Recent epidemiology of Pneumocystis pneumonia in Japan

Abstract

Objectives: The objective of this study was to describe the recent epidemiology of Pneumocystis pneumonia (PCP) in Japan using a nationwide database.

Methods: We extracted data of inpatients with PCP from the Diagnostic Procedure Combination database, a national inpatient database in Japan, from January 2010 to December 2016.

Results: During the study period, 4293 PCP patients were identified, including 4073 adults and 220 children. In adults, the most common comorbidity was hematologic malignancy (31%), followed by diabetes mellitus (30%), rheumatic/collagen diseases (26%), and solid organ tumors (18%). In children, there were few patients with rheumatic diseases (5%) or diabetes mellitus (2%), but immunodeficiency (without human immunodeficiency virus) was more common (28%). Few biological products were used for adult and pediatric patients; CD20 inhibitors, TNF-α inhibitors, interleukin receptor inhibitors, and CTLA-4 inhibitor were used for 8.6% and 2.4%, 1.3% and 0%, 1.2% and 4.7%, and 0.2% and 0% of adult and pediatric patients, respectively. Based on data stratified by bed count, the annual numbers of PCP patients in Japan were estimated as 2221 adults and 123 pediatric patients. The mortality was higher in adults (27%) than in pediatric patients (21%) (P = 0.041).

Conclusions: The underlying disease and mortality were apparently different between adult and pediatric PCP patients.

Keywords: Database; Pediatrics; Pneumocystis pneumonia.