Legionellosis-Associated Hospitalization in Spain from 2002 to 2021

Legionellosis is a respiratory disease of bacterial and environmental origin that usually presents two distinct clinical entities, "Legionnaires' disease" (LD) and "Pontiac fever". LD is an important cause of hospital-acquired pneumonia (HAP). The objective of this study is to describe the epidemiology of legionellosis-associated hospitalization (L-AH) in Spain from 2002 to 2021 and the burden of hospitalization due to legionellosis. Discharge reports from the Minimum Basic Data Set (MBDS) were used to retrospectively analyze hospital discharge data with a diagnosis of legionellosis, based on the ICD-9-CM and ICD-10-CM diagnosis codes, from 2002 to 2021. 21,300 L-AH occurred throughout the year during 2002-2021. The incidence of hospitalization associated per 100,000 inhabitants by month showed a similar trend for the 2002-2011, 2012-2021, and 2002-2021 periods. In Spain, during 2002-2021, the hospitalization rate (HR) in the autonomous communities ranged from 4.57 (2002-2011) to 0.24 (2012-2021) cases per 100,000 inhabitants. The HR of legionellosis in Spain has substantially increased across the 2002-2021 period, and the estimate is consistent with available European data. It is considered that in-depth epidemiological surveillance studies of legionellosis and improvements in the prevention and control of the disease are required in Spain.