OBJECTIVES: Measurement of similarities between documents is typically influenced by the sparseness of the term-document matrix employed. Latent semantic indexing (LSI) may improve the results of this type of analysis. METHODS: In this study, LSI was utilized in an attempt to reduce the term vector space of clinical documents and newspaper editorials. RESULTS: After applying LSI, document similarities were revealed more clearly in clinical documents than editorials. Clinical documents which can be characterized with co-occurring medical terms, various expressions for the same concepts, abbreviations, and typographical errors showed increased improvement with regards to a correlation between co-occurring terms and document similarities. CONCLUSIONS: Our results showed that LSI can be used effectively to measure similarities in clinical documents. In addition, correlation between the co-occurrence of terms and similarities realized in this study is an important positive feature associated with LSI.
Abstracting and Indexing as Topic ; Cluster Analysis ; Information Storage and Retrieval ; Periodicals ; Semantics

OBJECTIVE: CDA (Clinical Document Architecture) is a markup standard for clinical document exchange. In order to increase the semantic interoperability of documents exchange, the clinical statements in the narrative blocks should be encoded with code values. Natural language processing (NLP) is required in order to transform the narrative blocks into the coded elements in the level 3 CDA documents. In this paper, we evaluate the accuracy of text mapping methods which are based on NLP. METHODS: We analyzed about one thousand discharge summaries to know their characteristics and focused the syntactic patterns of the diagnostic sections in the discharge summaries. According to the patterns, different rules were applied for matching code values of Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT). RESULTS: The accuracy of matching was evaluated using five-hundred discharge summaries. The precision was as follows: 86.5% for diagnosis, 61.8% for chief complaint, 62.7%, for problem list, and 64.8% for discharge medication. CONCLUSION: The text processing method based on the pattern analysis of a clinical statement can be effectively used for generating CDA entries.
Diagnosis ; Natural Language Processing ; Semantics ; Systematized Nomenclature of Medicine

OBJECTIVES: The purpose of this study was to investigate the effects of query expansion algorithms for MEDLINE retrieval within a pseudo-relevance feedback framework. METHODS: A number of query expansion algorithms were tested using various term ranking formulas, focusing on query expansion based on pseudo-relevance feedback. The OHSUMED test collection, which is a subset of the MEDLINE database, was used as a test corpus. Various ranking algorithms were tested in combination with different term re-weighting algorithms. RESULTS: Our comprehensive evaluation showed that the local context analysis ranking algorithm, when used in combination with one of the reweighting algorithms - Rocchio, the probabilistic model, and our variants - significantly outperformed other algorithm combinations by up to 12% (paired t-test; p < 0.05). In a pseudo-relevance feedback framework, effective query expansion would be achieved by the careful consideration of term ranking and re-weighting algorithm pairs, at least in the context of the OHSUMED corpus. CONCLUSIONS: Comparative experiments on term ranking algorithms were performed in the context of a subset of MEDLINE documents. With medical documents, local context analysis, which uses co-occurrence with all query terms, significantly outperformed various term ranking methods based on both frequency and distribution analyses. Furthermore, the results of the experiments demonstrated that the term rank-based re-weighting method contributed to a remarkable improvement in mean average precision.
Information Storage and Retrieval ; Models, Statistical

Epiglottitis is an uncommon but potentially life threatening infectious disease in young children. And it is rapidly progressing cellulitis of the epiglottis and adjacent structures that has the potential for causing abrupt, complete airway obstruction. The most common cause of acute epiglottitis is Haemophilius influenzae type b(Hib), therefore in USA, the acute epiglottitis is seen less commonly since the wide spread use of immunization against Hib. In Korea, there has been no report of acute epiglottitis caused by known bacterial organism, and a little investigation of the effects of the immunization against Hib, or Hib related respiratory diseases. In this report, we describe two cases of acute epiglottitis caused by Hib, occurred in non-immunized young-male children admitted to Ajou University Hospital. They had visited to the emergency center of Ajou University hospital with the complaints of acute fever, drooling, dysphagia and severe respiratory difficulties. In both cases, we observed the cherry-red colored, severely swollen epiglottis by the direct laryngoscopic examination. Hib was cultured in blood samples from both two cases, and the patients treated successfully by the 3 days of endotracheal intubation and proper antibiotics therapy without any complications such as pneumonia, meningitis, osteomyelitis, or pericarditis.
Airway Obstruction ; Anti-Bacterial Agents ; Cellulitis ; Child ; Communicable Diseases ; Deglutition Disorders ; Emergencies ; Epiglottis ; Epiglottitis* ; Fever ; Haemophilus influenzae type b* ; Haemophilus influenzae* ; Haemophilus* ; Humans ; Immunization ; Influenza, Human ; Intubation, Intratracheal ; Korea ; Meningitis ; Osteomyelitis ; Pericarditis ; Pneumonia ; Sialorrhea

OBJECTIVE: Ubiquitous healthcare (u-Healthcare) is an emerging paradigm in the healthcare environment. One of the most promising applications for u-Healthcare is the ubiquitous home health monitoring system. This paper addresses two significant challenges in the successful application of the ubiquitous home health monitoring system: the uniform integration of measured biosignal data and easy access to monitored biosignal data. METHODS: We used the Medical waveform description Format Encoding Rule (MFER) standard to encode biosignal data. A web-based MFER upload ActiveX control was designed and implemented to transfer MFER files to the central repository server in a near real-time basis. All of the integrated biosignal data were then accessed and managed through the central repository server. RESULTS: We developed a u-House server that can serve as a uniform data transferer to integrate measured biosignal data from u-House homes into the remote central repository server. We developed user-friendly web services that allow users to easily search and view monitored biosignal data. CONCLUSION: The results of this study suggest that the MFER standard can be easily adapted to u-Healthcare systems and that a web-based ubiquitous home health monitoring system has advantages of ubiquitous access and scalability.
Delivery of Health Care

Purpose: The first year of the COVID-19 pandemic in Korea elicited changes in healthcare service utilization. This study aimed to report changes in healthcare service utilization among cancer patients during the first year of the COVID-19 pandemic in Korea. Materials and Methods: We analyzed records from National Health Insurance Service Database and identified cancer patients as those with specific beneficiary codes (“V193” or “V194”) assigned to cancer patients. We calculated percentage changes in the number of patients between 2019 and 2020 based on claims records for outpatient clinic visits, hospitalization, and emergency room visits by month, age group, residential areas, and hospital location. Results: The number of newly diagnosed cancer patients in 2020 decreased by 3.2%, compared to the previous year. The number of patients who visited an outpatient clinic, were hospitalized, and visited the emergency room decreased by 2.6%, 4.0%, and 3.5%, respectively, in 2020, compared to the year 2019. Conclusion During the first year of the COVID-19 pandemic, the number of newly diagnosed cancer patients decreased by 3.2%, compared to the previous year, and their utilization of healthcare services declined significantly after the outbreak of COVID-19.

OBJECTIVES: There is a need for effective processes in healthcare clinics, especially in tertiary hospitals, that consist of a set of complex steps for outpatient care, in order to provide high quality care and reduce the time cost. This study aimed to discover the potential of a process mining technique to determine an outpatient care process that can be utilized for further improvements. METHODS: The outpatient event log was defined, and the log data for a month was extracted from the hospital information system of a tertiary university hospital. That data was used in process mining to discover an outpatient care process model, and then the machine-driven model was compared with a domain expert-driven process model in terms of the accuracy of the matching rate. RESULTS: From a total of 698,158 event logs, the most frequent pattern was found to be "Consultation registration > Consultation > Consultation scheduling > Payment > Outside-hospital prescription printing" (11.05% from a total cases). The matching rate between the expert-driven process model and the machine-driven model was found to be approximately 89.01%, and most of the processes occurred with relative accuracy in accordance with the expert-driven process model. CONCLUSIONS: Knowledge regarding the process that occurs most frequently in the pattern is expected to be useful for hospital resource assignments. Through this research, we confirmed that process mining techniques can be applied in the healthcare area, and through detailed and customized analysis in the future, it can be expected to be used to improve actual outpatient care processes.
Ambulatory Care ; Delivery of Health Care ; Hospital Information Systems ; Humans ; Mining ; Outpatients ; Prescriptions ; Tertiary Care Centers

PURPOSE: This study was performed to investigate the availability of the serum HSP72 and HSP27 as serologic markers of cardiac allograft rejection through rat heterotopic heart transplatation model. METHODS: Inbred Lewis rats were randomly divided into three groups: the allograft heart transplant group, the isograft heart transplant group, and the sham-operated group. Six animals were studied in each group. In allograft heart tranplant group, the Brown Norway rats were used as donors and in isograft heart tranplant group, the Lewis rats were used as donors. The sera of the allograft heart transplanted rats, isograft heart transplanted rats, and sham- operated rats were collected at preoperative time, 3 days after operation and 6 days after operation, and analyzed for HSP72 and HSP27 by Western blots. Quantifications of band densities were carried out by laser densitometer and the results were expressed as % preoperative densities. RESULTS: The levels of serum HSP72 of 3 days and 6 days after heart transplantation significantly increased in the allograft heart transplant group than in the isograft heart transplant group, respectively (160.2+/-44.8% vs. 109.0+/-34.7%, 276.0+/-72.1% vs. 175.0+/-44.2%, P<0.05). The levels of seum HSP27 of 3 days and 6 days after heart transplantation significantly increased in the allograft heart transplant group than in the isograft heart transplant group, respectively (162.3+/-62.7% vs. 118.4+/-37.0%, 235.7+/-67.1% vs. 127.9+/-40.8%, P<0.05). CONCLUSION: It is concluded that serum HSP72 and HSP27 are useful markers to detect the cardiac allograft rejection.
Allografts ; Animals ; Blotting, Western ; Heart Transplantation ; Heart* ; Heat-Shock Proteins ; Humans ; Isografts ; Norway ; Rats* ; Rats, Inbred Lew ; Tissue Donors ; Transplantation

BACKGROUND: The present study aimed to examine the association between cigarette smoking, alcohol consumption and colorectal cancer risk among Korean adults. METHODS: Data from the Korean Multi-center Cancer Cohort between 1993 and 2005 were analyzed. The study population comprised 18,707 subjects aged older than 20 years old. The subjects were followed until December 31, 2011 (median follow-up of 11.2 years). The Cox proportional hazard model was used to estimate the hazard ratio (HR) and 95% confidence intervals of cigarette smoking and alcohol consumption for colorectal cancer risk. RESULTS: In men, longer duration and higher average amount of alcohol consumption were associated with elevated risk of colorectal cancer (HR 1.93 [1.17-3.18] for > or = 30 years of consumption compared to non-drinkers; HR 2.24 [1.31-3.84] for > or = 30 g/d). Former smokers showed a non-significantly elevated risk of colorectal cancer in men. There was no apparent association between alcohol consumption or cigarette smoking and colorectal cancer risk among women. CONCLUSIONS: Alcohol consumption was associated with increased colorectal cancer risk among Korean men, and both a longer duration and a higher amount of consumption were associated with elevated risk.
Adult ; Alcohol Drinking* ; Cohort Studies* ; Colorectal Neoplasms* ; Female ; Follow-Up Studies ; Humans ; Male ; Proportional Hazards Models ; Prospective Studies ; Smoking* ; Tobacco Products*

OBJECTIVES: We aimed to develop a common health information exchange (HIE) platform that can provide integrated services for implementing the HIE infrastructure in addition to guidelines for participating in an HIE network in South Korea. METHODS: By exploiting the Health Level 7 (HL7) Clinical Document Architecture (CDA) and Integrating the Healthcare Enterprise (IHE) Cross-enterprise Document Sharing-b (XDS.b) profile, we defined the architectural model, exchanging data items and their standardization, messaging standards, and privacy and security guidelines, for a secure, nationwide, interoperable HIE. We then developed a service-oriented common HIE platform to minimize the effort and difficulty of fulfilling the standard requirements for participating in the HIE network. The common platform supports open application program interfaces (APIs) for implementing a document registry, a document repository, a document consumer, and a master patient index. It could also be used for testing environments for the implementation of standard requirements. RESULTS: As the initial phase of implementing a nationwide HIE network in South Korea, we built a regional network for workers' compensation (WC) hospitals and their collaborating clinics to share referral and care record summaries to ensure the continuity of care for industrially injured workers, using the common HIE platform and verifying the feasibility of our technologies. CONCLUSIONS: We expect to expand the HIE network on a national scale with rapid support for implementing HL7 and IHE standards in South Korea.
Computer Security ; Computer Systems ; Continuity of Patient Care ; Delivery of Health Care ; Electronic Health Records ; Health Level Seven ; Humans ; Information Services* ; Korea ; Privacy ; Referral and Consultation ; Workers' Compensation