Background/Aims: This study aimed to investigate the effect of hepatocellular carcinoma (HCC) surveillance using the Korea National Liver Cancer Screening Program on the receipt of curative treatment for HCC and mortality in patients with chronic liver disease. Methods: This population-based cohort study from the Korean National Health Insurance Service included 2003 to 2015 claims data collected from 1,209,825 patients aged ≥40 years with chronic hepatitis B, chronic hepatitis C, and liver cirrhosis. Patients were divided according to HCC surveillance using ultrasonography and serum alpha-fetoprotein every 6–12 months. The study outcomes were the receipt of curative treatment (surgical resection, radiofrequency ablation, or liver transplantation) and all-cause mortality. Results: The study population consisted of 1,209,825 patients with chronic hepatitis B, chronic hepatitis C, and liver cirrhosis (median age, 52.0 years; interquartile range, 46–55 years; 683,902 men [56.5%]). The proportion of participants who underwent HCC surveillance was 52.7% (n=657,889). During 10,522,940 person-years of follow-up, 74,433 HCC cases developed, including 36,006 patients who underwent curative treatment. The surveillance group had a significantly higher proportion of curative treatment for HCC than the non-surveillance group after adjusting for confounding factors (adjusted hazard ratio [HR], 5.64; 95% confidence interval [CI], 5.48–5.81). The surveillance group had a significantly lower mortality rate than the non-surveillance group (adjusted HR, 0.56; 95% CI, 0.55–0.56). Conclusions HCC surveillance using the national screening program in patients with chronic viral hepatitis or liver cirrhosis provides better opportunity for curative treatment for HCC and improves overall survival.

This study was conducted as a pilot project to evaluate the feasibility of building an integrate dementia platform converging preexisting dementia cohorts from several variable levels. The following four cohorts were used to develop this pilot platform: 1) Clinical Research Center for Dementia of South Korea (CREDOS), 2) Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s disease (K-BASE), 3) Environmental Pollution-induced Neurological Effects (EPINEF) study, and 4) a prospective registry in Dementia Platform Korea project (DPKR). A total of 29916 patients were included in the platform with 348 integrated variables. Among participants, 13.9%, 31.5%, and 44.2% of patients had normal cognition, mild cognitive impairment, and dementia, respectively. The mean age was 72.4 years. Females accounted for 65.7% of all patients. Those with college or higher education and those without problems in reading or writing accounted for 12.3% and 46.8%, respectively. Marital status, cohabitation, family history of Parkinson’s disease, smoking and drinking status, physical activity, sleep status, and nutrition status had rates of missing information of 50% or more. Although individual cohorts were of the same domain and of high quality, we found there were several barriers to integrating individual cohorts, including variability in study variables and measurements. Although many researchers are trying to combine pre-existing cohorts, the process of integrating past data has not been easy. Therefore, it is necessary to establish a protocol with considerations for data integration at the cohort establishment stage.

Nonpharmaceutical interventions (e.g., social distancing) are recommended to prevent the spread of respiratory viruses. However, few epidemiological studies have assessed whether social distancing in actual settings reduces the disease burden of severe acute respiratory infections (SARIs) in the general population. Accordingly, we aimed to assess associations between nationwide social distancing for coronavirus disease 2019 (COVID-19) and non-COVID-19 SARIs. We collected data on SARI epidemiologic characteristics recorded from January 2018 through December 2020 from the nationwide sentinel SARI surveillance data maintained by the Korea Disease Control and Prevention Agency. The number of SARIs per 1000 hospitalized patients decreased significantly to 18.61, 18.15, and 6.25 in 2018, 2019, and 2020 (p<0.001), respectively, during the surveillance period of 3 years. The number of intensive care unit admissions associated with SARIs per 1000 hospitalized patients was 0.83, 0.69, and 0.54 in 2018, 2019, and 2020 (p< 0.001), respectively, and the number of SARI-associated mortalities per 1000 patients was 0.42, 0.29, and 0.27 in 2018, 2019, and 2020 (p<0.001), respectively. Moreover, SARIs had two peak seasons in 2 years of the surveillance period (2018 and 2019). However, seasonality was not observed since social distancing was initiated. Our sentinel surveillance data demonstrated a remarkable reduction in SARI disease burden and a change in seasonality following the implementation of nationwide social distancing. Accordingly, we suggest that social distancing could be effective in forthcoming seasonal epidemics of non-COVID-19 origin, although the impact thereof on other aspects of society needs to be carefully considered.

This study was conducted as a pilot project to evaluate the feasibility of building an integrate dementia platform converging preexisting dementia cohorts from several variable levels. The following four cohorts were used to develop this pilot platform: 1) Clinical Research Center for Dementia of South Korea (CREDOS), 2) Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s disease (K-BASE), 3) Environmental Pollution-induced Neurological Effects (EPINEF) study, and 4) a prospective registry in Dementia Platform Korea project (DPKR). A total of 29916 patients were included in the platform with 348 integrated variables. Among participants, 13.9%, 31.5%, and 44.2% of patients had normal cognition, mild cognitive impairment, and dementia, respectively. The mean age was 72.4 years. Females accounted for 65.7% of all patients. Those with college or higher education and those without problems in reading or writing accounted for 12.3% and 46.8%, respectively. Marital status, cohabitation, family history of Parkinson’s disease, smoking and drinking status, physical activity, sleep status, and nutrition status had rates of missing information of 50% or more. Although individual cohorts were of the same domain and of high quality, we found there were several barriers to integrating individual cohorts, including variability in study variables and measurements. Although many researchers are trying to combine pre-existing cohorts, the process of integrating past data has not been easy. Therefore, it is necessary to establish a protocol with considerations for data integration at the cohort establishment stage.

Nonpharmaceutical interventions (e.g., social distancing) are recommended to prevent the spread of respiratory viruses. However, few epidemiological studies have assessed whether social distancing in actual settings reduces the disease burden of severe acute respiratory infections (SARIs) in the general population. Accordingly, we aimed to assess associations between nationwide social distancing for coronavirus disease 2019 (COVID-19) and non-COVID-19 SARIs. We collected data on SARI epidemiologic characteristics recorded from January 2018 through December 2020 from the nationwide sentinel SARI surveillance data maintained by the Korea Disease Control and Prevention Agency. The number of SARIs per 1000 hospitalized patients decreased significantly to 18.61, 18.15, and 6.25 in 2018, 2019, and 2020 (p<0.001), respectively, during the surveillance period of 3 years. The number of intensive care unit admissions associated with SARIs per 1000 hospitalized patients was 0.83, 0.69, and 0.54 in 2018, 2019, and 2020 (p< 0.001), respectively, and the number of SARI-associated mortalities per 1000 patients was 0.42, 0.29, and 0.27 in 2018, 2019, and 2020 (p<0.001), respectively. Moreover, SARIs had two peak seasons in 2 years of the surveillance period (2018 and 2019). However, seasonality was not observed since social distancing was initiated. Our sentinel surveillance data demonstrated a remarkable reduction in SARI disease burden and a change in seasonality following the implementation of nationwide social distancing. Accordingly, we suggest that social distancing could be effective in forthcoming seasonal epidemics of non-COVID-19 origin, although the impact thereof on other aspects of society needs to be carefully considered.