• 응용통계연구
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• 제35권4호
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• pp.485-499
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• 2022

표본오차와 비표본오차를 포함하는 총오차(total survey error)를 관리하는 것은 표본설계에서 매우 중요하다. 무응답으로 인해 발생한 비표본오차는 총오차에서 차지하는 비중이 매우 크며 이를 해결하는 방법인 무응답 대체에 관한 다수의 연구가 수행되었다. 최근 전통적 통계학 관련 기법에 추가하여 기계학습 관련 기법을 이용한 무응답 대체법이 다수 연구되고 실질적으로 사용되고 있다. 기존에 발표된 다수의 방법은 MCAR(missing completely at random) 또는 MAR(missing at random) 가정을 사용하고 있다. 그러나 관심변수에 영향을 받는 MNAR(missing not at random) 또는 무시할 수 없는 무응답(non-ignorable non-response; NN)은 편향을 발생시켜 대체 결과의 정확성을 크게 떨어뜨리지만 이에 관한 연구는 상대적으로 미미하다. 본 연구에서는 무시할 수 없는 무응답이 발생한 경우에 적용 가능한 무응답 대체법을 제안하였다. 특히 편향을 추정한 후 이를 제거하는 방법을 이용하여 무응답 대체 결과의 정확성을 향상하는 방법을 제안하였다. 또한, 모의실험을 이용하여 제안된 방법의 타당성을 확인하였다.

• Journal of Chest Surgery
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• 제55권1호
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• pp.30-36
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• 2022

Background: No consensus exists regarding whether volatile anesthetics are superior to intravenous anesthetics for reducing postoperative pulmonary complications (PPCs) in patients undergoing general anesthesia for surgery. Studies of this issue focused on anatomic pulmonary resection are lacking. This study compared the effects of total intravenous anesthesia (TIVA) versus volatile anesthesia on PPCs after anatomic pulmonary resection in patients with lung cancer. Methods: This retrospective study examined the medical records of patients with lung cancer who underwent lung resection at our center between January 2018 and October 2020. The primary outcome was the incidence of PPCs, which included prolonged air leak, pneumonia, acute respiratory distress syndrome, empyema, atelectasis requiring bronchofiberscopy (BFS), acute lung injury (ALI), bronchopleural fistula (BPF), pulmonary embolism, and pulmonary edema. Propensity score matching (PSM) was used to balance the 2 groups. In total, 579 anatomic pulmonary resection cases were included in the final analysis. Results: The analysis showed no statistically significant difference between the volatile anesthesia and TIVA groups in terms of PPCs, except for prolonged air leak. Neither of the groups showed atelectasis requiring BFS, ALI, BPF, pulmonary embolism, or pulmonary edema after PSM. However, the length of hospitalization, intensive care unit stay, and duration of chest tube indwelling were shorter in the TIVA group. Conclusion: Volatile anesthetics showed no superiority compared to TIVA in terms of PPCs after anatomical pulmonary resection in patients with lung cancer. Considering the advantages of each anesthetic modality, appropriate anesthetic modalities should be used in patients with different risk factors and situations.

• Journal of Chest Surgery
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• 제56권1호
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• pp.16-22
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• 2023

Background: Postoperative air leaks after pulmonary resection prolong the duration of chest drainage and the length of hospital stay. One of the many treatment options is bedside pleurodesis using various agents. This study evaluated the feasibility of an early intervention to stop postoperative air leaks with either autologous blood or a 50% glucose solution. Methods: We retrospectively reviewed 323 patients who underwent bedside pleurodesis between January 2017 and March 2022. Sixty-four patients received autologous blood patch pleurodesis, and 36 were treated with a 50% glucose solution after pulmonary resection. The primary endpoints were the total postoperative tube indwelling time, post-pleurodesis tube indwelling time, and hospital stay. A propensity score-matched analysis was performed. Results: In the autologous blood patch pleurodesis and 50% glucose solution groups, the mean initiation timing of postoperative pleurodesis were 2.06±1.62 and 3.28±1.56 days, the mean duration of the tube indwelling time after surgery was 6.58±3.02 and 6.42±4.92 days, and the mean duration of the tube indwelling time after pleurodesis, it was 4.53±3.10 and 3.11±4.80 days, respectively. In addition, the total length of hospital stay was 9.11±5.42 and 7.83±4.75 days in the autologous blood patch pleurodesis and 50% glucose solution groups, respectively. Conclusion: Early postoperative air leak cessation with autologous blood patch pleurodesis or 50% glucose solution pleurodesis is a feasible procedure with acceptable outcomes that effectively shortens the hospital stay.

• Journal of Acupuncture Research
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• 제40권3호
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• pp.252-264
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• 2023

Background: The primary aim of this study is to statistically analyze and compare the difference in treatment outcomes based on the frequency and duration of acupotomy treatment for lumbar disk herniation. Methods: The evaluation of efficacy and safety involved using visual analog scale (VAS), numeric rating scale (NRS), Roland Morris disability questionnaire (RMDQ), EuroQol 5-dimention (EQ-5D), and similar parameters. This was achieved through the establishment of a comparable cohort using propensity score matching. Group A comprised 46 patients who underwent 4 sessions of acupotomy treatment for 2 weeks, while Group B consisted of 15 patients who received 6 acupotomy sessions for 3 weeks. Results: For Group A, the average amount of change in VAS values at weeks 4 and 6 was significantly decreased. However, the average amount of change in RMDQ values was not significant. Notably, the average amount of change of EQ-5D values at week 6 increased significantly. As for Group B, the average amount of change of NRS values in weeks 2 and 3 was significantly decreased. Conversely, the average amount of change in RMDQ and EQ-5D values was not significant. In comparing the 2 groups at the final follow-up, the average amount of change in all evaluation values was not significant. Further, no significant interaction effect was observed in the changes over time in all evaluation values between the 2 groups. Conclusion: This study establishes that there was no statistically significant difference in pain reduction, functional impairment, and quality of life improvement between 2 group.

• 기술혁신연구
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• 제30권4호
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• pp.57-82
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• 2022

최근 중소기업 혁신 지원 전략이 시장 중심의 혁신을 유도하는 방향으로 전환되면서 중소기업이 수행하는 정부 R&D의 세부과제 지원 유형 중 자유공모형 과제의 비중이 높아지고 있다. 본 연구는 이처럼 증가하고 있는 자유공모형 과제의 특성과 효과성에 대해 이론적으로 살펴보고 실증분석을 통해 어떤 조건에서 자유공모형 과제가 될 가능성이 높아지는지, 성과 측면에서는 어떠한 차이점이 있는지 알아보았다. 먼저 시장수요 중심으로의 국가 R&D전략 전환과 수요견인 혁신 관점에서 세부과제 지원 유형 중 자유공모형 과제의 특성과 의미에 대해 살펴보고, 자원기반 관점으로 자유공모형 과제가 성과측면에서 유리할 수 있다는 것을 이해하였다. 그 후 로짓분석과 성향점수매칭법 등 실증분석을 통해 자유공모형 과제가 될 확률이 높아지는 과제 특성과 수행기업의 특성을 밝히고, 자유공모형 과제가 연구비 1억원 당 더 많은 혁신 성과를 나타낸다는 결과를 얻었다.

• Journal of Korean Neurosurgical Society
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• 제66권1호
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• pp.63-71
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• 2023

Objective : Traumatic brain injury (TBI) is one of the most common injuries in patients with multiple trauma, and it associates with high post-traumatic mortality and morbidity. A trauma center was established to provide optimal treatment for patients with severe trauma. This study aimed to compare the treatment outcomes of patients with severe TBI between non-trauma and trauma centers based on data from the Korean Neuro-Trauma Data Bank System (KNTDBS). Methods : From January 2018 to June 2021, 1122 patients were enrolled in the KNTDBS study. Among them, 253 patients from non-traumatic centers and 253 from trauma centers were matched using propensity score analysis. We evaluated baseline characteristics, the time required from injury to hospital arrival, surgery-related factors, neuromonitoring, and outcomes. Results : The time from injury to hospital arrival was shorter in the non-trauma centers (110.2 vs. 176.1 minutes, p=0.012). The operation time was shorter in the trauma centers (156.7 vs. 128.1 minutes, p=0.003). Neuromonitoring was performed in nine patients (3.6%) in the non-trauma centers and 67 patients (26.5%) in the trauma centers (p<0.001). Mortality rates were lower in trauma centers than in non-trauma centers (58.5% vs. 47.0%, p=0.014). The average Glasgow coma scale (GCS) at discharge was higher in the trauma centers (4.3 vs. 5.7, p=0.011). For the Glasgow outcome scale-extended (GOSE) at discharge, the favorable outcome (GOSE 5-8) was 17.4% in the non-trauma centers and 27.3% in the trauma centers (p=0.014). Conclusion : This study showed lower mortality rates, higher GCS scores at discharge, and higher rates of favorable outcomes in trauma centers than in non-trauma centers. The regional trauma medical system seems to have a positive impact in treating patients with severe TBI.

• 대한한의학회지
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• 제43권3호
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• pp.65-78
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• 2022

Objectives: The purpose of this study is to analyze the weight loss and the adverse events of overweight and obese adults on weight loss program with face-to-face treatment (FTF) and non-face-to-face treatment (NFTF) in 6 Korean Medicine obesity clinics. Methods: From March 2nd to March 10th, 2021, we collected data with a retrospective way from overweight and obese adults (body mass index, BMI≥23 kg/m²) who registered for a 12-week Gamitaeeumjowi-tang prescription program. After matching initial information of the FTF group and the NFTF group using propensity matching score, weight loss and BMI change were analyzed, and adverse events were evaluated in terms of causality, severity and system-organ classes. Results: Weight and BMI change from baseline to 12 weeks was -7.98±3.09kg (10.41±3.57%), -3.03±1.14kg/m² and -7.30±3.11kg (9.59±3.45%), -2.76±1.15kg/m² for FTF group and NFTF group, respectively. Body weight and BMI significantly decreased before and after treatment in both groups, and there was no significant difference in weight loss and BMI change between the two groups. No serious adverse events were reported. Conclusions: This study showed the potential that NFTF weight management treatment could be a good alternative way to FTF weight management treatment without serious adverse events.

• 한국임상약학회지
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• 제32권1호
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• pp.37-46
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• 2022

Background: Non-valvular atrial fibrillation (NVAF) is associated with ischemic stroke risk in the aging population. Observational studies have indicated beneficial effects of direct-acting oral anticoagulant (DOAC) against ischemic stroke compared to warfarin. This study aimed to investigate ischemic stroke incidence and bleeding risk in patients on DOAC therapy. Methods: Using the database of Korean Health Insurance Review and Assessment-Aged Patient Sample 2015, we conducted a retrospective cohort study. Study subjects with NVAF diagnosis and prescribed anticoagulants were enrolled. Propensity score (PS) matching by age, sex, comorbidities, and medications were used. The clinical outcomes were major adverse cerebro-cardiovascular events (MACCEs, ischemic stroke/systemic embolism, myocardial infarction, cardiac death) and bleeding events. A cox proportional hazard model analysis was performed to compare the outcomes with hazard ratio (HR) and 95% confidence interval (CI). Results: Total 4,773 elderly patients with NVAF were initially included. Four PS-matched groups including rivaroxaban vs. warfarin-only (n=1,079), dabigatran vs. warfarin-only (n=721), rivaroxaban vs. dabigatran (n=721), and switchers of warfarin to rivaroxaban vs. warfarin-only (n=287) were analyzed. Every group showed statistically similar results of MACCEs and bleeding events, except for the group of rivaroxaban vs. dabigatran. Rivaroxaban users showed higher risks of bleeding events than dabigatran users (HR 2.25, 95% CI 1.01-4.99). Conclusion: In the elderly patients with NVAF, efficacy and safety outcomes among oral anticoagulants including DOACs and warfarin were similar, while rivaroxaban are more likely to have higher bleeding risks than dabigatran. Further research using large size sample is needed.

• 대한예방한의학회지
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• 제28권1호
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• pp.69-87
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• 2024

Objectives : This study is to investigate the current National Health Insurance Database cohort studies related to complications of Parkinson's Disease (PD) and suggest the design of Korean medical epidemiological studies of PD. Methods : Nationwide longitudinal studies of PD patients in South Korea were collected through Pubmed and the Korea Citation Index (KCI). We selected cohort studies that used the National Health Insurance Database in Korea and targeted Parkinson's disease patients. Studies published before February 2024 were categorized according to study designs. We examined variables and covariates, enroll dates and matching methods. Results : Of a total of 536 studies, 18 studies met the inclusion criteria. All studies used the National Health Insurance (NHI) Research Database and among them, 5 used sample data and one senior database. Studies can be classified into two types. 11 cohort studies were comparing PD patients and non-PD patients. Another type was 4 PD patients cohort studies. Most studies used two diagnostic codes (G20 and V124) for inclusion criteria. Enroll periods were from 2002 to 2017, and follow-up periods were from 7 to 14 years. 16 studies considered age and sex as covariates. 15 studies used the propensity score matching method to increase the level of causality. There was only one study related to the Korean medical treatment. Conclusion : In future cohort studies on Korean medical treatment, more attempts should be made to reveal the effect of the treatments on PD patients by defining inclusion criteria for patient groups, covariates, exposure variables, and assessment indicators more operatively.

• Journal of Chest Surgery
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• 제57권2호
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• pp.178-183
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• 2024

Background: The superficial veins are commonly used in conventional autogenous arteriovenous fistulas and the placement of prosthetic grafts. When they are unsuitable, however, the use of the deep veins (venae comitantes) is generally considered to be a reasonable alternative. This study conducted a comparative analysis of clinical outcomes for arteriovenous grafts between 2 groups based on the type of venous outflow: superficial veins or venae comitantes. Methods: In total, 151 patients who underwent arteriovenous grafts from November 2005 to March 2022 were retrospectively analyzed. The patients were divided into 2 groups: group A (superficial veins, n=89) and group B (venae comitantes, n=62). The primary, secondary patency, and complication rates were analyzed in each group. A propensity score-matched analysis was performed. Results: In total, 55 well-balanced pairs were matched. Kaplan-Meier analysis revealed no significant differences in the primary patency rate between the 2 groups at 1-year, 3-year and 5-year intervals (group A, 54.7%, 35.9%, 25.4% vs. group B, 47.9%, 16.8%, 12.6%; p=0.14), but there was a difference in the secondary patency rate (group A, 98.2%, 95.3%, 86.5% vs. group B, 87.3%, 76.8%, 67.6%; p=0.0095). The rates of complications, simple percutaneous transluminal angioplasty, and stent insertion were comparable between the groups. Conclusion: Although this study demonstrated not particularly favorable secondary patency rates in the venae comitantes group, the venae comitantes may still be a viable option for patients with unsuitable superficial veins because there were no significant differences in the primary patency and complication rates between the 2 groups.