Trends in Legionnaires’ Disease-Associated Hospitalizations, United States, 2006–2010

Abstract

Background Legionella pneumophila is a waterborne cause of both healthcare-associated and community-acquired pneumonia. Legionella pneumophila serogroup 1 is responsible for 80% of infections. There is currently limited published disease burden data on Legionnaires’ disease-associated hospitalization in the United States. Methods In this study, we estimated the annual incidence of Legionnaires’ disease-associated hospitalizations in United States and identified demographic, temporal, and regional characteristics of individuals hospitalized for Legionnaires’ disease. A retrospective study was conducted using the National Hospital Discharge Survey (NHDS) data from 2006 to 2010. The NHDS is a nationally representative US survey, which includes estimates of inpatient stays in short-stay hospitals in the United States, excluding federal, military, and Veterans Administration hospitals. All discharges assigned with the Legionnaires’ disease International Classification of Diseases 9th Clinical Modification discharge diagnostic code (482.84) were included in this study. Results We observed the annual incidence and number of Legionnaires’ disease-associated hospitalizations (per 100 000 population) in the United States by year, age, sex, race, and region. Over a 5-year period, 14 574 individuals experienced Legionnaires’ disease-associated hospitalizations in the United States The annual population-adjusted incidence (per 100 000 population) of Legionnaires’ disease-associated hospitalizations was 5.37 (95% confidence interval [CI], 5.12–5.64) in 2006, 7.06 (95% CI, 6.80–7.40) in 2007, 8.77 (95% CI, 8.44–9.11) in 2008, 17.07 (95% CI, 16.62–17.54) in 2009, and 9.66 (95% CI, 9.32–10.01) in 2010. A summer peak of Legionnaires’ disease-associated hospitalizations occurred from June through September in 2006, 2007, 2008, and 2010. Conclusions Legionnaires’ disease-associated hospitalizations significantly increased over the 5-year study period. The increasing disease burden of Legionnaires’ disease suggests that large segments of the US population are at risk for exposure to this waterborne pathogen.

Legionnaires’ Disease: Update on Diagnosis and Treatment

“…Although information on legionellosis has improved in recent decades, its incidence remains unknown, mainly because it is underdiagnosed and underreported. Countries differ in terms of their level of surveillance, diagnostic methods, and investigation efforts [ 1 , 2 , 22 , 23 ]. An increase in the incidence of the condition has been documented, although the causes are not entirely clear.…”

“…More recently, 6141 cases were reported in 2016 and 7458 in 2017 [ 26 ]. Another retrospective study evaluated Legionnaires’ disease-associated hospitalizations using the US National Hospital Discharge Survey (NHDS) data from 2006 to 2010, and found significant increases in Legionnaires’ over the 5-year study period (from 5.37 per 100,000 population in 2006 to 9.66 in 2010, with a peak in 2009 of 17.07) [ 22 ]. Likewise, the European Legionnaires’ disease Surveillance Network (ELDSNet) reported that the notification rates for Legionnaires’ disease have nearly doubled in the past few years, from 1.4 in 2015 to 2.2 per 100,000 population in 2019, and mostly involved men aged 65 years and above.…”

An Epidemiological Study on Legionnaires’ Disease in Gyeonggi Province, Korea: Occurrence, Infection Routes, and Risk Factors for Mortality (2016–2022)

“…Previous studies have commonly identified Legionella bacteria in patients hospitalized with pneumonia in community settings [7][8][9]. Considering the essential role of water in residential settings for activities like showering and bathing, the potential for communityacquired Legionella infections is always present.…”

Healthcare-Associated Legionella Disease: A Multi-Year Assessment of Exposure Settings in a National Healthcare System in the United States

“…Disease caused by Legionella is acute and typically occurs 2 to 14 days after exposure. Cases of LD, while likely underdiagnosed [ 11 ], have been increasing over time [ 3 , 10 , 12 ] as have LD-associated hospitalizations [ 13 ].…”