Emergence of parapneumonic empyema in the USA

Abstract

Background Although recent reports suggest that the incidence of parapneumonic empyema has increased in several regions of the USA, national trends in disease burden are unknown. National trends in the incidence of parapneumonic empyema hospitalisations and changes in empyema by associated pathogens were examined. Methods National hospitalisation data (1996e2008) were analysed and rates estimated using census estimates as denominators. Incidence rate ratios (IRR) compared 2008 with 1996 rates. Discharge diagnosis codes were used to characterise pathogens associated with empyema hospitalisations. Results Overall, national parapneumonic empyemarelated hospitalisation rates increased from 3.04 per 100 000 in 1996 to 5.98 per 100 000 in 2008, a 2.0-fold increase (95% CI 1.8 to 2.1). The increases were observed among children (IRR 1.9 (95% CI 1.4 to 2.7)) and adults aged 18e39, 40e64 and $65 years (IRR 1.8 (95% CI 1.5 to 2.1), 2.0 (95% CI 1.6 to 3.1) and 1.7 (95% CI 1.5 to 2.0), respectively). Overall, pneumococcal empyema rates remained relatively stable in all age groups whereas streptococcal-(non-pneumococcal) and staphylococcal-related empyema rates increased 1.9-fold and 3.3-fold, respectively, with consistent increases across age groups. The overall in-hospital case fatality ratio for parapneumonic empyema-related hospitalisations was 8.0% (95% CI 6.4% to 9.5%) in 1996 and 7.2% (95% CI 6.3% to 8.1%) in 2008 (p¼0.395). Of the empyemas where study pathogens were listed (37.6%), staphylococcal-related empyema had the largest absolute increases across age groups and was associated with longer hospital stay and higher in-hospital mortality than other empyemas. Conclusions Although parapneumonic empyemarelated hospitalisations remained relatively rare, they increased substantially during the study period. A number of pathogens, especially staphylococcus, contributed to this increase.

Sinusitis and Pneumonia Hospitalization After Introduction of Pneumococcal Conjugate Vaccine

“…Grijalva et al 34,35 showed a twofold increase in hospitalizations for parapneumonic empyema after vaccine introduction in children in the United States. Serotypes 1 and 3 have been associated with empyema, and because they are not included in PCV7, serotype replacement may cause increased rates of empyema after vaccine introduction.…”

Infectious pleural effusion status and treatment progress

“…For example, from 1996 to 2008, admission rate has been increased two times for the patients suffering from empyema in America (3.04-5.98/100,000) (1). These changes are possibly related to the enhancement of clinical diagnosis awareness and the increasing number of available examination methods, allowing physicians to better identify pleural cavity infection.…”

“…Infectious pleural effusion status and treatment progress Epidemiology Globally (13)(14)(15), pleural cavity infection occurrence rate has been constantly increasing for each age group with an unknown cause (1,16). For example, from 1996 to 2008, admission rate has been increased two times for the patients suffering from empyema in America (3.04-5.98/100,000) (1).…”

“…Approximately 80,000 British and American adults have suffered from thoracic cavity infection each year, with medical expenses of approximately USD 500 million (1,2). Even though the prognosis of most patients has been relatively good, serious complications could occur for some patients.…”

Pleural infection

“…2,3,19 Following the introduction of the 7-valent pneumococcal conjugate vaccine, there is evidence that the non-vaccine serotype 1 is causing increasing cases of pleural infection and other invasive pneumococcal disease. Diabetes, the immunosuppressed state, alcohol misuse and intravenous (iv) drug abuse have been shown to be risk factors for pleural infection in adults.…”