BACKGROUND AND OBJECTIVE The impact of inhaled corticosteroid (ICS) use on the development of pneumonia has been heavily debated. The aim of this study was to elucidate the association between the use of inhalers, including ICS, and a hospital admission or an emergency room (ER) visit for pneumonia.

METHODS A case-crossover study was conducted based on the Korean national claims database. We identified users of respiratory inhalers admitted to the hospital or having visited the ER for pneumonia between 1 January 2008 and 31 December 2010. The case period was defined as 0-30 days before the event. Control periods of 30-60, 90-120, 180-210 and 360-390 days before the event were used.

RESULTS A total of 186 018 inhaler users were admitted to the hospital or visited the ER for pneumonia during the study period. With the period 30-60 days before the event as a control, the use of an ICS without a long-acting β2 agonist (LABA) was associated with an increased risk of hospital admission or ER visit for pneumonia (adjusted odds ratio (aOR), 1.73; 95% confidence interval (CI): 1.64-1.83). In contrast, the use of an ICS and a LABA was associated with a decreased risk for pneumonia-related hospital admission or ER visit (aOR, 0.63; 95% CI: 0.61-0.66).

CONCLUSIONS We suggest that the use of ICS with LABA decreases the risk of hospital admission or ER visit for pneumonia, whereas the use of ICS alone may increase that risk.