitalization of pneumonia occurred mainly in inferior type of hospital.