Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Purpose: This study retrospectively investigated the long-term clinical and radiographic outcomes of a bone-level type, 2-piece, internal connection dental implant system characterized by coronal microthreads. Methods: A total of 872 implants placed in 284 patients were selected from 1,845 implants placed in 691 patients by experienced periodontists at Yonsei University Dental Hospital.These selected implants had been followed up for over 10 years and were included in the present study. A statistical evaluation of implant survival and treatment success, based on changes in marginal bone levels, was conducted using electronic records and consecutively taken radiographs. Results: Over a follow-up period of 12.3±2.0 years, 830 of the 872 implants remained intact, yielding a cumulative survival rate of 95.2% at the implant level and 88.4% at the patient level.The cumulative treatment success rates, characterized by marginal bone loss of less than 2 mm, stood at 87.0% for implants and 76.1% for patients. Among the 830 surviving implants, 113 fixtures were classified as ailing, with an average marginal bone loss of 4.09±1.44 mm.Cox regression analysis revealed that implants 8 mm in length or shorter were significantly more likely to fail or experience pathologic marginal bone resorption, with hazard ratios of 3.71 and 2.00, respectively (P<0.05). Conclusions The survival and treatment success of the investigated microthreaded, bone-level, 2-piece, internal connection implants were acceptable over a follow-up period exceeding 10 years. However, shorter dental implants exhibited a higher propensity for failure and excessive marginal bone loss.

This consensus report presents the first official position statement of the Korean Academy of Periodontology on peri-implant diseases, issued in response to South Korea’s rapidly aging population and the associated rise in peri-implant disease management. It reviews the prevalence, classification, and definition of peri-implant diseases, emphasizing that these conditions progress more aggressively and unpredictably than periodontal diseases.The report also identifies systemic and local risk indicators, diagnostic criteria, and evidencebased treatment protocols for peri-implant mucositis and peri-implantitis, integrating international standards with Korea-specific clinical data. Clinical recommendations include structured maintenance programs, risk-based recall intervals, and patient education, with the goal of reducing disease recurrence and improving long-term implant success.

Purpose: A 12-year-old boy with a five-day history of blunt trauma to the right orbit was referred to our pediatric ophthalmology clinic for evaluation of diplopia and proptosis.Case summary: Upon examination, uncorrected visual acuity was 20/20 in both eyes, intraocular pressures were 19 mmHg and 16 mmHg in the right and left eye, respectively, and Hertel exophthalmometry revealed 2 mm of right eye proptosis. Extraocular motility testing demonstrated 16 prism diopters (PD) of right exotropia and 2 PD of right hypotropia in primary position, with restricted upgaze in the right eye. Pupillary reflexes, color vision, slit-lamp biomicroscopy, and fundus examination were normal. Orbital computed tomography (CT) showed a subperiosteal hematoma compressing the right superior rectus muscle. The patient was managed conservatively, with resolution of upgaze limitation within six months. Follow-up CT at nine months demonstrated complete hematoma resolution without residual orbital mass. Conclusions Spontaneous resolution of post-traumatic orbital subperiosteal hematoma is rare but possible; in the absence of compressive optic neuropathy, careful observation with regular follow-up should be considered.

Purpose: To investigate the prevalence ratio of primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) in the Asian population. Methods: Systematic searches of PubMed, Embase, and Cochrane databases for population-based studies in Asia published until August 5, 2022. We conducted a meta-analysis for PACG to POAG prevalence ratio using inverse variance–weighted random-effects meta-analyses so as to combine the study-specific measures of association. Between-study outcome variation (i.e., heterogeneity) was quantified with the I2 statistic. The multiple meta-regression analyses were performed in order to further account for the reasons for heterogeneity. Results: Twenty studies, with a total study population of 52,522 individuals, had been conducted in 13 countries. The pooled PACG to POAG prevalence ratio was 2.204 (95% confidence interval, 1.617–3.004) with high heterogeneity (p < 0.001). In multiple meta-regression model, prevalence of POAG is the most important predictor for heterogeneity (model importance, 0.954), followed continent (0.508), and publication year (0.222). For every additional elevation of POAG prevalence (i.e., increase of 1.0%), the PACG to POAG prevalence ratio is expected to rise by 0.471. Conclusions We estimated the pooled PACG to POAG prevalence ratio in the Asian population. The POAG prevalence is the most important factor to determine the PACG to POAG prevalence ratio.

Gastritis is a disease characterized by inflammation of the gastric mucosa. It is very common and has various classification systems such as the updated Sydney system. As there is a lot of evidence that Helicobacter pylori infection is associated with the development of gastric cancer and that gastric cancer can be prevented by eradication, H. pylori gastritis has been emphasized recently. The incidence rate of gastric cancer in Korea is the highest in the world, and due to the spread of screening endoscopy, atrophic gastritis and intestinal metaplasia are commonly diagnosed in the general population. However, there have been no clinical guidelines developed in Korea for these lesions. Therefore, this clinical guideline has been developed by the Korean College of Helicobacter and Upper Gastrointestinal Research for important topics that are frequently encountered in clinical situations related to gastritis. Evidence-based guidelines were developed through systematic review and de novo processes, and eight recommendations were made for eight key questions. This guideline needs to be periodically revised according to the needs of clinical practice or as important evidence about this issue is published in the future.