High Incidence of Community-Acquired Pneumonia among Rapidly Aging Population in Japan: A Prospective Hospital-Based Surveillance

Masahiro Takaki; Takahiro Nakama; Masayuki Ishida; Hitomi Morimoto; Yuka Nagasaki; Rina Shiramizu; Naohisa Hamashige; Masayuki Chikamori; Laymyint Yoshida; Koya Ariyoshi; Motoi Suzuki; Konosuke Morimoto

doi:10.7883/yoken.67.269

Original Article

High Incidence of Community-Acquired Pneumonia among Rapidly Aging Population in Japan: A Prospective Hospital-Based Surveillance

Masahiro Takaki, Takahiro Nakama, Masayuki Ishida, Hitomi Morimoto, Yuka Nagasaki, Rina Shiramizu, Naohisa Hamashige, Masayuki Chikamori, Laymyint Yoshida, Koya Ariyoshi, Motoi Suzuki, Konosuke Morimoto

Author information

Masahiro Takaki
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Takahiro Nakama
Department of Respiratory Medicine, Chikamori Hospital
Masayuki Ishida
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Hitomi Morimoto
Department of Laboratory, Chikamori Hospital
Yuka Nagasaki
Department of Laboratory, Chikamori Hospital
Rina Shiramizu
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Naohisa Hamashige
Department of Internal Medicine, Chikamori Hospital
Masayuki Chikamori
Department of Dialysis, Chikamori Hospital
Laymyint Yoshida
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Koya Ariyoshi
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Motoi Suzuki
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University
Konosuke Morimoto
Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University

Keywords: community-acquired pneumonia, ageing, age-group-specific incidence, respiratory virus, Streptococcus pneumoniae

JOURNAL FREE ACCESS

2014 Volume 67 Issue 4 Pages 269-275

DOI https://doi.org/10.7883/yoken.67.269

Details

Abstract

The age-group-specific incidence and etiological patterns of community-acquired pneumonia (CAP) have not been fully established in Japan. A 2-year prospective surveillance was conducted in Kochi city, Western Japan. All CAP patients aged ≥15 years who visited a community-based hospital were enrolled in the study. Clinical samples were examined by conventional bacterial culture and urinary antigen tests, and 6 bacterial pathogens and 16 respiratory viruses were identified from sputum samples by multiplex polymerase chain reaction assays. The age-group-specific incidence of CAP was estimated using a population-based data set of the total number of outpatients in the whole city. Ninety of the 131 enrolled patients, 68.7% were positive for respiratory pathogens. Streptococcus pneumoniae was the leading bacterial pathogen identified (28.2%). Respiratory viruses were identified in 36 patients (27.5%), and human entero–rhinovirus was the most common (13.3%) among them. The estimated overall incidence of adult CAP in Kochi was 9.6 per 1,000 person-years (PY); the estimated age group-specific incidence was 3.4, 10.7, and 42.9 per 1,000 PY for those aged 15–64, 65–74, and ≥75 years, respectively. The high incidence of CAP in these rural city of Japan, probably reflects the substantial aged population. S. pneumoniae and respiratory viruses play important roles in CAP in all age groups.

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