• Journal of Korean Neurosurgical Society
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• v.59 no.1
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• pp.11-16
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• 2016

Objective : We conducted a retrospective cohort study to elucidate the natural course of unruptured intracranial aneurysms (UIAs) at a single institution. Methods : Data from patients diagnosed with UIA from March 2000 to May 2008 at our hospital were subjected to a retrospective analysis. The cumulative and annual aneurysm rupture rates were calculated. Additionally, risk factors associated with aneurysmal rupture were identified. Results : A total of 1339 aneurysms in 1006 patients met the inclusion criteria. During the follow-up period, 685 aneurysms were treated before rupture via either an open surgical or endovascular procedure. Six hundred fifty-four UIAs were identified and not repaired during the follow-up period. The mean UIA size was $4.5{\pm}3.2mm$, and 86.5% of the total UIAs had a largest dimension <7 mm. Among these UIAs, 18 ruptured at a median of 1.6 years (range : 27 days to 9.8 years) after day 0. The annual rupture risk during a 9-year follow-up was 1.00%. A multivariate Cox proportional hazards analysis revealed that the aneurysm size and a history of subarachnoid hemorrhage (SAH) were statistically significant risk factors for rupture. For an aneurysms smaller than 7 mm in the absence of a history of SAH, the annual rupture risk was 0.79%. Conclusion : In our study, the annual rupture risk for UIAs smaller than 7 mm in the absence of a history of SAH was higher than that of Western populations but similar to that of the Japanese population.

• 대한예방의학회:학술대회논문집
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• 2005.10a
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• pp.434-434
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• 2005

• Safety and Health at Work
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• v.13 no.2
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• pp.135-140
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• 2022

Background: Coal mining is a hazardous industry. The purpose of the study is to identify the nature of occupational injuries and diseases among coal miners and to determine the factors that affect the rate of injury and duration of time loss from work. Methods: A retrospective cohort study was conducted using accepted workers' compensation claims data of 30,390 Australian coal miners between July 2003 and June 2017. Results: Musculoskeletal and fracture conditions accounted for approximately 60% of claims in all occupational groups. Cox regression analysis showed that older age and female gender were significant predictors of longer time off work. Injury types and occupations were associated with work time loss: mental health conditions, and machine operators and drivers had significantly longer durations of time off work. Conclusion: Future research can further address how these factors led to longer time off work so that coal industry regulators, employers, and healthcare providers can target interventions more effectively to these at-risk workers.

• The Korean Journal of Pain
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• v.33 no.2
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• pp.144-152
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• 2020

Background: Hemidiaphragmatic paralysis, a frequent complication of the brachial plexus block performed above the clavicle, is rarely associated with an infraclavicular approach. The costoclavicular brachial plexus block is emerging as a promising infraclavicular approach. However, it may increase the risk of hemidiaphragmatic paralysis because the proximity to the phrenic nerve is greater than in the classical infraclavicular approach. Methods: This retrospective analysis compared the incidence of hemidiaphragmatic paralysis in patients undergoing costoclavicular and supraclavicular brachial plexus blocks. Of 315 patients who underwent brachial plexus block performed by a single anesthesiologist, 118 underwent costoclavicular, and 197 underwent supraclavicular brachial plexus block. Propensity score matching selected 118 pairs of patients. The primary outcome was the incidence of hemidiaphragmatic paralysis, defined as a postoperative elevation of the hemidiaphragm > 20 mm. Factors affecting the incidence of hemidiaphragmatic paralysis were also evaluated. Results: Hemidiaphragmatic paralysis was observed in three patients (2.5%) who underwent costoclavicular and 47 (39.8%) who underwent supraclavicular brachial plexus blocks (P < 0.001; odds ratio, 0.04; 95% confidence interval, 0.01-0.13). Both the brachial plexus block approach and the injected volume of local anesthetic were significantly associated with hemidiaphragmatic paralysis. Conclusions: The incidence of hemidiaphragmatic paralysis is significantly lower with costoclavicular than with supraclavicular brachial plexus block.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.203-207
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• 2005

Objectives: Recently, the American Diabetes Association (ADA) redefined the criteria of prediabetes, which has lowered the diagnostic level of fasting plasma glucose (FPG) from 110 to 125 mg/dl, down to levels between 100 to 125mg/dl. The purpose of this study was to determine the predictive cutoff level of FPG as a risk for the development of diabetes mellitus in Korean men. Methods: A retrospective cohort study was conducted on 11,423 (64.5%) out of 17,696 males $\leq$30 years of age, and who met the FPG of $\leq$125 mg/dl and hemoglobin A1c of $\leq$ 6.4% criteria, without a history of diabetes, and who were enrolled at the screening center of a certain university hospital between January and December 1999. The subjects were followed from January 1999 to December 2002 (mean follow-up duration; 2.3(${\pm}0.7$) years). They were classified as normal (FPG <100mg/dl), high glucose (FPG $\geq$100mg/dl and <110mg/dl) and impaired fasting glucose (FPG $\geq$110mg/dl and $\leq$125mg/dl) on the basis of their fasting plasma glucose level measured in 1999. We compared the incidence of diabetes between the 3 groups by performing Cox proportional hazards model and used receiver operating characteristic analyses of the FPG level, in order to estimate the optimal cut-off values as predictors of incident diabetes. Results: At the baseline, most of the study subjects were in age in their 30s to 40s (mean age, 41.8(${\pm}7.1$) year). The incidence of diabetes mellitus in this study was 1.19 per 1,000 person-years (95% CI=0.68-1.79), which was much lower than the results of a community-based study that was 5.01 per 1,000 person-years. The relative risks of incident diabetes in the high glucose and impaired fasting glucose groups, compared with the normal glucose group, were 10.3 (95% CI=2.58-41.2) and 95.2 (95% CI= 29.3-309.1), respectively. After adjustment for age, body mass index, and log triglyceride, a FPG greater than 100mg/dl remained significant predictors of incident diabetes. Using the receiver operating characteristic (ROC) curve, the optimal cutoff level of FPG as a predictor of incident diabetes was 97.5 mg/dl, with a sensitivity and a specificity of 81.0% and 86.0%, respectively. Conclusion: These results suggest that lowering the criteria of impaired fasting glucose is needed in Korean male adults. Future studies on community-based populations, including women, will be required to determine the optimal cutoff level of FPG as a predictor of incident diabetes.

• Korean Journal of Clinical Pharmacy
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• v.29 no.3
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• pp.186-192
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• 2019

Background: Diabetes is associated with cancer risk in the aging population. Observational studies have indicated the beneficial effects of metformin against breast cancer, making studies on the anticancer potential of antidiabetic drugs worthwhile. This study investigated cancer incidence in patients on antidiabetic monotherapy. Methods: Using National Health Insurance Service data (2002-2013), a retrospective cohort study that included type 2 diabetes mellitus (T2DM) patients was conducted. Study subjects were enrolled if they were ${\geq}30$ years old, on monotherapy for diabetes, and cancer-free. They were followed up for cancer occurrence or death, until December 31st, 2013. A Cox proportional hazard model analysis was conducted between metformin and sulfonylurea (including meglitinide) users, to determine cancer risk, with adjustment for age, gender, comorbidity index, dyslipidemia, hypertension, and T2DM duration. Results: The number of antidiabetic monotherapy-treated T2DM patients without a history of cancer was 9,554 (metformin, n = 5,825; sulfonylurea, n = 3,225; others, n = 504). During the follow-up period (mean, 2.04; IQR, 3.18 years), the cancer incidence rate was 5.48/100 and 5.45/100 patient-years for metformin and sulfonylurea, respectively. The hazard ratio (HR) for risk of cancer incidence in the metformin group was 0.74 (95% confidence interval [CI], 0.66-0.83; p < 0.0001), compared with sulfonylurea. Additionally, the HRs for risks of lung, liver, and stomach cancer were respectively 0.46 (95% CI, 0.31-0.66; p < 0.0001), 0.41 (95% CI, 0.31-0.54; p < 0.0001), and 0.51 (95% CI, 0.35-0.73; p = 0.0003). Conclusion: Antidiabetic therapy with metformin reduces cancer risk by 26%, specifically for lung, liver, and stomach cancer.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.115-124
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• 2021

Background: This study aimed to determine the parameters for worsening oxygenation in non-severe coronavirus disease 2019 (COVID-19) pneumonia. Methods: This retrospective cohort study included cases of confirmed COVID-19 pneumonia in a public hospital in South Korea. The worsening oxygenation group was defined as that with SpO₂ ≤94% or received oxygen or mechanical ventilation (MV) throughout the clinical course versus the non-worsening oxygenation group that did not experience any respiratory event. Parameters were compared, and the extent of viral pneumonia from an initial chest computed tomography (CT) was calculated using artificial intelligence (AI) and measured visually by a radiologist. Results: We included 136 patients, with 32 (23.5%) patients in the worsening oxygenation group; of whom, two needed MV and one died. Initial vital signs and duration of symptoms showed no difference between the two groups; however, univariate logistic regression analysis revealed that a variety of parameters on admission were associated with an increased risk of a desaturation event. A subset of patients was studied to eliminate potential bias, that ferritin ≥280 ㎍/L (p=0.029), lactate dehydrogenase ≥240 U/L (p=0.029), pneumonia volume (p=0.021), and extent (p=0.030) by AI, and visual severity scores (p=0.042) were the predictive parameters for worsening oxygenation in a sex-, age-, and comorbid illness-matched case-control study using propensity score (n=52). Conclusion: Our study suggests that initial CT evaluated by AI or visual severity scoring as well as serum markers of inflammation on admission are significantly associated with worsening oxygenation in this COVID-19 pneumonia cohort.

• Journal of The Korean Society of Clinical Toxicology
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• v.10 no.2
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• pp.80-85
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• 2012

Purpose: The aim of this study was to describe the epidemiologic characteristics of adult patients with carbon monoxide poisoning who presented to the emergency department in recent years. Methods: This was a retrospective cohort study on adult consecutive patients with carbon monoxide (CO) poisoning who presented to the emergency department of a tertiary care university-affiliated hospital from January 1, 2008 to December 31, 2011. Results: A total of 91 patients were included in this study; there were 56(61.5%) unintentional and 35(38.5%) intentional poisonings. For the unintentional CO poisonings, the principal sources of exposure to CO were fire (39.3%), charcoal (17.9%), briquette charcoal (7.1%), wood burning boiler (7.1%), gas boiler (5.4%), automobile heater (3.6%), briquette boiler (3.6%), firewood (3.6%), and other items (12.5%). For the intentional CO poisonings, the sources were ignition charcoal (60.0%), briquette (31.4%), charcoal (5.7%) and butane gas (2.9%). For the unintentional CO poisonings, the places of poisoning were the home (58.9%), workplace (10.7%), public accommodation (8.9%), tent (8.9%), automobile (3.6%) and parking place (1.8%). For the intentional CO poisonings, the places of poisoning were the home (77.1%), public accommodation (11.4%) and automobile (11.4%). The proportion of intentional CO poisonings among total poisonings has increased significantly in recent years; 0.0% in 2008, 3.3% in 2009, 5.5% in 2010, and 29.7% in 2011. Conclusion: This study showed that in recent years in Korea, the source of CO has diversified broadly and intentional CO poisonings from burning ignition charcoal or briquettes has increased. Prevention efforts should consider these factors.

• Korean Journal of Radiology
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• v.24 no.2
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• pp.170-170
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• 2023

• Journal of Korean Medical classics
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• v.23 no.4
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• pp.63-102
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• 2010

Purpose : To propose various types of clinical research which is feasible for botanical new drug (IND) development processes, and suggest essential steps to development of study protocol for IND. Methods : Literature-based discussions and one research group's experience is given regarding domestic act, regulation, and system. Results : In order to get an approval of IND for botanical drug in Korea there are several types of clinical research to conduct. In quality control steps for standardized medicinal herbs, case reports or case series can be conducted, and for good manufacturing practice(GMP) steps, we can conduct case reports, case series, and retrospective cohort studies. In addition, as long as we gathered good laboratory practice(GLP) data we can conduct up to quasi-experimental studies and clinical trials including investigator initiated trials. In order to conduct these studies development of study protocol is essential. First, we obtain historical evidence including target disease and indication, efficacy, safety, and endpoints by reviewing medical classics. Second, we obtain clinically and statistically important data by conducting non-clinical studies, observation studies, and quasi-experimental studies. Third, we generate research hypotheses and purposes and explore methodologies, endpoints, clinical practice guidelines, cost-effectiveness, and commercial potential. Finally, we develop study protocol with aid of biostatistician or expert in contract research organization. Discussions and conclusions : This study have obvious limitations in that most thoughts, suggestions, and proposes are from one research group's experience. Therefore, we hope to see various types of research in this topic and process from other research group as well.