The Burden and Etiology of Community-Onset Pneumonia in the Aging Japanese Population: A Multicenter Prospective Study

Abstract

BackgroundThe increasing burden of pneumonia in adults is an emerging health issue in the era of global population aging. This study was conducted to elucidate the burden of community-onset pneumonia (COP) and its etiologic fractions in Japan, the world’s most aged society.MethodsA multicenter prospective surveillance for COP was conducted from September 2011 to January 2013 in Japan. All pneumonia patients aged ≥15 years, including those with community-acquired pneumonia (CAP) and health care-associated pneumonia (HCAP), were enrolled at four community hospitals on four major islands. The COP burden was estimated based on the surveillance data and national statistics.ResultsA total of 1,772 COP episodes out of 932,080 hospital visits were enrolled during the surveillance. The estimated overall incidence rates of adult COP, hospitalization, and in-hospital death were 16.9 (95% confidence interval, 13.6 to 20.9), 5.3 (4.5 to 6.2), and 0.7 (0.6 to 0.8) per 1,000 person-years (PY), respectively. The incidence rates sharply increased with age; the incidence in people aged ≥85 years was 10-fold higher than that in people aged 15-64 years. The estimated annual number of adult COP cases in the entire Japanese population was 1,880,000, and 69.4% were aged ≥65 years. Aspiration-associated pneumonia (630,000) was the leading etiologic category, followed by Streptococcus pneumoniae-associated pneumonia (530,000), Haemophilus influenzae-associated pneumonia (420,000), and respiratory virus-associated pneumonia (420,000), including influenza-associated pneumonia (30,000).ConclusionsA substantial portion of the COP burden occurs among elderly members of the Japanese adult population. In addition to the introduction of effective vaccines for S. pneumoniae and influenza, multidimensional approaches are needed to reduce the pneumonia burden in an aging society.

Serotype Replacement in Adult Pneumococcal Pneumonia after the Introduction of Seven-Valent Pneumococcal Conjugate Vaccines for Children in Japan: a Systematic Literature Review and Pooled Data Analysis

“…All of the studies were performed in the pre-PCV13 period. The study designs could be categorized into case series of pneumococcal LRTI (15,16), prospective surveillance of pneumococcal LRTI or IPD cases (1,(17)(18)(19)(20), and laboratory-based pneumococcal strain surveillance (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). One of the prospective surveillance studies of the LRTI referred to the Japanese Respiratory Society (JRS) guidelines for the management of community-acquired pneumonia in adults (36) as diagnostic criteria for LRTI (17).…”

“…One of the prospective surveillance studies of the LRTI referred to the Japanese Respiratory Society (JRS) guidelines for the management of community-acquired pneumonia in adults (36) as diagnostic criteria for LRTI (17). Another 3 prospective surveillance studies of pneumonia also used similar case definitions to the JRS guidelines (1,18,19). All the laboratory-based pneumococcal strain surveillance studies were designed to test the collected pneumococcal strains from various specimens such as sputum, respiratory tract aspirates, nasopharyngeal swabs, eye or ear discharge, blood, cerebrospinal fluid, and pleural fluid.…”

“…The other "largely relevant" study included 1,200 CAP cases and 572 healthcare-associated pneumonia cases. This study reported the pneumococcal serotype of 100 strains out of a total of 142 isolates of pneumococcus (1).…”

“…Streptococcus pneumoniae (pneumococcus) is one of the most common causative agents for adult pneumonia (1)(2)(3)(4). Recent studies from Europe reported that approximately 30 of pneumonia cases resulted from a pneumococcal infection (2,4).…”

“…Our previously published multicenter prospective study showed that pneumococcus was detected in 26.2 of all community-onset pneumonia cases, and the estimated incidence of adult pneumococcal pneumonia in Japan was 473 cases per 100,000 person-years (PYs) (1). However, in our study population, the proportion of cases of bacteremic pneumococcal pneumonia was less than 5 of the pneumococcal pneumonia cases, which was much lower than the 24.8 estimated by a meta-analysis based on multi-country studies (3), and the estimated incidence was only 12 cases per 100,000 PYs (1).…”