Korea Seroprevalence Study of Monitoring of SARS-COV-2 Antibody Retention and Transmission (K-SEROSMART): findings from national representative sample.

OBJECTIVES: We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS: In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS: In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS: The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Health-related quality of life using WHODAS 2.0 and associated factors 1 year after stroke in Korea: a multi-centre and cross-sectional study.

BACKGROUND: Little is known about the self-perceived level of disability of stroke survivors in the community. We aimed to characterise Health-related quality of life (HRQoL) 1 year after stroke and investigate how sociodemographic and stroke-related factors and medical adherence explain the self-perceived level of disability in a Korean stroke population. METHODS: This was a multicentre cross-sectional study. A total of 382 ischaemic stroke survivors at 1 year after onset from 11 university hospitals underwent a one-session assessment, including socioeconomic variables, the modified Rankin Scale (mRS), various neurological sequelae, the Morisky, Green and Levin-Medication Adherence Questionnaire (MGL), and the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) 36-items. The relationship between disability and different variables was analysed using ordinal logistic regression. RESULTS: The prevalence of disability based on global WHODAS 2.0 was 62.6% (mild, 41.6%; moderate, 16.0%; severe, 5.0%). The prevalence of severe disability was higher in participation in society (16.8%) and getting around (11.8%) than in other domains. Low MGL- motivation was the only factor determining a significant association between all six domains of disability after adjustment. Different predictors for specific domains were age, mRS, dysarthria, trouble seeing, cognition problems, and MGL-motivation for understanding and communicating; age, recurrent stroke, mRS, hemiplegia, facial palsy, general weakness, and MGL-motivation for getting around; age, education, mRS, hemiplegia, and MGL-motivation for self-care; education, recurrent stroke, hemiplegia, dysarthria, and MGL-motivation for getting along with people; age, education, income, mRS, hemiplegia, dysarthria, MGL-knowledge, and MGL-motivation for life activities; living without a spouse, mRS, hemiplegia, dysarthria, trouble seeing, cognition problems, general weakness, and MGL-motivation for participation in society. CONCLUSIONS: Self-perceived disability according to the WHODAS 2.0 at 1 year after stroke was highly prevalent. Each disability domain showed a different prevalence and associated factors. Interventions promoting medical adherence to motivation seemed to help achieve high HRQoL in all domains.

Gout as a risk factor for osteoporosis: A Korean population-based study.

Uric acid acts as both an antioxidant and a pre-oxidant that induces oxidative stress; thus, it plays a paradoxical role in inflammation. However, the effect of gout, a hallmark of hyperuricemia, on osteoporosis remains unclear. Therefore, this study aimed to investigate the association between gout and osteoporosis. This retrospective cohort study used data from the Korean National Health Insurance Service Database. In total, 628,565 participants who were diagnosed with gout and prescribed medications for gout for at least 90 days were selected. The control cohort included patients with no history of gout or use of gout medication. Age and sex 1:1 propensity score matching and Cox proportional hazards models were used to investigate risk factors for osteoporosis. In total, 305,810 patients with gout met the inclusion criteria. Compared with the control group, both men and women with gout showed an increased incidence rate ratio of osteoporosis. In the stratified analysis by age, patients with gout showed an increased incidence rate ratio for osteoporosis in all age groups, except for those over 80 years of age (P < .001). Gout showed an increased hazard ratio of 1.48 (95% CI: 1.45-1.51, P < .001). The female sex has also been identified as a risk factor for osteoporosis. Patients in their 70s had the highest HR. Gout is significantly associated with the risk of osteoporosis. In particular, the results of this study showed that the incidence of osteoporosis increased up to four times in male patients in their 20s with gout compared to without gout.

Recurrence risk prediction of acute coronary syndrome per patient as a personalized ACS recurrence risk: a retrospective study.

Acute coronary syndrome (ACS) has been one of the most important issues in global public health. The high recurrence risk of patients with coronary heart disease (CHD) has led to the importance of post-discharge care and secondary prevention of CHD. Previous studies provided binary results of ACS recurrence risk; however, studies providing the recurrence risk of an individual patient are rare. In this study, we conducted a model which provides the recurrence risk probability for each patient, along with the binary result, with two datasets from the Korea Health Insurance Review and Assessment Service and Chungbuk National University Hospital. The total data of 6,535 patients who had been diagnosed with ACS were used to build a machine learning model by using logistic regression. Data including age, gender, procedure codes, procedure reason, prescription drug codes, and condition codes were used as the model predictors. The model performance showed 0.893, 0.894, 0.851, 0.869, and 0.921 for accuracy, precision, recall, F1-score, and AUC, respectively. Our model provides the ACS recurrence probability of each patient as a personalized ACS recurrence risk, which may help motivate the patient to reduce their own ACS recurrence risk. The model also shows that acute transmural myocardial infarction of an unspecified site, and other sites and acute transmural myocardial infarction of an unspecified site contributed most significantly to ACS recurrence with an odds ratio of 97.908 as a procedure reason code and with an odds ratio of 58.215 as a condition code, respectively.

Incidence of acute cholecystitis underwent cholecystectomy in incidence dialysis patients: a nationwide population-based cohort study in Korea.

BACKGROUND: Patients on dialysis have numerous gastrointestinal problems related to uremia, which may represent concealed cholecystitis. We investigated the incidence and risk of acute cholecystitis in dialysis patients and used national health insurance data to identify acute cholecystitis in Korea. METHODS: The Korean National Health Insurance Database was used, with excerpted data from the insurance claim of the International Classification of Diseases code of dialysis and acute cholecystitis treated with cholecystectomy. We included all patients who commenced dialysis between 2004 and 2013 and selected the same number of controls via propensity score matching. RESULTS: A total of 59,999 dialysis and control patients were analyzed; of these, 3,940 dialysis patients (6.6%) and 647 controls (1.1%) developed acute cholecystitis. The overall incidence of acute cholecystitis was 8.04-fold higher in dialysis patients than in controls (95% confidence interval, 7.40-8.76). The acute cholecystitis incidence rate (incidence rate ratio, 23.13) was especially high in the oldest group of dialysis patients (aged ≥80 years) compared with that of controls. Dialysis was a significant risk factor for acute cholecystitis (adjusted hazard ratio, 8.94; 95% confidence interval, 8.19-9.76). Acute cholecystitis developed in 3,558 of 54,103 hemodialysis patients (6.6%) and in 382 of 5,896 patients (6.5%) undergoing peritoneal dialysis. CONCLUSION: Patients undergoing dialysis had a higher incidence and risk of acute cholecystitis than the general population. The possibility of a gallbladder disorder developing in patients with gastrointestinal problems should be considered in the dialysis clinic.

Trend of lung cancer surgery, hospital selection, and survival between 2005 and 2016 in South Korea.

BACKGROUND: Studies on the clinical implication of hospital selection for patients with lung cancer are few. Therefore, this study aimed to analyze 2005-2016 data from the Korean national database to assess annual trends of lung cancer surgery and clinical outcomes according to hospital selection. METHODS: Data of 212 554 patients with lung cancer who underwent upfront surgery were screened. Trends according to sex, age, residence, and income were examined. Descriptive statistics were performed, and ptrend values were estimated. The association between survival and hospital selection was assessed using the log-rank test. A multivariate Cox regression analysis was also performed. RESULTS: A total of 49 021 patients were included in this study. Surgery was prevalent among men, patients aged 61-75 years, capital area residents, and high-income patients. However, with the increasing rate of surgery among women, patients aged ≥76 years, city residents, and middle-income patients, the current distribution of lung cancer surgery could change. The rate of lobectomy among these groups increased. All patients, except those in capital areas, preferred a hospital outside their area of residence (HOR); the number of patients with this tendency also increased. However, this trend was not observed among low-income patients and those aged ≥76 years. There were significant differences in survival according to hospital selection. CONCLUSIONS: The trend of lung cancer surgery is changing. The current medical system is effective in providing lobectomy for patients including women, aged ≥76 years, city residents, and middle-income. Increasing tendency to choose an HOR requires further study.

Clinical Association between Gout and Parkinson's Disease: A Nationwide Population-Based Cohort Study in Korea.

Background and Objectives: This retrospective cohort study aimed to investigate the association between gout and Parkinson's disease (PD) in Korea. Materials and Methods: Overall, 327,160 patients with gout and 327,160 age- and sex-matched controls were selected from the Korean National Health Insurance Service (NHIS) database. PD incidence was evaluated by reviewing NHIS records during the period from 2002 to 2019. Patients with a diagnosis of gout (International Classification of Diseases-10 (ICD-10), M10) who were prescribed medications for gout, including colchicine, allopurinol, febuxostat, and benzbromarone for at least 90 days were selected. Patients with PD who were assigned a diagnosis code (ICD-G20) and were registered in the rare incurable diseases (RID) system were extracted. Results: During follow-up, 912 patients with gout and 929 control participants developed PD. The incidence rate (IR) of overall PD (per 1000 person-years) was not significantly different between both groups (0.35 vs. 0.36 in gout and control groups, respectively). The incidence rate ratio (IRR) was 0.98 (95% CI: 0.89-1.07). The cumulative incidence of PD was not significantly different between the groups. No association between gout and PD was identified in univariate analysis (HR = 1.00, 95% CI: 0.91-1.10, p = 0.935). HR increased significantly with old age (HR = 92.08, 198, and 235.2 for 60-69 years, 70-79 years, and over 80 years, respectively), female sex (HR = 1.21, 95% CI: 1.07-1.37, p = 0.002), stroke (HR = 1.95, 95% CI: 1.76-2.16, p < 0.001), and hypertension (HR = 1.16, 95% CI: 1.01-1.34, p = 0.04). Dyslipidemia exhibited an inverse result for PD (HR = 0.6, 95% CI: 0.52-0.68, p < 0.001). Conclusions: This population-based study did not identify an association between gout and PD. Age, female sex, stroke, and hypertension were identified as independent risk factors for PD, and dyslipidemia demonstrated an inverse result for PD.

The Nationwide Incidence of Retinal Vein Occlusion Following Dialysis due to End-stage Renal Disease in Korea, 2004 through 2013.

BACKGROUND: We investigated the incidence and risk of retinal vein occlusion (RVO) in end-stage renal disease (ESRD) patients on dialysis in Korea. METHODS: In this nationwide cohort study, we used Korean National Health Insurance Service data between 2004 and 2013 for analysis. ESRD patients who started dialysis from 2004 to 2013 and an equal number of controls were selected through propensity score matching. RVO incidence in both cohorts were calculated for 2004-2013 using washout data from 2003. The multivariable Cox proportional hazards model was used to assess the risk of RVO in dialysis cohort. The Kaplan-Meier method was used to generate the cumulative RVO incidence curve. Whether the dialysis modality affects the development of RVO was also evaluated. RESULTS: In this study, 74,551 ESRD patients on dialysis and the same number of controls were included. The incidence of RVO was significantly higher in the dialysis cohort than in the control cohort (dialysis = 7.3/1,000 person-years [PY]; control = 1.9/1,000 PY; P < 0.001). The cumulative-incidence of RVO was also significantly higher in the dialysis cohort than in the control cohort (P < 0.001; log-rank test). However, there was no significant difference in the incidence of RVO between the two dialysis methods (P = 0.550; log-rank test). CONCLUSION: This study provided epidemiological evidence that receiving dialysis for ESRD could increase the risk of developing RVO. We also found a rapid increase in the incidence of RVO with a longer dialysis period. These results strengthen the relationship between retinal vascular disease and renal function.

THE NATIONWIDE INCIDENCE OF RETINAL ARTERY OCCLUSION FOLLOWING DIALYSIS AS A RESULT OF END-STAGE RENAL DISEASE: 2004 Through 2013.

PURPOSE: To examine the incidence and risk of retinal artery occlusion (RAO) in patients who have undergone dialysis in Korea. METHODS: A nationwide, population-based study using South Korean national health insurance data from 2004 to 2013 was used for analysis. All patients who began dialysis between 2004 and 2013 and the same number of control subjects were selected via propensity score matching. The incidence of RAO in the dialysis and control cohorts was calculated for 2004 to 2013 using washout data from 2003. The multivariable Cox proportional hazards model was used to evaluate the risk of developing RAO in dialysis patients. Cumulative RAO incidence curves were generated using the Kaplan-Meier method. Whether dialysis modalities influenced the incidence of RAO was also evaluated. RESULTS: Seventy-six thousand seven hundred and eighty-two end-stage renal disease patients on dialysis were included in the dialysis cohort, and 76,782 individuals were included in the control cohort. During the study period, 293 patients in the dialysis cohort and 99 patients in the control cohort developed RAO. The person-years incidence of RAO was significantly higher in the dialysis cohort than in the control cohort (dialysis = 1.1/1,000 person-years; control = 0.3/1,000 person-years; P < 0.001). The incidence of RAO was not significantly different between the two methods of dialysis (hemodialysis vs. peritoneal dialysis; P = 0.25, log-rank test). CONCLUSION: The current study provided epidemiological evidence that undergoing dialysis for end-stage renal disease was associated with an increased risk of developing RAO. The incidence of RAO rapidly increased as the duration of dialysis increased. These results strengthen the significant role of the renal function in retinal vascular disease.

Trends in Axillary Surgery for Treating Ductal Carcinoma In Situ: A Korean Population-based Study.

PURPOSE: Ductal carcinoma in situ (DCIS) is common in South Korea. We evaluated the patterns of axillary surgery among patients with DCIS to highlight the need for compliance with the updated national guidelines. We also evaluated whether sentinel lymph node biopsy (SLNB) was performed in accordance with the national guidelines. METHODS: The Korean Health Insurance Review and Assessment Service-National Inpatient Sample database was searched for patients with DCIS (2009-2015) to identify axillary surgery patterns by breast surgery type, year of diagnosis, age at diagnosis, and the location and volume of surgeries for DCIS at the hospital. The rates of SLNB and axillary dissection were compared using descriptive statistics and univariate analyses. Analyses were also conducted using the chi-squared test and multiple logistic regression analysis. RESULTS: We identified 16,315 Korean women who underwent surgery for DCIS, including 11,292 cases of SLNB (69.2%) and 131 cases of axillary lymph node dissection (0.8%). Breast-conserving surgery (BCS) was performed in 10,323 patients (63.3%) with an SLNB rate of 56.0%, while total mastectomy (TM) was performed in 5,992 patients (36.7%), with an SLNB rate of 92.0%. During 2009-2015, the SLNB rate during TM increased from 88.23% to 92.80%. SLNB was influenced by hospital region and surgical volume, and hospitals performing low volumes of surgeries were significantly more likely to perform SLNB regardless of the surgery type (odds ratio, 1.372; 95% confidence interval, 1.265-1.488). CONCLUSION: Although the Korean guidelines recommend SLNB for all TM procedures and select BCS procedures for DCIS, relatively high rates of SLNB were performed for BCS, and there was inter-hospital variability in performing SLNB. Improved compliance with the guidelines by the surgeons is critical for Korean patients with DCIS.

Renin-angiotensin system modulators and other risk factors in COVID-19 patients with hypertension: a Korean perspective.

BACKGROUND: While hypertension is the most common comorbid condition in patients with coronavirus disease 2019 (COVID-19) in Korea, there is a lack of studies investigating risk factors in COVID-19 patients with hypertension in Korea. In this study, we aimed to examine the effects risk factors in hypertensive Korean COVID-19 patients. METHODS: We selected patients from the database of the project #OpenData4Covid19. This information was linked to their 3-year historical healthcare data. The severity of the disease was classified into five levels. We also clustered the levels into two grades. RESULTS: The risk factors associated with COVID-19 severity were old age, diabetes mellitus, cerebrovascular disease, chronic obstructive pulmonary disease (COPD), malignancy, and renal replacement therapy. The use of angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) both before and after a diagnosis of COVID-19 were not associated with COVID-19 severity. A multivariate analysis revealed that old age, male sex, diabetes mellitus, and renal replacement therapy were risk factors for severe COVID-19. CONCLUSION: The results suggest that in hypertensive patients with COVID-19, older age, male sex, a diagnosis of diabetes mellitus, and renal replacement therapy were risk factors for a severe clinical course. In addition, the use of ARBs and ACEIs before or after COVID-19 infection did not affect a patient's risk of contracting COVID-19 nor did it contribute to a worse prognosis for the disease. These results highlighted that precautions should be considered for hypertensive patients with those risk factors and do not support discontinuation of ARBs and ACEIs during COVID-19 pandemic.

Disparities in the Diagnosis, Treatment, and Survival Rate of Cervical Cancer among Women with and without Disabilities.

INTRODUCTION: Not much is known regarding the disparities in cancer care between women with and without disabilities. OBJECTIVES: The aim of this study was to investigate the potential disparities in the diagnosis, treatment, and survival of women with cervical cancer with and without disabilities. METHODS: We performed a retrospective cohort study and linked the National Disability Database, Korean Central Cancer Registry, and Korean National Health Insurance claims database. Charlson comorbidity index was used for adjusting the comorbidity. The study population comprised 3 185 women with disabilities (physical/brain, communication, mental, cardiopulmonary, and other impairment) who were diagnosed with cervical cancer and 13 582 age- and sex-matched women without disability who were diagnosed with cervical cancer for comparison. RESULTS: Distant metastatic stage (7.7% vs 3.7%) and unknown stage (16.1% vs 7.0%) were more common in cervical cancer women with grade 1 disabilities, compared with women without disabilities. Women with cervical cancer with disabilities were less likely to undergo surgery (adjusted odds ratio (aOR) 0.81, 95% confidence interval (CI) 0.73-0.90) or chemotherapy (aOR 0.86, 95% CI 0.77-0.97). Lower rate of surgery was more evident in patients with physical/brain impairment (aOR 0.46, 95% CI 0.37-0.58) and severe mental impairment (aOR 0.57, 95% CI 0.41-0.81). The overall mortality risk was also higher in patients with disabilities (adjusted hazard ratio (aHR) 1.36, 95% CI 1.25-1.48). CONCLUSION: Women with cervical cancer with disabilities, especially with severe disabilities, were diagnosed at later stages, received less treatment, and had higher mortality rates, compared with patients who lacked disabilities. Social support and policies, along with education for women with disabilities, their families, and healthcare professionals, are needed to improve these disparities.

The Incidences and Characteristics of Various Cancers in Patients on Dialysis: a Korean Nationwide Study.

BACKGROUND: The numbers of patients on dialysis and their life expectancies are increasing. Reduced renal function is associated with an increased risk of cancer, but the cancer incidence and sites in dialysis patients compared with those of the general population require further investigation. We investigated the incidences of various cancers in dialysis patients in Korea and used national health insurance data to identify cancers that should be screened in dialysis clinics. METHODS: We accessed the Korean National Health Insurance Database and excerpted data using the International Classification of Disease codes for dialysis and malignancies. We included all patients who commenced dialysis between 2004 and 2013 and selected the same number of controls via propensity score matching. RESULTS: A total of 48,315 dialysis patients and controls were evaluated; of these, 2,504 (5.2%) dialysis patients and 2,201 (4.6%) controls developed cancer. The overall cancer risk was 1.54-fold higher in dialysis patients than in controls (adjusted hazard ratio, 1.71; 95% confidence interval, 1.61-1.81). The cancer incidence rate (incidence rate ratio [IRR], 3.27) was especially high in younger dialysis patients (aged 0-29 years). The most common malignancy of end-stage renal disease patients and controls was colorectal cancer. The major primary cancer sites in dialysis patients were liver and stomach, followed by the lung, kidney, and urinary tract. Kidney cancer exhibited the highest IRR (6.75), followed by upper urinary tract (4.00) and skin cancer (3.38). The rates of prostate cancer (0.54) and oropharyngeal cancer (0.72) were lower than those in the general population. CONCLUSION: Dialysis patients exhibited a higher incidence of malignancy than controls. Dialysis patients should be screened in terms of colorectal, liver, lung, kidney and urinary tract malignancies in dialysis clinics.

Cost-Benefit Analysis of Malaria Chemoprophylaxis and Early Diagnosis for Korean Soldiers in Malaria Risk Regions.

BACKGROUND: Chemoprophylaxis has been used to prevent malaria among soldiers and secondary transmission, as it effectively facilitates a decline in disease occurrence and secondary prevention. However, poor compliance and decreased risk of exposure to malaria necessitate that control strategies be reestablished. METHODS: To predict the incidence of malaria according to a control strategy, we proposed a mathematical model for its transmission using epidemiological data from 2010 to 2012. The benefit component included in the analyses was the averted cost with each control strategy, and the cost components were the cost of implementing chemoprophylaxis and early diagnosis. RESULTS: The chemoprophylaxis regimen with hydroxychloroquine sulfate and primaquine was Intervention 1, the regimen with primaquine only was Intervention 2, and diagnosis with a rapid diagnostic test (RDT) kit within 5 days of fever was Intervention 3. The simulation indicated that the combined control program with chemoprophylaxis and early diagnosis would be the most effective strategy, whereas sole early diagnosis would be the least effective strategy. However, the cost-benefit ratio of chemoprophylaxis was less than Intervention 1, irrespective of the varying range of chemoprophylaxis compliance, and that of early diagnosis was more than Intervention 1, regardless of the varying early diagnosis rate and demand for the RDT kit. Although chemoprophylaxis would be more effective at reducing the incidence of malaria than early diagnosis, it is less economical due to the higher cost. CONCLUSION: Our results support the introduction of early diagnosis with a RDT kit to control malaria in the Republic of Korea Army.

End-stage Renal Disease and Risk of Active Tuberculosis: a Nationwide Population-Based Cohort Study.

BACKGROUND: The converging epidemics of tuberculosis (TB) and end-stage renal disease (ESRD) have generated a significant public health burden, however, previous studies have been limited to a small number of patients. This nationwide cohort study aimed to assess the rate of developing active TB among patients receiving dialysis for ESRD. METHODS: The Korean national health insurance database was used to identify patients receiving dialysis for new-onset ESRD during 2004-2013, who were propensity score matched to an equivalent number of non-dialysis subjects from the general population. The incidences of active TB in the ESRD and control cohorts were calculated for 2004-2013, and multivariable Cox proportional hazards model was used to evaluate the ESRD-related risk of active TB. RESULTS: During 2004-2013, 59,584 patients received dialysis for newly diagnosed ESRD. In the dialysis and control cohorts, 457 (0.8%) and 125 (0.2%) cases of active TB were detected, respectively. Patients with ESRD were associated with a significantly higher risk of active TB compared to the controls (incidence rate ratio, 4.80). The ESRD cohort had an independently elevated risk of active TB (adjusted hazard ratio, 4.39; 95% confidence interval, 3.60-5.37). CONCLUSION: We found that patients receiving dialysis for ESRD had an elevated risk of active TB. These results highlight the need for detailed and well-organised guidelines for active TB screening among patients with ESRD.

ESTIMATION OF THE CUMULATIVE EXPOSURE FREQUENCY AND CUMULATIVE EFFECTIVE DOSE OF DIAGNOSTIC MEDICAL RADIATION IN THE KOREAN POPULATION FROM 2002 TO 2010.

Along with increase in the frequency and exposure dose from the diagnostic medical radiation procedures, the public's interest in radiation exposure has also been growing. In this study, in order to estimate the Cumulative Exposure Frequency and the cumulative effective dose of diagnostic medical radiation in the Korean population, we included 680 diagnostic medical radiation procedure codes of the Health Insurance Review & Assessment Service's health insurance medical expenses data and adopted the effective dose data from the 2008 report of the United Nations Scientific Committee on the Effects of Atomic Radiation. We combined the data of one million individuals in the national sample cohort database (2002-10) of the National Health Insurance Service. The results revealed that 93.2% (917 972) of the subjects were exposed to diagnostic medical radiation at least once in the past nine years, and the Cumulative Exposure Frequency was 17 286.4 per 1000 individuals with a cumulative effective dose of 5.7 (±17.8) mSv per person. Additionally, 93.1% (854 480) of the subjects had a cumulative effective dose less than 20 mSv, and 0.7% (6139) had a dose that exceeded 100 mSv (extreme), showing that the dosage level was mostly low. However, the number of individuals whose exposure exceeded 100 mSv/y increased 28-fold, from 18 in 2002 to 500 in 2010. In addition, the size of increase also grew each year, suggesting that cancer occurrence due to diagnostic medical radiation may have also increased. In order determine the causal relationship between cancer occurrence and diagnostic medical radiation and setup a guideline for exposure, it is necessary to monitor individual cumulative exposure doses nation-wide and follow up on heavily exposed individuals for an extended period of time.

Public Awareness of Stroke and Its Predicting Factors in Korea: a National Public Telephone Survey, 2012 and 2014.

The aim of this study was to investigate time trends in the public awareness of stroke and its predicting factors. The target population was 9,600 community-dwelling adults, aged 19-79 years, in 16 metropolitan cities and provinces in Korea. The survey samples in 2012 and 2014 were selected separately (entirely different sets of subjects) using a proportionate quota sampling method. Information concerning knowledge of stroke and demographics was collected by trained telephone interviewers using random digit dialing. After excluding subjects with a non-response or refusal to answer any question, the analyses included 8,191 subjects in 2012 and 8,127 subjects in 2014. Respondents' awareness of stroke warning signs (numbness or weakness, difficulty speaking or understanding speech, dizziness, visual impairment, and severe headache) was highest for difficulty speaking or understanding speech (80.9% in 2012 and 86.4% in 2014). There were significant increases in the proportion of respondents understanding the appropriate action (i.e., calling an ambulance) at the time of stroke occurrence (59.6% to 67.1%), and in the proportion aware of the general need for prompt treatment (86.7% to 89.8%). In multivariable logistic regression analysis, older age, higher education level, higher household income, current non-smoking, exposure to stroke-related public relations materials, and experience of stroke education were significantly associated with both high knowledge of stroke warning signs and awareness of the need for prompt treatment. Between 2012 and 2014, the public's awareness of stroke increased significantly. More specialized interventions, including public relations materials and education, should focus on subgroups who have lower stroke knowledge.

Cost-Utility Analysis of Screening Strategies for Diabetic Retinopathy in Korea.

This study involved a cost-utility analysis of early diagnosis and treatment of diabetic retinopathy depending on the screening strategy used. The four screening strategies evaluated were no screening, opportunistic examination, systematic fundus photography, and systematic examination by an ophthalmologists. Each strategy was evaluated in 10,000 adults aged 40 yr with newly diagnosed diabetes mellitus (hypothetical cohort). The cost of each strategy was estimated in the perspective of both payer and health care system. The utility was estimated using quality-adjusted life years (QALY). Incremental Cost Effectiveness Ratio (ICER) for the different screening strategies was analyzed. After exclusion of the weakly dominating opportunistic strategy, the ICER of systematic photography was 57,716,867 and that of systematic examination by ophthalmologists was 419,989,046 from the perspective of the healthcare system. According to the results, the systematic strategy is preferable to the opportunistic strategy from the perspective of both a payer and a healthcare system. Although systematic examination by ophthalmologists may have higher utility than systematic photography, it is associated with higher cost. The systematic photography is the best strategy in terms of cost-utility. However systematic examination by ophthalmologists can also be a suitable policy alternative, if the incremental cost is socially acceptable.

Factors affecting the validity of self-reported data on health services from the community health survey in Korea.

PURPOSE: As a follow-up for the validity study of Community Health Surveys (CHSs), the purpose of this study was to evaluate the factors affecting the accuracy of CHSs by investigating subjects' characteristics. MATERIALS AND METHODS: We used data from 11,217 participants (aged 19 years or older) who had participated in the CHS, conducted by a local government in 2008 and analyzed the variables affecting the sensitivity and specificity of hospitalization and outpatient visit. RESULTS: Multivariate logistic regression analysis showed that, factors related with the sensitivity of hospitalization and outpatient visit questions were gender, age, marital status, chronic diseases, medical checkup, the subjective health status and necessary medical services. Factors related with the specificity were gender, marital status, educational background, chronic diseases, medical checkup, alcohol consumption, necessary medical services and sadness. CONCLUSION: This study revealed the subject-related factors associated with the validity of the CHS. Efforts to improve the sensitivity and the specificity from self-report questionnaires should consider how the characteristics of subjects may affect their responses.