COVID-19 Vaccine-Associated Pneumonitis in the Republic of Korea: A Nationwide Multicenter Survey.

BACKGROUND: Recent reports have suggested that pneumonitis is a rare complication following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, its clinical features and outcomes are not well known. The aim of this study was to identify the clinical characteristics and outcomes of patients with vaccine-associated pneumonitis following vaccination against SARS-CoV-2. METHODS: In this nationwide multicenter survey study, questionnaires were distributed to pulmonary physicians in referral hospitals. They were asked to report cases of development or exacerbation of interstitial lung disease (ILD) associated with the coronavirus disease 2019 vaccine. Vaccine-associated pneumonitis was defined as new pulmonary infiltrates documented on chest computed tomography within 4 weeks of vaccination and exclusion of other possible etiologies. RESULTS: From the survey, 49 cases of vaccine-associated pneumonitis were identified between February 27 and October 30, 2021. After multidisciplinary discussion, 46 cases were analyzed. The median age was 66 years and 28 (61%) were male. The median interval between vaccination and respiratory symptoms was 5 days. There were 20 (43%), 17 (37%), and nine (19%) patients with newly identified pneumonitis, exacerbation of pre-diagnosed ILD, and undetermined pre-existing ILD, respectively. The administered vaccines were BNT162b2 and ChAdOx1 nCov-19/AZD1222 each in 21 patients followed by mRNA-1273 in three, and Ad26.COV2.S in one patient. Except for five patients with mild disease, 41 (89%) patients were treated with corticosteroid. Significant improvement was observed in 26 (57%) patients including four patients who did not receive treatment. However, ILD aggravated in 9 (20%) patients despite treatment. Mortality was observed in eight (17%) patients. CONCLUSION: These results suggest pneumonitis as a potentially significant safety concern for vaccines against SARS-CoV-2. Clinical awareness and patient education are necessary for early recognition and prompt management. Additional research is warranted to identify the epidemiology and characterize the pathophysiology of vaccine-associated pneumonitis.

New prognostic scoring system for mortality in idiopathic pulmonary fibrosis by modifying the gender, age, and physiology model with desaturation during the six-minute walk test.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial lung disease (ILD) with variable and heterogeneous clinical course. The GAP (gender, age, and physiology) model had been used to predict mortality in patients with IPF, but does not contain exercise capacity. Therefore, our aim in this study was to develop new prognostic scoring system in the Korea IPF Cohort (KICO) registry. Materials and methods: This is a retrospective study of Korean patients with IPF in KICO registry from June 2016 to August 2021. We developed new scoring system (the GAP6) based on the GAP model adding nadir saturation of percutaneous oxygen (SpO2) during six-minute walk test (6MWT) in the KICO registry and compared the efficacy of the GAP and the GAP6 model. Results: Among 2,412 patients in KICO registry, 966 patients were enrolled. The GAP6 model showed significant prognostic value for mortality between each stage [HR Stage II vs. Stage I = 2.89 (95% CI = 2.38-3.51), HR Stage III vs. Stage II = 2.68 (95% CI = 1.60-4.51)]. In comparison the model performance with area under curve (AUC) using receiver operating characteristic (ROC) curve analysis, the GAP6 model showed a significant improvement for predicting mortality than the GAP model (AUC the GAP vs. the GAP6, 0.646 vs. 0.671, p < 0.0019). Also, the C-index values slightly improved from 0.674 to 0.691 for mortality. Conclusion: The GAP6 model adding nadir SpO2 during 6WMT for an indicator of functional capacity improves prediction ability with C-index and AUC. Additional multinational study is needed to confirm these finding and validate the applicability and accuracy of this risk assessment system.

Successful mRNA COVID-19 Vaccination and Colonoscopy After Oral Desensitization in a Patient With Polyethylene Glycol Allergy.

Anaphylaxis to polyethylene glycol (PEG) is rare and mainly occurs with the use of laxatives containing PEG. Recently, an increasing number of PEG allergies have been reported, particularly those related to coronavirus disease 2019 (COVID-19) vaccines. mRNA COVID-19 vaccines, such as the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) vaccines, contain PEG2000 as an excipient and are contraindicated when allergy to a vaccine component exist. We report a 55-year-old woman's history as a case of successful mRNA COVID-19 vaccination and colonoscopy after oral desensitization to PEG in a patient with PEG allergy who required both COVID-19 vaccination and colon evaluation. Allergy to PEG was diagnosed based on clinical history, skin test results, and basophil histamine release testing. Oral desensitization effectively suppressed histamine release from basophils in response to PEG stimulation, suggesting that oral desensitization using PEG-based laxatives may be an effective treatment option for patients with allergy to the substance.

Clinical Features, Diagnosis, Management, and Outcomes of Idiopathic Pulmonary Fibrosis in Korea: Analysis of the Korea IPF Cohort (KICO) Registry.

BACKGROUND: The Korea Interstitial Lung Disease Study Group has made a new nationwide idiopathic pulmonary fibrosis (IPF) registry because the routine clinical practice has changed due to new guidelines and newly developed antifibrotic agents in the recent decade. The aim of this study was to describe recent clinical characteristics of Korean IPF patients. METHODS: Both newly diagnosed and following IPF patients diagnosed after the previous registry in 2008 were enrolled. Survival analysis was only conducted for patients diagnosed with IPF after 2016 because antifibrotic agents started to be covered by medical insurance of Korea in October 2015. RESULTS: A total of 2,139 patients were analyzed. Their mean age at diagnosis was 67.4±9.3 years. Of these patients, 76.1% were males, 71.0% were ever-smokers, 14.4% were asymptomatic at the time of diagnosis, and 56.9% were at gender-agephysiology stage I. Occupational toxic material exposure was reported in 534 patients. The mean forced vital capacity was 74.6% and the diffusing capacity for carbon monoxide was 63.6%. Treatment with pirfenidone was increased over time: 62.4% of IPF patients were treated with pirfenidone initially. And 79.2% of patients were treated with antifiboritics for more than three months during the course of the disease since 2016. Old age, acute exacerbation, treatment without antifibrotics, and exposure to wood and stone dust were associated with higher mortality. CONCLUSION: In the recent Korean IPF registry, the percentage of IPF patients treated with antifibrotics was increased compared to that in the previous IPF registry. Old age, acute exacerbation, treatment without antifibrotics, and exposure to wood and stone dust were associated with higher mortality.

Low-level expression of necroptosis factors indicates a poor prognosis of the squamous cell carcinoma subtype of non-small-cell lung cancer.

BACKGROUND: The programmed cell death pathway necroptosis may synergize with the DNA damage response (DDR) in opposing tumor progression. While our basic mechanistic understanding of the necroptotic cell death advances rapidly, its prognostic implications have not been thoroughly examined in cancers. METHODS: We included 394 patients with stage I non-small-cell lung cancer (NSCLC) who underwent surgical tumor resection between 1 January 1997 and 31 December 2011 and measured expression levels of nine proteins involved in necroptosis and the DDR in primary samples from 394 patients using tissue microarray. Protein expression evaluated by using an H-score method was dichotomized by the median value. The overall survival as the endpoint was calculated from the time of diagnosis to the time of the last follow-up or death. RESULTS: We find that low-level expression of the necroptosis markers RIPK3 and PELI1 is associated with high risk of patient death. High-level expression of the key DDR factor p53 in combination with low-level expression of either RIPK3 or PELI1 increases the risk further. These gene expression effects appear to occur specifically in the squamous cell carcinoma (SCC) subtype of stage I NSCLC, while not observed in the non-SCC subtypes. CONCLUSIONS: Low-level expression of such necroptosis factors as RIPK3 and PELI1 in combination with high-level expression of the DDR factor p53 can serve as a critical indicator in predicting survival of stage I NSCLC patients with the SCC subtype.

Longitudinal Changes in Clinical Features, Management, and Outcomes of Idiopathic Pulmonary Fibrosis. A Nationwide Cohort Study.

Rationale: In recent decades, diagnosis and treatment recommendations for idiopathic pulmonary fibrosis (IPF) have changed. In Korea, the average life expectancy has increased, unmet healthcare needs have been reduced, and the number of computed tomographic examinations performed has nearly doubled. The Korean Interstitial Lung Disease Study Group conducted a nationwide cohort study for idiopathic interstitial pneumonia, including IPF, and established a registry for IPF.Objectives: Using study data collected by the study group, this study aimed to evaluate longitudinal changes in clinical features, diagnosis, treatment, and mortality and analyze the extent to which changes in medication usage affected IPF-associated mortality.Methods: The study population included newly diagnosed patients with IPF from a cohort study (January 2002 to September 2008, n = 1,839, 2008 group) and prospective registry (January 2012 to August 2018, n = 1,345, 2018 group). Survival curves were estimated using the Kaplan-Meier method, and Cox regression models were used to identify mortality-associated risk factors in each group.Results: The 2018 group was younger, had fewer symptoms, had less honeycombing, underwent more serologic autoimmune marker and pulmonary function tests, had higher oxygen partial pressure and lower carbon dioxide partial pressure values, was less frequently diagnosed by surgical biopsy, and had better survival than the 2008 group. Steroid use and conservative care declined, whereas N-acetylcysteine use increased in this group. Antifibrotic agents were used in only the 2018 group. In the 2008 group, N-acetylcysteine was associated with lower mortality, whereas conservative care was associated with higher mortality. In the 2018 group, the use of antifibrotic agents was associated with lower mortality, and steroid use was associated with higher mortality. The survival rates in the 2008 and 2018 non-antifibrotic agent subgroups were similar.Conclusions: This study analyzed national IPF cohort data spanning 17 years. In clinical practice, the IPF diagnosis was made earlier, steroid and immunosuppressive agent use was reduced, and antifibrotic agents were administered. The survival of patients with IPF has improved over the decades, and antifibrotic use was consistently associated with improved survival.Clinical trial registered with clinicaltrials.gov (NCT04160715).

An unusual case of herpes simplex virus pneumonia with cavitary and necrotic changes.

Ground glass opacities, consolidation, and pleural effusions are observed in herpes simplex virus (HSV) pneumonia. Neither necrosis nor cavitation has been reported in areas of parenchymal disease. We describe a case of HSV pneumonia with unusual multiple cavitary and necrotic changes in an immunocompetent person. To our knowledge, this is the first reported case of HSV pneumonia with multiple cavitary and necrotic changes in areas of consolidation and nodules.

Diagnosis of pulmonary cement embolism using only the bone window setting on computed tomography: a case report.

Pulmonary cement embolism (PCE) is one of several complications of percutaneous vertebroplasty and kyphoplasty. Generally, PCE can be easily diagnosed based on typical chest radiograph findings such as single or multiple radiographically dense opacities with a tubular or branch shape in the lung field along with a recent history of percutaneous vertebroplasty or kyphoplasty. These findings can be alarming and may be encountered on routine chest radiographs, even in asymptomatic patients. One study showed that PCEs that were not visualized on chest radiograph were also not shown on chest computed tomography. However, we encountered a patient with dyspnea who had normal chest radiograph findings but was diagnosed with PCE through only the bone window setting on chest computed tomography. The present case will be beneficial to all physicians examining older patients with dyspnea.

Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases: Part 1. Introduction.

Idiopathic interstitial pneumonia (IIP) is a histologically identifiable pulmonary disease without a known cause that usually infiltrates the lung interstitium. IIP is largely classified into idiopathic pulmonary fibrosis, idiopathic non-specific interstitial pneumonia, respiratory bronchiolitis-interstitial lung disease (ILD), cryptogenic organizing pneumonia, desquamative interstitial pneumonia, and acute interstitial pneumonia. Each of these diseases has a different prognosis and requires specific treatment, and a multidisciplinary approach that combines chest high-resolution computed tomography (HRCT), histological findings, and clinical findings is necessary for their diagnosis. Diagnosis of IIP is made based on clinical presentation, chest HRCT findings, results of pulmonary function tests, and histological findings. For histological diagnosis, video-assisted thoracoscopic biopsy and transbronchial lung biopsy are used. In order to identify ILD associated with connective tissue disease, autoimmune antibody tests may also be necessary. Many biomarkers associated with disease prognosis have been recently discovered, and future research on their clinical significance is necessary. The diagnosis of ILD is difficult because patterns of ILD are both complicated and variable. Therefore, as with other diseases, accurate history taking and meticulous physical examination are crucial.

Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases: Part 2. Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia, which presents with a progressive worsening dyspnea, and thus a poor outcome. The members of the Korean Academy of Tuberculosis and Respiratory Diseases as well as the participating members of the Korea Interstitial Lung Disease Study Group drafted this clinical practice guideline for IPF management. This guideline includes a wide range of topics, including the epidemiology, pathogenesis, risk factors, clinical features, diagnosis, treatment, prognosis, and acute exacerbation of IPF in Korea. Additionally, we suggested the PICO for the use of pirfenidone and nintendanib and for lung transplantation for the treatment of patients with IPF through a systemic literature review using experts' help in conducting a meta-analysis. We recommend this guideline to physicians, other health care professionals, and government personnel in Korea, to facilitate the treatment of patients with IPF.

Case of both rivaroxaban- and dabigatran-induced leukocytoclastic vasculitis, during management of pulmonary thromboembolism.

Leukocytoclastic vasculitis is a disorder characterized by neutrophilic inflammation that is predominantly limited to the superficial cutaneous postcapillary venules. This condition may be idiopathic or may have a defined cause. Rivaroxaban and dabigatran have been widely used as warfarin alternatives, because of their efficacy and safety. In this case report, we describe a case of leukocytoclastic vasculitis induced by both rivaroxaban- and dabigatran-, which developed during the management of pulmonary thromboembolism.

Small-cell Lung Cancer Presenting as Fatal Pulmonary Hemorrhage.

Small-cell lung cancer (SCLC) is a lung cancer histological subtype unusual in its favorable response to cytotoxic chemotherapy. Life-threatening manifestations at presentation are rarely reported and should be an important clinical concern. We report a case of a 63-year-old man presenting with rapid-onset refractory severe thrombocytopenia, development of massive hemoptysis, and death from respiratory failure. This case provides clinicians a reference for this unusual presentation and carries clinical implications for managing SCLC patients.

Comparison of CPI and GAP models in patients with idiopathic pulmonary fibrosis: a nationwide cohort study.

The clinical course of idiopathic pulmonary fibrosis (IPF) is difficult to predict, partly owing to its heterogeneity. Composite physiologic index (CPI) and gender-age-physiology (GAP) models are easy-to-use predictors of IPF progression. This study aimed to compare the predictive values of these two models. From 2003 to 2007, the Korean Interstitial Lung Disease (ILD) Study Group surveyed ILD patients using the 2002 ATS/ERS criteria. A total of 832 patients with IPF were enrolled in this study. CPI was calculated as follows: 91.0 - (0.65 × %DLCO) - [0.53 × %FVC + [0.34 × %FEV1. GAP stage was calculated based on gender (0-1 points), age (0-2 points), and two physiologic lung function parameters (0-5 points). The two models had similar significant predictive values for patients with IPF (p < 0.001). The area under the curve (AUC) was higher for CPI than GAP for prediction of 1-, 2-, and 3-year mortality in this study. The AUC was higher for surgically diagnosed IPF patients than for clinically diagnosed patients. However, neither CPI nor GAP yielded good predictions of outcomes; the AUC was approximately 0.61~0.65. Although both CPI and GAP stage are significantly useful predictors for IPF, they have limited capability to accurately predict outcomes.

Dramatic response of acute disseminated intravascular coagulation to erlotinib in a patient with lung adenocarcinoma with activating EGFR mutation.

Disseminated intravascular coagulation (DIC) is a commonly encountered clinical situation characterized by thrombotic occlusion or bleeding in patients with lung cancer. DIC in patients with cancer is usually asymptomatic, taking a chronic form as a compensatory mechanism. Although acute DIC in patients with lung cancer is rarely reported, it can be fatal. We herein describe a patient with lung adenocarcinoma with an activating mutation of the epidermal growth factor receptor (EGFR) gene who developed acute DIC after minor surgical excision. The patient's condition dramatically improved immediately after administration of erlotinib. This report alerts physicians to the occurrence of acute DIC and serves as a reference in treating EGFR mutation-positive lung cancer in patients with DIC.

Factors affecting treatment outcome in patients with idiopathic nonspecific interstitial pneumonia: a nationwide cohort study.

BACKGROUND: The effects of corticosteroid-based therapy in patients with idiopathic nonspecific interstitial pneumonia (iNSIP), and factors affecting treatment outcome, are not fully understood. We aimed to investigate the long-term treatment response and factors affecting the treatment outcome in iNSIP patients from a multi-center study in Korea. METHODS: The Korean interstitial lung disease (ILD) Study Group surveyed ILD patients from 2003 to 2007. Patients were divided into two groups to compare the treatment response: response group (forced vital capacity (FVC) improves ≥10% after 1 year) and non-response group (FVC <10%). Factors affecting treatment response were evaluated by multivariate logistic regression analysis. RESULTS: A total of 261 patients with iNSIP were enrolled, and 95 patients were followed-up for more than 1 year. Corticosteroid treatment was performed in 86 patients. The treatment group showed a significant improvement in lung function after 1-year: FVC, 10.0%; forced expiratory volume (FEV1), 9.8%; diffusing capacity of the lung for carbon monoxide (DLco), 8.4% (p < 0.001). Sero-negative anti-nuclear antibody (ANA) was significantly related with lung function improvement. Sero-positivity ANA was significantly lower in the response group (p = 0.013), compared to that in the non-response group. A shorter duration of respiratory symptoms at diagnosis was significantly associated with a good response to treatment (p = 0.018). CONCLUSION: Treatment with corticosteroids and/or immunosuppressants improved lung function in iNSIP patients, which was more pronounced in sero-negative ANA and shorter symptom duration patients. These findings suggest that early treatment should be considered in iNSIP patients, even in an early disease stage.

Clinical significance of cigarette smoking and dust exposure in pulmonary alveolar proteinosis: a Korean national survey.

BACKGROUND: This study aimed to investigate clinical characteristics of Korean PAP patients and to examine the potential risk factors of PAP. METHODS: We retrospectively reviewed medical records of 78 Korean PAP patients diagnosed between 1993 and 2014. Patients were classified into two groups according to the presence/absence of treatment (lavage). Clinical and laboratory features were compared between the two groups. RESULTS: Of the total 78 PAP patients, 60% were male and median age at diagnosis was 47.5 years. Fifty three percent were ever smokers (median 22 pack-years) and 48% had a history of dust exposure (metal 26.5%, stone or sand 20.6%, chemical or paint 17.7%, farming dust 14.7%, diesel 14.7%, textile 2.9%, and wood 2.9%). A history of cigarette smoking or dust exposure was present in 70.5% of the total PAP patients, with 23% having both of them. Patients who underwent lavage (n = 38) presented symptoms more frequently (38/38 [100%] vs. 24/40 [60%], P < 0.001) and had significantly lower PaO2 and DLCO with higher D(A-a)O2 at the onset of disease than those without lavage (n = 40) (P = 0.006, P < 0.001, and P = 0.036, respectively). Correspondingly, the distribution of disease severity score (DSS) differed significantly between the two groups (P = 0.001). Based on these, when the total patients were categorized according to DSS (low DSS [DSS 1-2] vs. high DSS [DSS 3-5]), smoking status differed significantly between the two groups with the proportion of current smokers significantly higher in the high DSS group (11/22 [50%] vs. 7/39 [17.9%], P = 0.008). Furthermore, current smokers had meaningfully higher DSS and serum CEA levels than non-current smokers (P = 0.011 and P = 0.031), whereas no difference was found between smokers and non-smokers. Regarding type of exposed dust, farming dust was significantly associated with more severe form of PAP (P = 0.004). CONCLUSION: A considerable proportion of PAP patients had a history of cigarette smoking and/or dust exposure, suggestive of their possible roles in the development of PAP. Active cigarette smoking at the onset of PAP is associated with the severity of PAP.

Prognostic impact of a new score using neutrophil-to-lymphocyte ratios in the serum and malignant pleural effusion in lung cancer patients.

BACKGROUNDS: Various studies have reported that the neutrophil-to-lymphocyte ratio in the serum (sNLR) may serve as a cost-effective and useful prognostic factor in patients with various cancer types. However, no study has reported the prognostic impact of the NLR in malignant pleural effusion (MPE). To address this gap, we investigated the clinical impact of NLR as a prognostic factor in MPE (mNLR) and a new scoring system that use NLRs in the serum and MPE (smNLR score) in lung cancer patients. METHODS: We retrospectively reviewed all of the patients who were diagnosed with lung cancer and who presented with pleural effusion. To maintain the quality of the study, only patients with malignant cells in the pleural fluid or tissue were included. The patients were classified into three smNLR score groups, and clinical variables were investigated for their correlation with survival. RESULTS: In all, 158 patients were classified into three smNLR score groups as follows: 84 (53.2%) had a score of 0, 58 (36.7%) had a score of 1, and 16 (10.1%) had a score of 2. In a univariate analysis, high sNLR, mNLR, and increments of the smNLR score were associated with shorter overall survival (p < 0.001, p = 0.004, and p < 0.001, respectively); moreover, age, Eastern Cooperative Oncology Group performance status (ECOG PS), histology, M stage, hemoglobin level, albumin level, and calcium level were significant prognostic factors. A multivariable analysis confirmed that ECOG PS (p < 0.001), histology (p = 0.001), and smNLR score (p < 0.012) were independent predictors of overall survival. CONCLUSIONS: The new smNLR score is a useful and cost-effective prognostic factor in lung cancer patients with MPE. Although further studies are required to generalize our results, this information will benefit clinicians and patients in determining the most appropriate therapy for patients with MPE.

Predicting survival of patients with idiopathic pulmonary fibrosis using GAP score: a nationwide cohort study.

BACKGROUND: The clinical course of idiopathic pulmonary fibrosis (IPF) varies widely. Although the GAP model is useful for predicting mortality, survivals have not yet been validated for each GAP score. We aimed to elucidate how prognosis is related to GAP score and GAP stage in IPF patients. METHODS: The Korean Interstitial Lung Disease Study Group conducted a national survey to evaluate various characteristics in IPF patients from 2003 to 2007. Patients were diagnosed according to the 2002 criteria of the ATS/ERS. We enrolled 1,685 patients with IPF; 1,262 had undergone DLCO measurement. Patients were stratified based on GAP score (0-7): GAP score Group 0 (n = 26), Group 1 (n = 150), Group 2 (n = 208), Group 3 (n = 376), Group 4 (n = 317), Group 5 (n = 138), Group 6 (n = 39), and Group 7 (n = 8). RESULTS: Higher GAP score and GAP stage were associated with a poorer prognosis (p < 0.001, respectively). Survival time in Group 3 was lower than those in Groups 1 and 2 (p = 0.043 and p = 0.039, respectively), and higher than those in groups 4, 5, and 6 (p = 0.043, p = 0.032, and p = 0.003, respectively). Gender, age, and DLCO (%) differed significantly between Groups 2 and 3. All four variables in the GAP model differed significantly between Groups 3 and 4. CONCLUSION: The GAP system showed significant predictive ability for mortality in IPF patients. However, prognosis in IPF patients with a GAP score of 3 were significantly different from those in the other stage I groups and stage II groups of Asian patients.

Airway centered invasive pulmonary aspergillosis in an immunocompetent patient: case report and literature review.

Invasive pulmonary aspergillosis is a major problem that occurs in severely immunocompromised patients. Airway centered invasive pulmonary aspergillosis is rare in patients with normal immunity or those without critical illness. Computed tomography (CT) is a very useful diagnostic modality, yielding characteristic imaging findings for early diagnosis of this infection in immunocompromised and immunocompetent patients. We describe the case of an immunocompetent patient with airway centered invasive aspergillosis, who was successfully treated with voriconazole.

Comparisons of Prognosis between Surgically and Clinically Diagnosed Idiopathic Pulmonary Fibrosis Using Gap Model: A Korean National Cohort Study.

Although a multidisciplinary approach has become an important criterion for an idiopathic pulmonary fibrosis (IPF) diagnosis, lung biopsies remain crucial. However, the prognosis of patients with surgically diagnosed IPF (sIPF) is uncertain. We aimed to investigate the prognosis of patients with clinically diagnosed IPF (cIPF) and sIPF. In this retrospective observational study, the Korean Interstitial Lung Disease Study Group conducted a national survey to evaluate the clinical, physiological, radiological, and survival characteristics of patients with IPF from January 1, 2003 to December 31, 2007. Patients were recruited from 54 universities and teaching hospitals across the Republic of Korea. IPF diagnoses were established according to the 2002 American Thoracic Society (ATS)/European Respiratory Society criteria (ERS) guideline. A total of 1685 patients with IPF (1027 cIPF and 658 sIPF) were enrolled. Patients with sIPF were significantly younger, predominantly female, and nonsmokers (all P < 0.001). sIPF group had significantly better initial pulmonary function. The proportion of computed tomography-based honeycomb findings of patients with cIPF was higher than in those with sIPF (P < 0.001). A Kaplan-Meier analysis showed that the sIPF group had a better prognosis (P = 0.001). A survival analysis showed that age, pulmonary function parameters, pulmonary oxygen tension, honeycombing change, and combined lung cancer had a significant influence on patient prognosis. However, there was no significant difference in prognosis between the cIPF and sIPF groups after adjusting for GAP (gender, age, physiology) stage. The patients with sIPF had better clinical features than those with cIPF. However, after adjusting for GAP stage, the sIPF group showed similar prognoses as the cIPF group. This study showed that after adjusting for GAP stage, the prognosis of patients with IPF is the same regardless of the diagnostic method used.