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Background: POCUS training courses are effective at improving knowledge and skills, but few studies have followed learners longitudinally post-course to understand facilitators, barriers, and changes in POCUS use in clinical practice. We conducted a prospective observational study of physicians who attended 11 standardized POCUS training courses between 2017 and 2019 in Japan. Physicians who attended a standardized POCUS course were surveyed about their current frequency of POCUS use of the heart, lung, abdomen, and lower extremity veins, and perceived barriers and facilitators to POCUS use in clinical practice. Results: Data were analyzed from 112 completed surveys (response rate = 20%). A majority of responding physicians were faculty (77%) in internal medicine (69%) affiliated with community hospitals (55%). The mean delay between course attendance and survey response was 50.3 months. A significant increase in POCUS use from < 1 to ≥ 1 time per week was seen for all organ systems after 50 months post-course (p < 0.01). Approximately half of course participants reported an increase in the frequency of cardiac (61%), lung (53%), vascular (44%), and abdominal (50%) ultrasound use. General facilitators of POCUS use were easy access to ultrasound machines (63%), having a colleague with whom to learn POCUS (47%), and adequate departmental support (46%). General barriers included lack of opportunities for POCUS training (47%), poor access to ultrasound machines (38%), and limited time for POCUS training (33%). In the group with increased POCUS usage, specific facilitators reported were enhanced POCUS knowledge, improved image acquisition skills, and greater self-confidence in performing POCUS. Conversely, the group without increased POCUS usage reported lack of supervising physicians, low confidence, and insufficient training opportunities as specific barriers. Conclusions: Approximately half of physicians reported an increase in cardiac, lung, vascular, and abdominal POCUS use > 4 years after attending a POCUS training course. In addition to improving access to ultrasound machines and training opportunities, a supportive local clinical environment, including colleagues to share experiences in learning POCUS and local experts to supervise scanning, is important to foster ongoing POCUS practice and implementation into clinical practice. [ABSTRACT FROM AUTHOR]

Background: An increased focus on quality and patient safety has led to the evolution of hospitalists. The number of hospitalists covering ward and outpatient care is on the rise in Japan. However, it is unclear what roles hospital workers themselves consider important in their practice. Therefore, this study investigated what hospitalists and non-hospitalist generalists in Japan consider important for the practice of their specialty. Methods: This was an observational study that included Japanese hospitalists (1) currently working in a general medicine (GM) or general internal medicine department and (2) working at a hospital. Using originally developed questionnaire items, we surveyed the items important to hospitalists and non-hospitalist generalists. Results: There were 971 participants (733 hospitalists, 238 non-hospitalist) in the study. The response rate was 26.1%. Both hospitalists and non-hospitalists ranked evidence-based medicine as the most important for their practice. In addition, hospitalists ranked diagnostic reasoning and inpatient medical management as the second and third most important roles for their practice, while non-hospitalists ranked inpatient medical management and elderly care as second and third. Conclusions: This is the first study investigating the roles Japanese hospitalists consider important and comparing those to that of non-hospitalist generalists. Many of the items that hospitalists considered important were those that hospitalists in Japan are working on within and outside academic societies. We found that diagnostic medicine and quality and safety are areas that are likely to see further evolution as hospitalists specifically emphasized on them. In the future, we expect to see suggestions and research for further enhancing the items that hospital workers value and emphasise upon. [ABSTRACT FROM AUTHOR]

Simple Summary: Extrahepatic cholangiocarcinoma (EHCC) is an aggressive tumor. The five-year survival rate for patients who undergo surgical resection is only 20–40% due to recurrences. Therefore, elucidating the molecular mechanisms underlying invasion and metastasis in EHCC is crucial for developing adjuvant therapy. The epithelial–mesenchymal transition (EMT) contributes to the metastatic cascade in various tumors. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine (C-C motif) ligand 19 (CCL19), to promote EMT. The association between CCR7 expression and clinicopathological features and EMT status was examined via the immunohistochemical staining of tumor sections from 181 patients with perihilar cholangiocarcinoma. This association was then investigated in two EHCC cell lines. CCR7 mediates cell invasion and migration in EHCC by inducing EMT, which was abrogated by a CCR7 antagonist. CCR7 may be a potential target for adjuvant therapy in EHCC. The epithelial–mesenchymal transition (EMT) contributes to the metastatic cascade in various tumors. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine (C-C motif) ligand 19 (CCL19), to promote EMT. However, the association between EMT and CCR7 in extrahepatic cholangiocarcinoma (EHCC) remains unknown. This study aimed to elucidate the prognostic impact of CCR7 expression and its association with clinicopathological features and EMT in EHCC. The association between CCR7 expression and clinicopathological features and EMT status was examined via the immunohistochemical staining of tumor sections from 181 patients with perihilar cholangiocarcinoma. This association was then investigated in TFK-1 and EGI-1 EHCC cell lines. High-grade CCR7 expression was significantly associated with a large number of tumor buds, low E-cadherin expression, and poor overall survival. TFK-1 showed CCR7 expression, and Western blotting revealed E-cadherin downregulation and vimentin upregulation in response to CCL19 treatment. The wound healing and Transwell invasion assays revealed that the activation of CCR7 by CCL19 enhanced the migration and invasion of TFK-1 cells, which were abrogated by a CCR7 antagonist. These results suggest that a high CCR7 expression is associated with an adverse postoperative prognosis via EMT induction and that CCR7 may be a potential target for adjuvant therapy in EHCC. [ABSTRACT FROM AUTHOR]

Background: In Japan, the nurse practitioner (NP) system has only been in place for a short time, and there is no ultrasound (US) simulation course for NPs. Therefore, NPs may have to attend US simulation courses for physicians. We evaluated whether US simulation course for physicians lead to improved image acquisition and interpretation amongst NPs and, if so, if these changes would be maintained over time. Methods: A 2-day point-of-care ultrasound (POCUS) course designed for physicians in cardiac US, lung US, lower extremity deep vein thrombosis (DVT) US, and abdominal US was held for Japanese nurse practitioners (JNP) and JNP trainees in 2018 and 2019. Participants kept a record of the number of US examinations they performed for 3 months before and 3 months after the course. The number of US exams performed was grouped into six categories. All participants underwent pre-course, immediate post-course, and 4-month post-course testing to assess image interpretation skills, image acquisition skills, and confidence. Results: Thirty-three participants from 21 facilities completed the program. Before and immediately after the course, test scores of the image interpretation test, image acquisition test, and confidence increased significantly (37.1, 72.6: P < 0.001), (13.7, 53.6: P < 0.001), and (15.8, 35.7: P < 0.001), respectively. Comparing the follow-up tests immediately after the course and 4 months later, there was no decrease in scores on the image interpretation test, the image acquisition test, or confidence (72.6, 71.8: P = 1.00) (53.6, 52.9: p = 1.00) (35.7, 33.0: P = 0.34). There was a statistically significant increase (P < 0.001) in both the total number of ultrasound examinations and in the number of ultrasound examinations by category (cardiac, lung, lower extremity DVT, and abdominal) in the 3 months before and 3 months after the course. Conclusions: The POCUS simulation course for physicians is useful for JNPs to acquire US examination skills even if it is not arranged for JNPs. Image interpretation skill, image acquisition skill, and confidence improved significantly and were maintained even after 4 months of the course. It leads to behavioral changes such as increasing the number of US examinations in daily practice after the course. [ABSTRACT FROM AUTHOR]

Purpose: To identify the current ambiguous status of general medicine (GM) and assess current problems and weaknesses for further development of GM. Patients and Methods: This study adopted an observational design. GM practitioners were selected from the mailing lists of two primary professional associations for Japanese GM doctors. We included physicians currently working in a GM department, those self-described as GM doctors, and those board-certified in family medicine or general internal medicine. Respondents replied to survey questions about their sociodemographic data, job descriptions, and the requisite skills for practice. GM doctors' job description and required skills were categorized into "clinical," "management," "education," and "research." Participants (n = 971) were compared based on job descriptions and important skills in each category by facility type, size, and position. Results: "Clinical" was indicated as the most important category for both job description and important skills, followed by "management," "education," and "research." For job description details, "follow-up outpatient" (35.6%) ranked first for "clinical," and "resident education" (57.3%) ranked first for "education." By facility type and size, job description and important skills decreased for clinical and management categories as facility sizes increased; the opposite was true for "education." "Research" was generally rated low. By position, no significant difference was found in effort or importance given to research. Conclusion: This study is the first survey on GM physicians across Japan. The results show that while Japanese GM physicians focus on and place importance on clinical practice, they are less involved in research and do not consider research skills to be important. The challenge for the future development of GM lies in research. [ABSTRACT FROM AUTHOR]

Lessons Learned: Low‐dose afatinib maintenance treatment among patients with EGFR‐mutated NSCLC achieved long‐time to treatment failure with fewer treatment‐related AEs without detracting from the therapeutic efficacy.This modified regimen represents a practical usage that balances effectiveness and safety. Background: Although afatinib is an effective therapy for patients with EGFR‐mutated non‐small cell lung cancer (NSCLC), drug‐related adverse events (AEs) have often necessitated dose reductions. In a post hoc analysis of the LUX‐Lung 3 and 6 trials, there was no difference in median progression‐free survival (PFS) between patients who had the dose of afatinib reduced and those who did not. We thus evaluated the efficacy and tolerability of low‐dose afatinib maintenance treatment among patients with NSCLC harboring EGFR mutations who had not been previously treated. Methods: Eligible patients received afatinib 40 mg orally once daily. When prescribed grade ≥ 2 AEs, rash of grade ≥ 3, or unacceptable toxicity occurred, the afatinib dose was reduced from 40 to 30 mg and if needed from 30 to 20 mg. The primary endpoint was the 1‐year PFS rate. Secondary endpoints were PFS, overall response rate (ORR), and toxicity. Results: Among 30 patients, 93% had adenocarcinoma, 53% had exon 19 deletion, 37% had L858R, and 10% had minor mutations. The 1‐year PFS rate was 50% (95% confidence interval [CI], 31.3–66.1) and the median PFS was 11.8 months (95% CI, 7.1–21.4). The incidence rate of grade ≥ 3 toxicities was 57%, including elevated aspartate aminotransferase/alanine aminotransferase level (13%), diarrhea (10%), and paronychia (10%). Conclusion: Low‐dose afatinib maintenance treatment reduced treatment‐related AEs without detracting from the therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Based on my ethnographic observation of the risk discussion of the possible spread of foot-and-mouth disease in Nagasaki's Fukue Island in the summer of 2010, I examine how members of a local community in Japan attempted to discursively link their local-level political-economic decision with what they believed to be a global discourse. By comparing it with the counter discourse from those in Japan's tourism industry and an athletic community, I argue that two different risk discourses at the local level are influenced by the complex processes of globalization. [ABSTRACT FROM PUBLISHER]

To determine the incidence of malignancy and site-specific malignancies in Japanese patients with rheumatoid arthritis (RA). In a prospective large observational cohort study named IORRA, 7,566 patients with RA were enrolled from April 2001 to April 2005 and were followed up to October 2005. Occurrence of malignancy was originally collected by patient reports of IORRA survey biannually from April 2001 to October 2005, and was confirmed by medical records. Standardized incidence rate (SIR) of the observed-to-expected cancer incidence and 95% confidence intervals (95% CI) were then calculated. Factors obtained at first enrollment in IORRA were assessed for association with risk of malignancy using the Cox proportional hazards model. A total of 177 malignancies in 173 patients (58 in men, 115 in women) were identified during the observation period of 25,567 person-years. The age- and sex-standardized incidence rate of malignancy was 437.1 (men, 706.8; women, 366.1) per 100,000 person-years. The SIR of malignancy was slightly excess (SIR 1.18, [95% CI 1.02-1.37]) in all patients, but 1.29 (95% CI 0.99-1.67) in men, and 1.13 (95% CI 0.94-1.36) in women. A significant excess of lymphoma (SIR 6.07, [95% CI 3.71-9.37]) and lung cancer (SIR 2.29, [95% CI 1.57-3.21]), whereas decreased incidence of colorectal cancer (SIR 0.49, [95% CI 0.26-0.83]), were found. Male gender and older age were identified as risk factors for malignancy. A slight excess in the incidence of overall malignancy and highly excess of lymphoma in Japanese RA patients was demonstrated. [ABSTRACT FROM AUTHOR]

Our aim was to provide nomograms that allow urologists to easily calculate a nonmuscle invasive bladder cancer patient’s risk of recurrence and progression. We retrospectively analyzed 800 nonmuscle invasive bladder cancer patients newly diagnosed between 1991 and 2001 from the Gifu urothelial cancer registry program. We developed the nomogram using the original 500 patients and validated it using the remaining 300 patients. The prognostic factors of recurrence and progression were identified by multivariate analysis in 500 patients. In the multivariate analysis, tumor number, shape, grade, and intravesical instillation were associated with recurrence-free survival. Tumor shape and grade were associated with progression-free survival. Six factors for recurrence and three factors for progression were used to make the nomogram. Using the original 500 patients who were modeled for the nomogram, the areas under the receiver operating characteristic curves (AUCs) were calculated to be 0.61 for recurrence and 0.71 for progression. To validate nomogram performance, we applied an additional 300 patients to the nomograms. The AUCs were 0.57 for recurrence and 0.67 for progression. The nomograms that have been developed can be used to predict the probability of recurrence and progression of nonmuscle invasive bladder cancer. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to translate the TeamSTEPPS® Teamwork Perceptions Questionnaire (T-TPQ) into Japanese and assess its validity and reliability., Design: Translation of the T-TPQ and a cross-sectional survey., Methods: Following a forward and back translation of the questionnaire, content validity was assessed by an expert panel using item-level content validity index. Construct validity was assessed by a confirmatory factor analysis. Further, intraclass correlation coefficient was estimated by test-retest methods., Results: A total of 587 healthcare professionals responded to the translated T-TPQ. The item-level content validity index ranged between 0.8 and 1.0, indicating an acceptable content validity. The multiple fit indices showed an acceptable fitting model. Fifty-one healthcare professionals participated in the test-retest method. Intraclass correlation coefficients for all dimensions ranged from 0.838 to 0.957, indicating acceptable test-retest reliability. Our findings suggest that the Japanese version of the T-TPQ has acceptable validity and reliability., Competing Interests: No conflict of interest has been declared by the authors., (© 2020 The Authors. Nursing Open published by John Wiley & Sons Ltd.)

Background: Few studies have compared the effectiveness of brief training courses on point-of-care ultrasound (POCUS) skill acquisition of novice attending physicians vs. trainees. The purpose of this study was to evaluate the change in POCUS image interpretation skills and confidence of novice attending physicians vs. trainees after a 1-day POCUS training course., Methods: A 1-day POCUS training course was held in March 2017 in Japan. A standardized training curriculum was developed that included online education, live lectures, and hands-on training. The pre-course assessment tools included a written examination to evaluate baseline knowledge and image interpretation skills, and a physician survey to assess confidence in performing specific ultrasound applications. The same assessment tools were administered post-course, along with a course evaluation. All learners were novices and were categorized as trainees or attending physicians. Data were analyzed using two-way analysis of variance., Results: In total, 60 learners attended the course, and 51 learners (85%) completed all tests and surveys. The 51 novice learners included 29 trainees (4 medical students, 9 PGY 1-2 residents, 16 PGY 3-5 residents) and 22 attending physicians (6 PGY 6-10 physicians, and 16 physicians PGY 11 and higher). The mean pre- and post-course test scores of novice trainees improved from 65.5 to 83.9% while novice attending physicians improved from 66.7 to 81.5% (p < 0.001). The post-course physician confidence scores in using ultrasound significantly increased in all skill categories for both groups. Both trainees and attending physicians demonstrated similar improvement in their post-course test scores and confidence with no statistically significant differences between the groups. The course evaluation scores for overall satisfaction and satisfaction with faculty members' teaching skills were 4.5 and 4.6 on a 5-point scale, respectively., Conclusions: Both novice trainees and attending physicians showed similar improvement in point-of-care ultrasound image interpretation skills and confidence after a brief training course. Although separate training courses have traditionally been developed for attending physicians and trainees, novice learners of point-of-care ultrasound may acquire skills at similar rates, regardless of their ranking as an attending physician or trainee. Future studies are needed to compare the effectiveness of short training courses on image acquisition skills and determine the ideal course design.

Background & Aims: Biliary tract cancers (BTCs) are clinically and pathologically heterogeneous and respond poorly to treatment. Genomic profiling can offer a clearer understanding of their carcinogenesis, classification and treatment strategy. We performed large-scale genome sequencing analyses on BTCs to investigate their somatic and germline driver events and characterize their genomic landscape., Methods: We analyzed 412 BTC samples from Japanese and Italian populations, 107 by whole-exome sequencing (WES), 39 by whole-genome sequencing (WGS), and a further 266 samples by targeted sequencing. The subtypes were 136 intrahepatic cholangiocarcinomas (ICCs), 101 distal cholangiocarcinomas (DCCs), 109 peri-hilar type cholangiocarcinomas (PHCs), and 66 gallbladder or cystic duct cancers (GBCs/CDCs). We identified somatic alterations and searched for driver genes in BTCs, finding pathogenic germline variants of cancer-predisposing genes. We predicted cell-of-origin for BTCs by combining somatic mutation patterns and epigenetic features., Results: We identified 32 significantly and commonly mutated genes including TP53, KRAS, SMAD4, NF1, ARID1A, PBRM1, and ATR, some of which negatively affected patient prognosis. A novel deletion of MUC17 at 7q22.1 affected patient prognosis. Cell-of-origin predictions using WGS and epigenetic features suggest hepatocyte-origin of hepatitis-related ICCs. Deleterious germline mutations of cancer-predisposing genes such as BRCA1, BRCA2, RAD51D, MLH1, or MSH2 were detected in 11% (16/146) of BTC patients., Conclusions: BTCs have distinct genetic features including somatic events and germline predisposition. These findings could be useful to establish treatment and diagnostic strategies for BTCs based on genetic information., Lay Summary: We here analyzed genomic features of 412 BTC samples from Japanese and Italian populations. A total of 32 significantly and commonly mutated genes were identified, some of which negatively affected patient prognosis, including a novel deletion of MUC17 at 7q22.1. Cell-of-origin predictions using WGS and epigenetic features suggest hepatocyte-origin of hepatitis-related ICCs. Deleterious germline mutations of cancer-predisposing genes were detected in 11% of patients with BTC. BTCs have distinct genetic features including somatic events and germline predisposition., (Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Conflicting findings have been reported regarding the role of adiponectin in asthma. The aim of this study was to evaluate the association of adiponectin with pulmonary functions and asthma in the Japanese population. First, among a general population that participated in a previous study (group 1), we selected 329 subjects after excluding those with asthma, chronic obstructive pulmonary disease, and a smoking history and examined the associations of the serum total adiponectin levels with pulmonary functions. In a second cohort (group 2) consisting of 61 asthmatic patients and 175 control non-asthmatic subjects, we examined the associations between asthma and the levels of total, high (HMW), middle (MMW) and low (LMW) molecular weight adiponectin isoforms as well as the ratio of each isoform to total adiponectin level. Although the total adiponectin levels were not significantly different between the asthmatic and control subjects in group 2, the levels were significantly and positively associated with the forced expiratory volume in 1 s after adjustments for confounding factors (P < 0.05) in women in group 1. In group 2, the LMW adiponectin level was significantly higher and the MMW/total adiponectin ratio was significantly lower among the asthmatic subjects than among the control subjects after adjustments for confounding factors in both sexes (P < 0.05). The present study showed that a low total adiponectin level may lead to airway narrowing compatible with asthmatic airways in women, and higher LMW adiponectin levels and lower MMW/total adiponectin ratio are significantly associated with current asthma in both sexes.

Purpose: Spontaneous reported adverse drug reactions (ADRs) are currently the main source of pharmacovigilance activities in each country. The number of ADRs reported to the authority warns of safety risks to patients, but it also reflects the efficiency and limitations of the reporting system itself. This article explored how the accumulation of safety information, status in foreign countries (e.g., US approval), drug company attributes, and regulatory actions (e.g., early post-marketing phase vigilance; EPPV) were associated with the numbers of spontaneously reported ADRs in Japan., Methods: All serious ADRs for drugs for which the active ingredients or route of administration were approved in Japan from 2000 through 2005 were collected from the national database. The numbers of serious ADRs within the first 2 and 3 years after launch were analyzed using the negative binominal distribution model., Results: The launch lag and the presence of drugs with a similar mode of action were negatively associated with the ADR numbers, but the number of study subjects for the new drug application (NDA) showed no clear association. The number of sales representatives and the implementation of EPPV were positively associated with the ADR numbers., Conclusion: The accumulation of foreign post-market evidence seemed to be more important for drug safety in Japan than was the amount of pre-approval safety data. The positive impacts of sales representatives and EPPV suggested a critical role for drug companies in drug safety and also the importance of considering how best to collect information in local situations with unique regulatory requirements., (Copyright © 2012 John Wiley & Sons, Ltd.)

Objective: We conducted a cross-sectional study to investigate which factors have a significant impact on wheezing and QOL in the elderly of a Japanese local community., Methods: In 2008, 527 participants (250 participants aged 45 to 64 years and 277 participants aged 65 to 88 years) responded to the questionnaire regarding wheezing and disease history. QOL was evaluated by the Short Form-8. The participants underwent airway reversibility testing. The plasma levels of IgE were measured. The plasma levels of N-terminal-pro-B-type natriuretic peptide were measured in twenty-one participants with a history of ischemic heart disease and in thirty-five age-matched participants without that history., Results: Wheezing was reported by 50 (9.5%) participants and was associated with a lower score of QOL. In multivariate analysis, wheezing was associated with sex (OR 3.12, CI 1.10-9.67) and a history of bronchial asthma (OR 22.3, CI 6.50-84.0) among participants aged 45 to 64 years. Among participants aged 65 and over, wheezing was associated with a history of bronchial asthma (OR 4.86, CI 1.39-15.1) and ischemic heart disease (OR 5.12, CI 1.61-15.0). Participants with both a history of ischemic heart disease and wheezing showed higher levels of N-terminal-pro-B-type natriuretic peptide. Airway reversibility was only associated with a history of ischemic heart disease (OR 4.65, CI 1.26-17.6)., Conclusion: It is suggested that bronchial asthma and heart disease are both significant causes of wheezing and affect the QOL in the elderly of a Japanese local community.

Background: Prediction and management of drug safety is a global regulatory issue. Safety-related regulatory actions (SRRAs) are taken mostly when unexpected adverse drug reactions occur. Currently, Japan is reconciled to delayed access to new drugs (ie, launch delay compared to Western countries), but may have been benefiting by free-riding on safety data accumulated in other countries prior to Japanese launch., Objective: To identify factors that are significantly associated with SRRAs, and to discuss the challenges that Japan might have to face with increasing access to new drugs., Methods: The SRRAs of 135 new drugs approved from January 2000 to December 2005 were analyzed to investigate association with launch lag, company and drug characteristics, market size, submission data, and regulatory status. SRRAs were measured in terms of the number of emergency safety information notifications and official safety instructions issued by the Japanese regulatory agency within 3 years after approval. A negative binomial distribution model was used for regression analysis., Results: Longer launch lags and presence of drugs with similar modes of action were associated with fewer SRRAs. Bridging strategy showed increased SRRAs. No significant association was observed between SRRAs and the subject number in clinical data packages. Occurrence of SRRAs was varied among development strategy, preceding products, and regional regulations., Conclusions: The occurrence of SRRAs was associated with the accumulation of both foreign and domestic postmarketing evidence rather than with clinical trial data upon launch. Considering the paradigm shift to simultaneous global drug development and filing for regulatory approval, this study indicates the importance of intensive data collection in the early postmarketing phase and use of safety information in early markets. However, even if we would be sufficiently cautious about safety risks of new drugs, a population that enjoys first-in-class drugs probably has to bear the risks.

Interstitial lung disease (ILD) is a frequently encountered and sometimes life-threatening complication among patients with rheumatoid arthritis (RA). In this study, we aim to clarify the incidence of and risk factors for ILD using a large observational cohort of RA patients. We analyzed the database from a large observational cohort of Japanese RA patients, the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort. We defined as interstitial pneumonia (IP) computed tomography (CT) pattern of nonspecific interstitial pneumonia or diffuse alveolar damage. Newly developed IP was identified from patient reports over 2.5 years (April 2004 to October 2006) and was confirmed by extensive medical record, chest X-ray radiograph, and CT. The raw and age/gender-adjusted incidence of IP were reported. IP risk factors were analyzed using a nested case-control design was employed using conditional logistic regression analysis with a stepwise method. Thirty-seven patients among 5,699 RA patients were diagnosed with newly developed IP, including 18 cases with methotrexate-induced pneumonitis (MTX-IP) and 15 cases with IP associated with RA (RA-IP). The age-adjusted incidence of MTX-IP among total patients, males, and females was 3.775, 6.667, and 1.013 per 1,000 cases, respectively, and of RA-IP among total patients, males, and females was 1.056, 1.452, and 0.677 per 1,000 cases, respectively. Conditional logistic regression analysis after stepwise variable selection identified male gender, increased Japanese version of the Health Assessment Questionnaire (J-HAQ) score, decreased pain visual analog scale (VAS), and elevated erythrocyte sedimentation rate as significant risk factors for MTX-IP, while the only risk factor for RA-IP was male gender. The incidence of and risk factors for IP in RA patients were determined in a large observational cohort of RA patients in Japan.