• Title/Summary/Keyword: Retrospective Statistical Analysis

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Evaluation of bias and uncertainty in snow depth reanalysis data over South Korea (한반도 적설심 재분석자료의 오차 및 불확실성 평가)

  • Jeon, Hyunho;Lee, Seulchan;Lee, Yangwon;Kim, Jinsoo;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.56 no.9
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    • pp.543-551
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    • 2023
  • Snow is an essential climate factor that affects the climate system and surface energy balance, and it also has a crucial role in water balance by providing solid water stored during the winter for spring runoff and groundwater recharge. In this study, statistical analysis of Local Data Assimilation and Prediction System (LDAPS), Modern.-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), and ERA5-Land snow depth data were used to evaluate the applicability in South Korea. The statistical analysis between the Automated Synoptic Observing System (ASOS) ground observation data provided by the Korea Meteorological Administration (KMA) and the reanalysis data showed that LDAPS and ERA5-Land were highly correlated with a correlation coefficient of more than 0.69, but LDAPS showed a large error with an RMSE of 0.79 m. In the case of MERRA-2, the correlation coefficient was lower at 0.17 because the constant value was estimated continuously for some periods, which did not adequately simulate the increase and decrease trend between data. The statistical analysis of LDAPS and ASOS showed high and low performance in the nearby Gangwon Province, where the average snowfall is relatively high, and in the southern region, where the average snowfall is low, respectively. Finally, the error variance between the four independent snow depth data used in this study was calculated through triple collocation (TC), and a merged snow depth data was produced through weighting factors. The reanalyzed data showed the highest error variance in the order of LDAPS, MERRA-2, and ERA5-Land, and LDAPS was given a lower weighting factor due to its higher error variance. In addition, the spatial distribution of ERA5-Land snow depth data showed less variability, so the TC-merged snow depth data showed a similar spatial distribution to MERRA-2, which has a low spatial resolution. Considering the correlation, error, and uncertainty of the data, the ERA5-Land data is suitable for snow-related analysis in South Korea. In addition, it is expected that LDAPS data, which is highly correlated with other data but tends to be overestimated, can be actively utilized for high-resolution representation of regional and climatic diversity if appropriate corrections are performed.

Analysis of prognostic factors through survival rate analysis of oral squamous cell carcinoma patients treated at the National Cancer Center: 20 years of experience

  • Choi, Yong-Seok;Kim, Min Gyeong;Lee, Jong-Ho;Park, Joo-Yong;Choi, Sung-Weon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.48 no.5
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    • pp.284-291
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    • 2022
  • Objectives: This study aimed to analyze the clinicopathological prognostic factors affecting the survival of patients with oral squamous cell carcinoma (OSCC). Materials and Methods: A retrospective study was conducted on patients with OSCC who received treatment at the Oral Oncology Clinic of the National Cancer Center (NCC) from June 2001 to December 2020. The patients' sex, age, primary site, T stage, node metastasis, TNM staging, perineural invasion (PNI), lymphovascular invasion (LVI), differentiation, surgical resection margin, smoking, and drinking habits were investigated to analyze risk factors. For the univariate analysis, a Kaplan-Meier survival analysis and log-rank test were used. Additionally, for the multivariable analysis, a Cox proportional hazard model analysis was used. For both analyses, statistical significance was considered when P<0.05. Results: During the investigation period, 407 patients were received surgical treatment at the NCC. Their overall survival rate (OS) for five years was 70.7%, and the disease-free survival rate (DFS) was 60.6%. The multivariable analysis revealed that node metastasis, PNI, and differentiation were significantly associated with poor OS. For DFS, PNI and differentiation were associated with poor survival rates. Conclusion: In patients with OSCC, cervical node metastasis, PNI, and differentiation should be considered important prognostic factors for postoperative survival.

A Retrospective Statistical Analysis of Miniscalpel Needle Therapy for Herniated Intervertebral Disc or Spinal Stenosis

  • Kim, Jae Ik;Jeong, Jeong Kyo;Kim, Myung Kwan;Jeon, Ju Hyun;Kim, Eun Seok;Kim, Young Il
    • Journal of Acupuncture Research
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    • v.35 no.4
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    • pp.226-237
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    • 2018
  • Background: This study examined the characteristics and prognosis of patients admitted to the Dunsan Korean medicine hospital for treatment of herniated intervertebral disc (HIVD) or spinal stenosis with Miniscalpel needle therapy (MSN). Methods: Patients were admitted to the Dunsan Korean medicine hospital from January 01, 2016 to September 30, 2017 for the treatment of HIVD or spinal stenosis with MSN. Crossover analysis, Independent sample t test, one-way ANOVA, multiple linear regression analysis, and binary logistic regression analysis were performed. Results: Crossover analysis showed statistically significant differences in treatment methods according to gender, current pain according to the disease duration, satisfaction of MSN according to disease duration, treatment methods, and intention of re-treatment with MSN according to treatment methods. Independent t test and one-way ANOVA showed that there was a difference in current Numeric Rating Scale (NRS) according to disease duration, and difference between discharge and current NRS, and number of MSN according to disease. Multiple linear regression analysis showed that age, disease duration, and number of MSN affect discharge NRS, disease duration, and number of MSN affect current NRS, and Western medical treatment after MSN, discharge NRS, and current NRS affect satisfaction of MSN. Binary logistic regression analysis showed that discharge NRS affects current pain, and gender, discharge NRS, and treatment methods affect intention of re-treatment with MSN. Conclusion: Characteristics, prognosis, satisfaction and variables affecting prognosis of MSN were statistically significant, indicating that more systematic studies are required to further examine the effects of MSN on HIVD or spinal stenosis.

Comparison of marginal bone loss between internal- and external-connection dental implants in posterior areas without periodontal or peri-implant disease

  • Kim, Dae-Hyun;Kim, Hyun Ju;Kim, Sungtae;Koo, Ki-Tae;Kim, Tae-Il;Seol, Yang-Jo;Lee, Yong-Moo;Ku, Young;Rhyu, In-Chul
    • Journal of Periodontal and Implant Science
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    • v.48 no.2
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    • pp.103-113
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    • 2018
  • Purpose: The purpose of this retrospective study with 4-12 years of follow-up was to compare the marginal bone loss (MBL) between external-connection (EC) and internal-connection (IC) dental implants in posterior areas without periodontal or peri-implant disease on the adjacent teeth or implants. Additional factors influencing MBL were also evaluated. Methods: This retrospective study was performed using dental records and radiographic data obtained from patients who had undergone dental implant treatment in the posterior area from March 2006 to March 2007. All the implants that were included had follow-up periods of more than 4 years after loading and satisfied the implant success criteria, without any peri-implant or periodontal disease on the adjacent implants or teeth. They were divided into 2 groups: EC and IC. Subgroup comparisons were conducted according to splinting and the use of cement in the restorations. A statistical analysis was performed using the Mann-Whitney U test for comparisons between 2 groups and the Kruskal-Wallis test for comparisons among more than 2 groups. Results: A total of 355 implants in 170 patients (206 EC and 149 IC) fulfilled the inclusion criteria and were analyzed in this study. The mean MBL was 0.47 mm and 0.15 mm in the EC and IC implants, respectively, which was a statistically significant difference (P<0.001). Comparisons according to splinting (MBL of single implants: 0.34 mm, MBL of splinted implants: 0.31 mm, P=0.676) and cement use (MBL of cemented implants: 0.27 mm, MBL of non-cemented implants: 0.35 mm, P=0.178) showed no statistically significant differences in MBL, regardless of the implant connection type. Conclusions: IC implants showed a more favorable bone response regarding MBL in posterior areas without peri-implantitis or periodontal disease.

Fracture patterns in the maxillofacial region: a four-year retrospective study

  • Park, Kyung-Pil;Lim, Seong-Un;Kim, Jeong-Hwan;Chun, Won-Bae;Shin, Dong-Whan;Kim, Jun-Young;Lee, Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.41 no.6
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    • pp.306-316
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    • 2015
  • Objectives: The facial bones are the most noticeable area in the human body, and facial injuries can cause significant functional, aesthetic, and psychological complications. Continuous study of the patterns of facial bone fractures and changes in trends is helpful in the prevention and treatment of maxillofacial fractures. The purpose of the current clinico-statistical study is to investigate the pattern of facial fractures over a 4-year period. Materials and Methods: A retrospective analysis of 1,824 fracture sites was carried out in 1,284 patients admitted to SMG-SNU Boramae Medical Center for facial bone fracture from January 2010 to December 2013. We evaluated the distributions of age/gender/season, fracture site, cause of injury, duration from injury to treatment, hospitalization period, and postoperative complications. Results: The ratio of men to women was 3.2:1. Most fractures occurred in individuals aged between teens to 40s and were most prevalent at the middle and end of the month. Fractures occurred in the nasal bone (65.0%), orbital wall (29.2%), maxillary wall (15.3%), zygomatic arch (13.2%), zygomaticomaxillary complex (9.8%), mandibular symphysis (6.5%), mandibular angle (5.9%), mandibular condyle (4.9%), and mandibular body (1.9%). The most common etiologies were fall (32.5%) and assault (26.0%). The average duration of injury to treatment was 6 days, and the average hospitalization period was 5 days. Eighteen postoperative complications were observed in 17 patients, mainly infection and malocclusion in the mandible. Conclusion: This study reflects the tendency for trauma in the Seoul metropolitan region because it analyzes all facial fracture patients who visited our hospital regardless of the specific department. Distinctively, in this study, midfacial fractures had a much higher incidence than mandible fractures.

The Effectiveness of Ultrasound-Guided Soyeom Pharmacopuncture Therapy at Acromioclavicular Joint of Shoulder in Patients with Anterior Shoulder Pain: A Retrospective Study (견관절 전방 통증 환자에서 초음파 유도하 견쇄관절 소염약침요법 병행 치료의 효과: 후향적 연구)

  • Kim, Sang Woo;Jeon, Dong-Hwi;Kim, Byung-Jun;Park, Jeong-Wook;Oh, Min-Seok
    • Journal of Korean Medicine Rehabilitation
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    • v.31 no.3
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    • pp.95-104
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    • 2021
  • Objectives The purpose of this study was to observe effectiveness of ultrasound-guided Soyeom pharmacopuncture therapy at acromioclavicular joint of shoulder in patients with anterior shoulder pain. Methods We analyzed medical records of 9 patients hospitalized with anterior shoulder pain who had admitted to Department of Korean Rehabilitation Medicine, College of Korean Medicine, Daejeon University from March 1, 2021 to June 13, 2021. 9 patients were treated the treatment of Soyeom pharmacopuncture therapy on acromioclavicular joint under ultrasonic guidance with Korean medicine treatment (such as herbal medicine, acupuncture, moxabustion, etc). The study was conducted as a retrospective observation study which analyze the patient's medical records. We used numeric rating scale (NRS) to evaluate pain reduction and the shoulder range of motion (ROM) to evaluate function improvement twice (before pharmacopuncture treatment and 5 days later treatment). Statistical analysis was performed using the IBM SPSS Statistics version 25 program (IBM Co., Armonk, NY, USA). Results The average of numeric rating scale reduced statistically significantly from 5.56±1.13 to 3.11±1.36 (p=0.004). The average of shoulder flexion ROM increased statistically significantly from 166.67±8.17° to 175.00±8.37° (p<0.05). And the average of shoulder abduction ROM increased statistically significantly from 158.57±20.35° to 172.86±12.53° (p<0.05). Both NRS and shouler ROM showed statistically significantly improve after treatment. Conclusions This study shows ultrasound-guided Soyeom pharmacopuncture therapy at acromioclavicular joint of shoulder has a meaningful clinical effect on the improving shoulder pain and ROM especially on flexion and abduction.

Comparative esthetic evaluation of anterior zone with immediate, early, and delay implantation (전치부 영역 임플란트의 식립 시기에 따른 심미적 평가)

  • Kim, Jung-Hwa;Seo, Seong-Yong;Kim, Na-Hong;Yu, Jung-Hyun;Lee, Dong -Woon
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.26 no.1
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    • pp.17-23
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    • 2017
  • Purpose: This retrospective study is to evaluate whether the timing of implant placement and the result of esthetic outcomes are related. Materials and Methods: Among the patients who had undergone single implant surgery on anterior area from 2010 to 2013 in Veterans Health Service Medical Center, 34 implants in 27 patients (24 male and 3 female) were selected and categorized into 3 groups according to the timing of placement, which are group D (Delay), group E (Early) and group I (Immediate). Aesthetic indices used included the Pink Esthetic Score (PES). It has 7 variables scores, such as mesial papilla, distal papilla, a level of soft-tissue margin, soft-tissue contour, alveolar process, soft-tissue color, and soft-tissue texture. Each variable ranges from 0 to 2, therefore total 14 points are highest. All patients were received by regular follow-up at least 1-year. One examiner measured PES on the intraoral photos. Each patient was considered as a statistical unit for statistical analysis. Statistical analyses were performed using a commercially available statistical software (SPSS Statistics 21.0, IBM Corp., Armonk, NY, USA). Kruskal-Wallis test was used for inter-group comparisons. Statistical significance was set at P<0.05. Result: Mean score in Group D, Group I, and Group E were $11.5{\pm}1.5$, $11.4{\pm}1.8$, and $11.3{\pm}1.8$ respectively. In Kruskal-Wallis test, there are no differences (P=0.989). Conclusion: In this limited study suggests that clinical aesthetic results can be achieved with all treatment protocols. Finally, various factors can be considered to produce the esthetic results.

Factors Associating Major Burn in Chemical Injury Patients due to Industrial Place Incident : A Retrospective study (산업장 화학 손상 환자에서 중증 화상에 영향을 미치는 요인)

  • Shin, Hee-Jun;Oh, Se-Kwang;Lee, Han-You
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.332-339
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    • 2016
  • This study examined the intensity of the association of factors affecting major burns by statistical analysis for patients injured by the release of chemical hazards. A total of 446 patients were evaluated as chemical injury patients, who had visited the emergency room from 1/Jan/2010 to 31/Dec/2014. The major burn was used as a dependent variable representing the severity of chemical injury. A chi-square test (CST) and binary logistic regression test (BLRA) were used as the statistical analysis method for determining the association between major burns and the independent variables. In CST, female and their presence at an incident scene, multiple site injury were associated with major burn (p<0.05). In BLRA, the presence at an incident scene and spills (comparing explosion), discharge (comparing admission) were associated with major burns (p<0.05). In this study, the presence at an incident scene was the most significant factor concerning major burns. Furthermore, gender and injury number, exposure mechanism (spill comparing explosion), and disposition (discharge comparing admission) were also associated with major burns.

Predictive Bayesian Network Model Using Electronic Patient Records for Prevention of Hospital-Acquired Pressure Ulcers (전자의무기록을 이용한 욕창발생 예측 베이지안 네트워크 모델 개발)

  • Cho, In-Sook;Chung, Eun-Ja
    • Journal of Korean Academy of Nursing
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    • v.41 no.3
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    • pp.423-431
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    • 2011
  • Purpose: The study was designed to determine the discriminating ability of a Bayesian network (BN) for predicting risk for pressure ulcers. Methods: Analysis was done using a retrospective cohort, nursing records representing 21,114 hospital days, 3,348 patients at risk for ulcers, admitted to the intensive care unit of a tertiary teaching hospital between January 2004 and January 2007. A BN model and two logistic regression (LR) versions, model-I and .II, were compared, varying the nature, number and quality of input variables. Classification competence and case coverage of the models were tested and compared using a threefold cross validation method. Results: Average incidence of ulcers was 6.12%. Of the two LR models, model-I demonstrated better indexes of statistical model fits. The BN model had a sensitivity of 81.95%, specificity of 75.63%, positive and negative predictive values of 35.62% and 96.22% respectively. The area under the receiver operating characteristic (AUROC) was 85.01% implying moderate to good overall performance, which was similar to LR model-I. However, regarding case coverage, the BN model was 100% compared to 15.88% of LR. Conclusion: Discriminating ability of the BN model was found to be acceptable and case coverage proved to be excellent for clinical use.

Posttransplant Malignancies in Renal Transplant Recipients: 22-years Experience from a Single Center in Pakistan

  • Yunus, Mahira;Aziz, Tahir;Mubarak, Muhammed
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.2
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    • pp.575-578
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    • 2012
  • Objective: To study the incidence, types and distribution pattern of malignant tumors in renal transplant recipients at a single center in Pakistan. Materials and methods: This retrospective study was conducted at Sindh Institute of Urology and Transplantation (SIUT) and included all transplant patients on regular follow-up from November 1986 to December 2008. The original biopsy reports and case files of all patients who developed posttransplant malignancies were reviewed and relevant demographic, clinical, radiological, and histopathological data were retrieved and analyzed. SPSS version 10.0 was used for statistical analysis. Results: Over 22 years of study period, 1816 renal transplants were carried out at our center. Among these, 44 patients developed malignancies constituting an overall incidence rate of 2.4%. All patients in this study were males with a mean age of $34.9{\pm}9.5$ years (range: 9 to 60 years). The most common type of malignancy was lymphoma (27 patients, 61.4%), followed by Kaposi's sarcoma (11 patients, 25%) and skin malignancies (3 patients, 6.8%). One case each of adenocarcinoma of the gallbladder, acute myeloid leukemia (AML), conjunctival carcinoma-in-situ and seminoma were also diagnosed. Conclusion: Posttransplant malignancies occurring in our renal transplant recipients show different incidence rates and patterns as compared with western studies.