• The Korean Journal of Applied Statistics
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• v.35 no.4
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• pp.485-499
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• 2022

Controlling the total survey error including sampling error and non-sampling error is very important in sampling design. Non-sampling error caused by non-response accounts for a large proportion of the total survey error. Many studies have been conducted to handle non-response properly. Recently, a lot of non-response imputation methods using machine learning technique and traditional statistical methods have been studied and practically used. Most imputation methods assume MCAR(missing completely at random) or MAR(missing at random) and few studies have been conducted focusing on MNAR (missing not at random) or NN(non-ignorable non-response) which cause bias and reduce the accuracy of imputation. In this study, we propose a non-response imputation method that can be applied to non-ignorable non-response. That is, we propose an imputation method to improve the accuracy of estimation by removing the bias caused by NN. In addition, the superiority of the proposed method is confirmed through small simulation studies.

• Journal of Chest Surgery
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• v.55 no.1
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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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• v.56 no.1
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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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• v.40 no.3
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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.

• Journal of Technology Innovation
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• v.30 no.4
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• pp.57-82
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• 2022

As the strategy to support SMEs' innovation has shifted to induce market-oriented innovation, the Korean government increasingly invests in grant-type R&D projects proposed by SME firms. This study reveals the characteristics of grant-type R&D projects proposed by SME firms through a transition of national R&D strategy and demand-pull innovation perspectives. This study also examines the differences between grant-type R&D projects proposed by firms and R&D projects led by the government through logit-analysis and propensity score matching methods. As a result, we found that a national R&D project for SMEs yields better innovation performance when the project is proposed by a company than led by the government.

• Journal of Korean Neurosurgical Society
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• v.66 no.1
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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.

• The Journal of Korean Medicine
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• v.43 no.3
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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.

• Korean Journal of Clinical Pharmacy
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• v.32 no.1
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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.

• Journal of Yeungnam Medical Science
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• v.40 no.4
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• pp.402-411
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• 2023

Background: We hypothesized that fatty liver disease (FLD) is associated with a high prevalence of hearing loss (HL) owing to metabolic disturbances. This study aimed to evaluate the association between FLD and HL in a large sample of the Korean population. Methods: We used a dataset of adults who underwent routine voluntary health checkups (n=21,316). Fatty liver index (FLI) was calculated using Bedogni's equation. The patients were divided into two groups: the non-FLD (NFLD) group (n=18,518, FLI <60) and the FLD group (n=2,798, FLI ≥60). Hearing thresholds were measured using an automatic audiometer. The average hearing threshold (AHT) was calculated as the pure-tone average at four frequencies (0.5, 1, 2, and 3 kHz). HL was defined as an AHT of >40 dB. Results: HL was observed in 1,370 (7.4%) and 238 patients (8.5%) in the NFLD and FLD groups, respectively (p=0.041). Compared with the NFLD group, the odds ratio for HL in the FLD group was 1.16 (p=0.040) and 1.46 (p<0.001) in univariate and multivariate logistic regression analyses, respectively. Linear regression analyses revealed that FLI was positively associated with AHT in both univariate and multivariate analyses. Analyses using a propensity score-matched cohort showed trends similar to those using the total cohort. Conclusion: FLD and FLI were associated with poor hearing thresholds and HL. Therefore, active monitoring of hearing impairment in patients with FLD may be helpful for early diagnosis and treatment of HL in the general population.

• Journal of Gastric Cancer
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• v.24 no.2
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• pp.210-219
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• 2024

Purpose: The study aimed to investigate real-world surgical outcomes of minimally invasive surgery (MIS) for advanced gastric cancer using Korean Gastric Cancer Association (KGCA)-led nationwide data. Materials and Methods: A nationwide survey of patients who underwent surgical treatment for gastric cancer in 2019 was conducted by the KGCA. A total of 14,076 patients from 68 institutions underwent surgery, and 4,953 patients diagnosed with pathological stages IB-III gastric cancer were included. Among them, 1,689 patients who underwent MIS (MIS group) and 1,689 who underwent the open approach (open group) were matched using propensity score in a 1:1 ratio. Surgical outcomes were compared, and multivariate analysis was performed to identify the independent factors for overall morbidity. Results: The MIS group had a lower proportion of D2 lymphadenectomy, total omentectomy, and combined resection. However, the number of harvested lymph nodes was higher in the MIS group. Better surgical outcomes, including less blood loss and shorter hospital stay, were observed in the MIS group, and the overall morbidity rate was significantly lower in the MIS group (17.5% vs. 21.9%, P=0.001). The mortality rates did not differ significantly between the 2 groups. In the multivariate analysis, the minimally invasive approach was a significant protective factor against overall morbidity (odds ratio, 0.799; P=0.006). Conclusions: Based on the Korean nationwide data, MIS for stage IB-III gastric cancer had better short-term outcomes than the open approach, including lower rates of wound complications, intra-abdominal abscesses, and cardiac problems.