• Journal of Chest Surgery
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• v.31 no.10
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• pp.931-938
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• 1998

Background: Anatomic correction of transposition of the great arteries by means of the arterial switch operation is now accepted as the therapeutic method of choice. This retrospective study attempts to assess the results of the neonatal arterial switch operation for transposition of the great arteries performed by our newly established institution. Materials and methods: 33 consecutive neonates underwent the arterial switch operation between October 1991 to November 1997. There were 27 neonates with transposition and intact ventricular septum, 3 with ventricular septal defect, and 3 with Taussig-Bing anomaly. The mean age was 10.9$\pm$7.9 days and mean body weight was 3.29$\pm$0.44kg. Results: Overall postoperative hospital mortality was 30.3% (10 patients). The mortality has improved with time; 75% (6 patients) among first 8 consecutive patients before 1994, 20% (2 patients) among 10 patients in 1994 and 1995, and 13.3% (2 patients) among 15 patients since 1996. Univariated analysis of risk factors revealed that earlier date of the operations and one of preoperative events were determinants for operative death. There were two late deaths. A mean follow-up of 17.4$\pm$16.5 months was achieved in all 21 survivors. All were in New York Heart Association functional class I. One patient had mild pulmonary stenosis and two had mild aortic valve regurgitation on their echocardiography. Conclusions: We concluded that we should continue to perform arterial switch operation for neonates with transposition of the great arteries because the mortality of the operation has been improved and the operative survivors have good functional results with low incidence of late complications.

• The Journal of the Korean life insurance medical association
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• v.22
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• pp.55-98
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• 2003

본 연구는 질병별사망율연구(疾病別死亡率硏究)의 이론적 기초를 제시하고 일본 선진보험사의 질병별사망율연구(疾病別死亡率硏究)의 경험을 고찰하고 국내 보험사들의 질병사망율연관데이터의 현황분석을 통해 향후 질병별사망율연구(疾病別死亡率硏究)의 결과를 얻기 위해 현재 보험사들이 전사적으로 준비하여야 할 것에 대해 제언을 하고자 한다. 사망률연구(mortality study)란 인구통계학적 개념을 기본으로 하여 역학적 연구방법의 하나인 코호트방법과 생존분석방법을 결합하여 인구집단(또는 피보험자 집단)을 대상으로 대량의 자료를 장기적으로 관찰하여 그 사망의 빈도와 분포를 기술하고 사망연관지수들을 알아내어 생명보험사업에 있어서 위험선택기술을 향상시키는 것이다. 초과사망을 및 사망비 산출의 실제를 생명표 방법론과 급성심근 경색증 환자의 생존 분석을 통해 알아본다. 생명표 방법론을 이용한 생존 분석방법이란 의학저널에서 발표된 논문을 사망률표로 변경하기 위한 필수적인 단계에 대한 것이다 관찰된 생존 곡선을 생명표 작성법의 한 방법인 비교 경험 사망률로 바꾸는데 초점을 두었다. 일본생명(日本生命)의 경우, 일본 협영생명(協塋生命)의 경우, 일본사망율조사(MA)위원회 생명보험사망을 연구고서등을 통해 질병별사망율연구(疾病別死亡率硏究)를 살펴 보았다. 일본은 질병별사망율(疾病別死亡率)을 구하기 위해서 1950년대 이후부터 체계적으로 자료를 모으고 축적, 분석하여 지속성을 유지하였다. 또한 일본MA위원회의 경우처럼 보험의학의사, 계리, 통계, 전산부서로 구성된 전담위원회의 통일된 협조가 질병별사망율연구(疾病別死亡率硏究)를 가능하게 하였다. 그리고 의학적인 관점에서 볼 때 일본보험의학계는 일본만의 독특한 질병분류로 분석하여 온 것이 특이하다. 질병별사망율연구(疾病別死亡率硏究)에 대해서는 모두가 필요성을 인정하면서도 구체적인 대비책은 없는 것이 우리나라 보험업계의 실정이다. 이러한 현실의 직접적인 이유는 질병별사망율연구(疾病別死亡率硏究)라는 것이 그 특성상 중장기적인 계획이며 많은 전문인력의 통합되고 집중된 노력이 요구되기 때문이다. 우리도 "생명보험사사망율연구위원회(Life Insurance Mortality Committee" (가칭)를 설치하고 장기적인 계획안을 먼저 만드는 것이 선행되어야 할 것이다. 지금부터 질병별사망율(疾病別死亡率) 데이터를 축적하고 매 5년 또는 매 10년마다 데이터를 분석한다면 질병별사망율(疾病別死亡率)에 대해 고유의 기술을 습득하는 것이 그리 먼 미래의 일만은 아닐 것이다.

• The Korean Journal of Applied Statistics
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• v.28 no.4
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• pp.703-719
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• 2015

We propose an extension of the Lee and Jho (2015) mean reverting the two factor mortality model by incorporating a period-specific cohort effect. We found that the consideration of cohort effect improves the mortality fit of Korea male data above age 65. Parameters are estimated by the weighted least squares method and Metropolis algorithm. We also emphasize that the cohort effect is necessary to choose the base survival index to calculate longevity bond issue price. A key contribution of the article is the proposal and development of a method to calculate the longevity bond price to hedge the longevity risk exposed to Korea National Pension Services.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.11a
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• pp.130-133
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• 2005

황사는 대기오염과 관련하여 심혈관계 및 호흡기계 질환으로 인한 사망 의 증가 등의 건강 영향으로 인해 관심의 대상이 되어왔다. 그러나 최근의 황사성분을 분석한 연구결과에 따르면 실제로 황사기간 동안에 전체먼지농도 중 조대먼지농도의 비율은 증가한 반면 미세먼지농도의 비율은 감소하였고 유해한 중금속의 농도도 별다른 변화를 보이지 않거나 오히려 감소하였다. 이에 본 연구에서는 서울시의 2000년부터 2002년, 2월부터 5월까지의 황사시기를 포함한 경우와 포함하지 않은 경우를 비교하여 황사현상으로 인한 대기먼지가 총사망에 미치는 영향을 비교하였다. 분석결과에 따르면 총사망에 미치는 대기먼지의 영향은, 황사시기를 포함하여 분석한 경우보다 황사시기를 제외하고 분석한 경우에서 더 큰 건강영향을 보였다. 즉, 황사시기를 제외하고 분석한 경우에서 대기먼지가 총사망에 미치는 위험의 크기가 더 큰 것으로 나타났다. 이는 황사의 화학성분 및 황사시 사람들의 행동양식의 변화와 같은 노출의 감소로 설명될 수 있으며 이는 도시 대기오염의 건강위해성을 평가함에 있어서 황사시기를 포함하여 분석하는 경우 도시 대기오염, 특히 대기먼지의 위해도를 과소평가할 가능성이 있으며, 지금까지 제안되는 기존의 연구결과보다 실제 도시 미세먼지의 건강영향이 훨씬 더 클 수 있음을 본 연구결과가 제시하고 있다.

• Neonatal Medicine
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• v.18 no.2
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• pp.221-227
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• 2011

Purpose: The objectives were to identify the characteristics of neonates with hydrops fetalis, and to identify the risk factors associated with mortality. Methods: A retrospective review of AMC (Asan Medical Center) dataset was performed from January 1990 to June 2009. The characteristics of 71 patients with hydrops fetalis were investigated and they were divided into two groups: the survived group and the expired group. Various perinatal and neonatal factors in two groups were compared to find out risk factors associated with mortality based on univariate analysis, followed by multiple regression analyses (SPSS version 18.0). Results: Of those 71 neonates (average gestational age: 33 weeks, birth weight: 2.6 kg), 38 survived, 33 died, resulting in overall mortality rate of 46.5%. The most common etiology was idiopathic followed by chylothorax, cardiac anomalies, twin-to-twin transfusion, meconium peritonitis, cardiac arrythmias, and congenital infections. Factors that were associated independently with mortality in logistic regression analyses were low 5-minutes Apgar score, hyaline membrane disease and delayed in achieving 50th percentile ideal body weight for appropriate gestational age by 10 days. Conclusion: In this study, 5-minutes Apgar score, hyaline membrane disease and delayed in achieving 50th percentile ideal body weight for appropriate gestational age by 10 days were significant risk factors associated with mortality in hydrops fetalis. Therefore, the risk of death among neonates with hydrops fetalis depends on the illness immediately after birth and severity of hydrops fetalis. Informations from this study may prove useful in prediction of prognosis to neonates with hydrops fetalis.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.535-541
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• 2002

Background: The prevalence of pulmonary tuberculosis remains high in several areas of the world, and pneumonectomy is often necessary to treat the sequelae of the disease. We retrospectively analyzed the morbidities, mortalities, and long-term outcomes after pneumonectomy for the treatment of tuberculous sequelae. Material and Method: Between 1981 and 2001, 94 patients underwent either pneumonectomy or extrapleural pneumonectomy for the treatment of tuberculous sequelae. There were 44 males and 50 females. The mean age was 40(16~68) years. The pathology included destroyed lung in 80, main bronchus stenosis in 10, and both lesions in 4. Surgical procedures were pneumonectomy in 47, extrapleural pneumonectomy in 43, and completion pneumonectomy in 4. Results: One patient died postoperatively due to empyema. Twenty-three complications occurred in 20 patients; empyema in 15(including 7 bronchopleural fistulas), wound infection in 5, and others in 3. Univariate analysis revealed presence of empyema, extrapleural pneumonectomy, prolonged operation time, and old age as risk factors of postpneumonectomy empyema. In multivariate analysis, old age and low preoperative FEV1 were risk factors of empyema. Low preoperative FEV1 was the risk factor of bronchopleural fistula(BPF) in univariate analysis. Low preoperative FEV1, positive sputum AFB, and presence of aspergilloma were risk factors of BPF in multivariate analysis. There were twelve late deaths. Actuarial 5-and 10-year survival rates were 94$\pm$3% and 87$\pm$4%, respectively. Conclusion: Pneumonectomy could be performed with acceptable mortality and morbidity, and could achieve good long-term survival for the treatment of tuberculous sequelae. In patients with risk factors, special care is recommended to prevent postoperative empyema or bronchopleural fistula.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.4
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• pp.327-339
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• 2022

The purpose of this study is to present the effective smoke control flow rate and mode for securing safety through quantitative risk assessment according to the smoke control flow rate and mode (supply or exhaust) of the platform when a train fire occurs at the subway platform. To this end, a fire outbreak scenario was created using a side platform with a central staircase as a model and fire analysis was performed for each scenario to compare and analyze fire propagation characteristics and ASET, evacuation analysis was performed to predict the number of deaths. In addition, a fire accident rate (F)/number of deaths (N) diagram (F/N diagram) was prepared for each scenario to compare and evaluate the risk according to the smoke control flow rate and mode. In the ASET analysis of harmful factors, carbon monoxide, temperature, and visible distance determined by performance-oriented design methods and standards for firefighting facilities, the effect of visible distance is the largest, In the case where the delay in entering the platform of the fire train was not taken into account, the ASET was analyzed to be about 800 seconds when the air flow rate was 4 × 833 m³/min. The estimated number of deaths varies greatly depending on the location of the vehicle of fire train, In the case of a fire occurring in a vehicle adjacent to the stairs, it is shown that the increase is up to three times that of the vehicle in the lead. In addition, when the smoke control flow rate increases, the number of fatalities decreases, and the reduction rate of the air supply method rather than the exhaust method increases. When the supply flow rate is 4 × 833 m³/min, the expected number of deaths is reduced to 13% compared to the case where ventilation is not performed. As a result of the risk assessment, it is found that the current social risk assessment criteria are satisfied when smoke control is performed, and the number of deaths is the flow rate 4 × 833 m³/min when smoke control is performed at 29.9 people in 10,000 year, It was analyzed that it decreased to 4.36 people.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1165-1171
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• 1998

Background: All currently available mechanical and bioprosthetic valves are associated with various types of deterioration leading to dysfunction and/or valvular complications. Reoperation on prosthetic heart valves is increasingly under consideration for both clinical and prophylactic indications. This review was conducted to determine the factors affecting the risk of reoperation for prosthetic valve replacement. Material and method: From January 1985 to July 1996, 124 patients underwent reoperation on prosthetic heart valves, and 3 patients had a second valve reoperation. The causes of reoperation were prosthetic valve failure(96 cases, 77.4%), prosthetic valve thrombosis(16 cases, 12.9%), prosthetic valve endocarditis(7 cases, 5.6%) and paravalvular leak(5 cases, 4.1%). This article is based on the analysis of the experience with particular emphasis on the preoperative risks affecting the outcome of the reoperation. Result: Overall hospital mortality rate was 8.9%(11/124). Low cardiac output was the most common cause of death(70.6%). Left ventricular systolic dimension(p=0.001), New York Heart Association functional class IV(p=0.003) and serum creatinine level(p=0.007) were the independent risk factors, but age, sex and cardiothoracic ratio did not have any influence on the operative mortality. Follow-up period was ranged from 3 to 141 months (mean, 50.6 months). A late mortality rate was 1.8%. Conclusion: The surgical risk of reoperation on heart valve prostheses in the advanced NYHA class patients is higher, therefore reoperation is recommended before the hemodynamic impairment become severe.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.328-334
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• 2004

There are only limited numbers of reports about long-term results of tricuspid valve replacement(TVR) with bioprosthetic and mechanical prostheses. We analyzed risk factors for tricuspid valve replacement and compared long-term clinical results of bioprosthetic and mechanical valves in tricuspid position. Material and Method: We reviewed 77 cases of TVR, which were performed between October 1978 and December 1996. Mean age was 38.8 15.9 years. Bioprostheses were implanted in 26 cases and mechanical prostheses were implanted in 51 cases. Result The operative mortality was 15.6% and late mortality was 12.3%. Survival for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 81.3% vs. 100%, 66.1% vs. 100%, 60.6% vs. 100% (p=0.0175). Free from valve related re-operation for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 100% vs. 93.9%, 100% vs. 93.9% and 58.3% vs. 93.9% (p=0.3274). Linealized incidences of valve related re-operation for bioprosthetic and mechanical valve group was 2.27 %/patient-years and 1.10 %/patient-years. Risk factor analysis showed that presence of preoperative ascites, hepatomegaly larger than 2 finger breaths, poor preoperative NYHA functional class and number of tricuspid valve replacement were risk factors for early mortality, and the use of bioprosthetic valve and number of open heart surgery were risk factors for late mortality. Conclusion: Long-term survival of mechanical valve was superior to bioprosthetic valve in tricuspid position. We recommend mechanical valve in tricuspid position if the patient can be closely followed up.

• The Korean Journal of Applied Statistics
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• v.31 no.4
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• pp.529-538
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• 2018

Tuberculosis causes high morbidity and mortality. However, Korea still has the highest tuberculosis (TB) incidence and mortality among OECD countries despite decreasing incidence and mortality due to the development of modern medicine. Korea has now implemented various policy projects to prevent and control tuberculosis. This study analyzes the effects of public-private mix (PPM) tuberculosis control program on treatment outcomes and identifies the factors that affecting the success of TB treatment. We analyzed 130,000 new tuberculosis patient cohort from 2012 to 2015 using data of tuberculosis patient reports managed by the Disease Control Headquarters. A cumulative incidence function (CIF) compared the cumulative treatment success rates for each factor. We compared the results of the analysis using two popular types of competition risk models (cause-specific Cox's proportional hazards model and subdistribution hazard model) that account for the main event of interest (treatment success) and competing events (death).