Table of Contents Author Guidelines Submit a Manuscript
International Journal of Rheumatology
Volume 2017 (2017), Article ID 6730812, 8 pages
Research Article

Incidence and Risk Factors for Infections Requiring Hospitalization, Including Pneumocystis Pneumonia, in Japanese Patients with Rheumatoid Arthritis

1Department of Rheumatology, National Hospital Organization Sagamihara National Hospital, Sagamihara, Japan
2Department of Rheumatology, Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital, Sagamihara, Japan
3Department of Clinical Laboratory, National Hospital Organization Sagamihara National Hospital, Sagamihara, Japan
4Molecular and Genetic Epidemiology Laboratory, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan

Correspondence should be addressed to Atsushi Hashimoto

Received 11 June 2017; Revised 23 August 2017; Accepted 17 September 2017; Published 18 October 2017

Academic Editor: Bruce M. Rothschild

Copyright © 2017 Atsushi Hashimoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. Rheumatoid arthritis (RA) may be complicated by different infections, but risk factors for these are not fully elucidated. Here, we assessed the incidence of and risk factors for infections requiring hospitalization (IRH) including pneumocystis pneumonia (PCP) in patients with RA. Methods. We retrospectively surveyed all RA patients treated at our hospital from 2009 to 2013, for whom data were available on demographic features, medications, comorbidities, and severity of RA. Multivariate logistic regression analysis was applied to calculate adjusted odds ratios (ORs) for factors associated with the occurrence of IRH. Results. In a total of 9210 patient-years (2688 patients), there were 373 IRH (3.7/100 patient-years). Respiratory tract infections were most frequent (, and additionally 16 PCP), followed by urinary tract infections (). Significant factors for PCP included higher age (≥70 years; OR 3.5), male sex (6.6), underlying lung disease (3.0), use of corticosteroids (4.8), and use of biologics (5.4). Use of methotrexate (5.7) was positively associated with PCP but negatively with total infections (0.7). Additionally, functional disorders and higher RA disease activity were also related to total infections. Conclusions. Risk factors for infection should be taken into account when deciding treatment for the individual RA patient.