COVID-19 Mortality and Severity in Cancer Patients and Cancer Survivors.

BACKGROUND: We aimed to investigate mortality, severity, and risk of hospitalization in coronavirus disease 2019 (COVID-19) patients with cancer. METHODS: Data of all patients aged 40-79 years from the Korean Disease Control and Prevention Agency-COVID19-National Health Insurance Service who were diagnosed with COVID-19 between January 1, 2020 and March 31, 2022, in Korea were included. After 1:1 propensity score matching, 397,050 patients with cancer and 397,050 patients without cancer were enrolled in the main analysis. A cancer survivor was defined as a patient who had survived 5 or more years since the diagnosis of cancer. Multiple logistic regression analysis was performed to compare the risk of COVID-19 according to the diagnosis of cancer and time since diagnosis. RESULTS: Cancer, old age, male sex, incomplete vaccination against COVID-19, lower economic status, and a higher Charlson comorbidity index were associated with an increased risk of hospitalization, hospitalization with severe state, and death. Compared to patients without cancer, the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for hospitalization, hospitalization with severe state, and death in patients with cancer were 1.09 (1.08-1.11), 1.17 (1.11-1.24), and 1.94 (1.84-2.05), respectively. Compared to patients without cancer, the ORs (95% CIs) for hospitalization in cancer survivors, patients with cancer diagnosed 2-5 years, 1-2 years, and < 1 year ago were 0.96 (0.94-0.98), 1.10 (1.07-1.13), 1.30 (1.25-1.34), and 1.82 (1.77-1.87), respectively; the ORs (95% CIs) for hospitalization for severe disease among these patients were 0.90 (0.85-0.97), 1.22 (1.12-1.32), 1.60 (1.43-1.79), and 2.29 (2.09-2.50), respectively. CONCLUSION: The risks of death, severe state, and hospitalization due to COVID-19 were higher in patients with cancer than in those without; the more recent the diagnosis, the higher the aforementioned risks. Cancer survivors had a lower risk of hospitalization and hospitalization with severe disease than those without cancer.

No increased risk of osteonecrosis of the jaw in osteoporotic patients with dental implants: a nationwide cohort study.

OBJECTIVES: The occurrence of implant-associated osteonecrosis of the jaw (ONJ) has been reported in osteoporotic patients, particularly in association with bisphosphonate therapy. This study aimed to investigate the risk of implant surgery and implant presence for ONJ occurrence in osteoporotic patients longitudinally. METHODS: Based on Korean National Health Information Database, subjects over the age of 65 who were diagnosed with osteoporosis between July 2014 and December 2016 were included. The implant group included subjects who had undergone dental implant surgery between January 2017 and December 2017, while the control group included those who had no history of dental implants. The primary outcome was the occurrence of ONJ, and the date of final follow-up was December 2020. RESULTS: A total of 332,728 subjects with osteoporosis were included in the analysis: 83,182 in the implant group and 249,546 in the control group. The risk of ONJ among those who had undergone implant surgery (risk of implant surgery-associated ONJ) was not higher than that among those without implant surgery. The risk of ONJ among those with implants (risk of implant presence-associated ONJ) was lower than that among those without implants. Even in subjects with a history of bisphosphonates, steroids, periodontitis, or tooth extraction, those who had undergone implant surgery or had implants did not have a higher ONJ risk than those who had not undergone surgery or did not have implants; rather, they showed a lower risk. CONCLUSIONS: The results may suggest that dental implants are not associated with an increased risk of ONJ. A further study on whether dental implants are associated with lower ONJ risk is needed. CLINICAL RELEVANCE: Dental implants did not increase the risk of ONJ development in osteoporotic patients, even with a history of bisphosphonates. This may suggest that the risk profiles for ONJ occurrence between selective insertion of dental implants and other dentoalveolar surgery associated with infectious conditions are different.

Effect of dental screening on cardiovascular risk: A nationwide cohort study.

AIM: To evaluate the effect of dental screening on the risk of cardiovascular disease (CVD) using data from a nationwide population-based cohort. MATERIALS AND METHODS: This retrospective cohort study extracted data of 478,245 individuals aged 40-79 years who participated in a health screening programme during 2002-2003 from the National Health Insurance Service-National Health Screening Cohort. Based on screening experience, participants were classified into the non-screening, general screening only, and dental screening groups. Using Cox proportional hazard models, hazard ratios (HRs) were determined for major adverse cardiovascular events (MACE) during each group's 11-year follow-up period. RESULTS: The risk of MACE in the dental screening group was 10% lower than that in the non-screening group (adjusted HR, 0.90; 95% confidence interval [CI], 0.87-0.93; p < .001) and 9% lower than that in the general screening only group (adjusted HR, 0.91; 95% CI, 0.89-0.94; p < .001). CONCLUSIONS: Dental screening was associated with a lower MACE risk; however, decreases in CVD-related healthcare utilization and costs were not clinically significant. The association could be attributed to healthy habits of participants in the dental screening group; nevertheless, it is conceivable that the improvement of oral health through dental screening influenced CVD prevention.

Prediction value of the LACE index to identify older adults at high risk for all-cause mortality in South Korea: a nationwide population-based study.

BACKGROUND: As a tool to predict early hospital readmission, little is known about the association between LACE index and all-cause mortality in older adults. We aimed to validate the LACE index to predict all-cause mortality in older adults and also analyzed the LACE index outcome of all-cause mortality depending on the disease and age of the participants. METHODS: We used the National Health Insurance Service (NHIS) cohort, a nationwide claims database of Koreans. We enrolled 7491 patients who were hospitalized at least once between 2003 and 2004, aged ≥65 years as of the year of discharge, and subsequently followed-up until 2015. We estimated the LACE index using the NHI database. The Cox proportional hazards model was used to estimate the hazard ratio (HR) for all-cause mortality. Furthermore, we investigated all-cause mortality according to age and underlying disease when the LACE index was ≥10 and < 10, respectively. RESULTS: In populations over 65 years of age, patients with LACE index ≥10 had significantly higher risks of all-cause mortality than in those with LACE index < 10. (HR, 1.44; 95% confidence interval, 1.35-1.54). For those patients aged 65-74 years, the HR of all-cause mortality was found to be higher in patients with LACE index≥10 than in those with LACE index < 10 in almost all the diseases except CRF and mental illnesses. And those patients aged ≥75 years, the HR of all- cause mortality was found to be higher in patients with LACE index ≥10 than in those with LACE index < 10 in the diseases of pneumonia and MACE. CONCLUSION: This is the first study to validate the predictive power of the LACE index to identify older adults at high risk for all-cause mortality using nationwide cohort data. Our findings have policy implications for selecting or managing patients who need post-discharge management.

Worsening of health disparities across COVID-19 pandemic stages in Korea.

OBJECTIVES: With the end of the coronavirus disease 2019 (COVID-19) pandemic, the health outcomes of this disease in Korea must be examined. We aimed to investigate health outcomes and disparities linked to socioeconomic status during the COVID-19 pandemic in Korea and to identify risk factors for hospitalization and mortality. METHODS: This nationwide retrospective study incorporated an analysis of individuals with and without COVID-19 in Korea between January 1, 2020 and December 31, 2022. The study period was divided into 4 stages. Prevalence, hospitalization, mortality, and case-fatality rates were calculated per 100,000 population. Multivariate logistic regression was performed to identify risk factors for COVID-19 hospitalization and mortality. RESULTS: Overall, the incidence rate was 40,601 per 100,000 population, the mortality rate was 105 per 100,000 population, and the case-fatality rate was 259 per 100,000 cases. A total of 12,577,367 new cases (24.5%) were recorded in stage 3 and 8,979,635 cases (17.5%) in stage 4. Medical Aid recipients displayed the lowest 3-year cumulative incidence rate (32,737 per 100,000) but the highest hospitalization (5,663 cases per 100,000), mortality (498 per 100,000), and case-fatality (1,521 per 100,000) rates. Male sex, older age, lower economic status, non-metropolitan area of residence, high Charlson comorbidity index, and disability were associated with higher risk of hospitalization and death. Vaccination was found to reduce mortality risk. CONCLUSIONS: As the pandemic progressed, surges were observed in incidence, hospitalization, and mortality, exacerbating disparities associated with economic status and disability. Nevertheless, Korea has maintained a low case-fatality rate across all economic groups.

Effects of the COVID-19 Pandemic on the Medical Use of Elderly Patients with Hypertension: A Nationwide Cohort Study in Korea.

Background: The coronavirus disease 2019 (COVID-19) pandemic has disrupted healthcare services, including chronic disease management, for vulnerable groups, such as older individuals with hypertension. This study aimed to evaluate hypertension management in South Korea's elderly population during the pandemic using treatment consistency indices such as the continuity of care (COC), modified, modified continuity index (MMCI), and most frequent provider continuity (MFPC). Methods: This study used the Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service cohort (K-COV-N cohort) from the National Health Insurance Service between 2017 and 2021. The research included a total of 4,097,299 hypertensive patients aged 65 years or older. We defined 2018 and 2019 as the baseline period before the COVID-19 pandemic and 2020 and 2021 as the COVID-19 period and calculated the indices of medical continuity (number of visits, COC, MMCI, and MFPC) on a yearly basis. Results: The number of visits decreased during the COVID-19 period compared to the baseline period (59.64±52.75 vs. 50.49±50.33, P<0.001). However, COC, MMCI, and MFPC were not decreased in the baseline period compared to the COVID-19 period (0.71±0.21 vs. 0.71±0.22, P<0.001; 0.97±0.05 vs. 0.96±0.05, P<0.001; 0.8±0.17 vs. 0.8±0.17, P<0.001, respectively). Conclusion: COVID-19 had no significant impact on the continuity of care but affected the frequency of outpatient visits for older patients with hypertension. However, this study highlights the importance of addressing healthcare inequalities, especially in older patients with hypertension, during pandemics and advocates for policy changes to ensure continued care for vulnerable populations.

Prevalence and severity of COVID-19 among children and adolescents with autism spectrum disorders in the Republic of Korea.

LAY ABSTRACT: It is more difficult to prevent coronavirus disease 2019 in children and adolescents with autism spectrum disorder, as they have trouble communicating and adjusting to their new daily lives like wearing masks and social distancing. However, there have not been many studies that focused on coronavirus disease 2019 among children and adolescents with autism spectrum disorder. We included all Korean citizens under the age of 19 as our study subjects. Among them, we found out the prevalence, severity, and case fatality of coronavirus disease 2019 in children and adolescents with and without autism spectrum disorder. The prevalence of coronavirus disease 2019 among children and adolescents with autism spectrum disorder was lower than that of those without autism spectrum disorder. For severity, children and adolescents with autism spectrum disorder were more likely to enter severe stages of disease and had higher hospitalization rates than those without autism spectrum disorder. There were no deaths among children and adolescents with autism spectrum disorder, while a few died among children and adolescents without autism spectrum disorder. However, due to the small number of deaths, it was difficult to determine whether there was a link between autism spectrum disorder and coronavirus disease 2019 deaths. We found that the appropriate quarantine policies have played a great role in sustaining overall low prevalence and higher hospitalization rates among children and adolescents with autism spectrum disorder than those without autism spectrum disorder. Furthermore, because Korea has fewer schools and facilities (i.e. personal care, social training, and skilled nursing facility) for children and adolescents with autism spectrum disorder than other countries, those with autism spectrum disorder have fewer social contacts than even before the COVID-19 pandemic.

Association between smoking status and handgrip strength in Korean male adults: based on Korea National Health and Nutrition Examination Survey 2016-2019.

Background: Smoking is a well-known risk factor of frailty. Handgrip strength (HGS) is highly representative of muscular strength and is used in the diagnosis of frailty; however, the relationship between smoking and HGS is not clear. We evaluated the relationship between smoking status and HGS. Objectives: This study aimed to evaluate the association between HGS and smoking status. Methods: We enrolled adult males between the ages of 19 and 80 years who participated in the Korea National Health and Nutrition Examination Survey VII-VIII. A chi-square test and ANOVA were performed to compare the mean handgrip strength (mean HGS) between non-smokers, ex-smokers, and current smokers. Logistic regression analysis was performed to determine the association between the smoking status and mean HGS, and additional analyses were performed by dividing subgroups by age. Results: A total of 7,649 participants were analyzed. When the mean HGS and mean dominant HGS were compared according to smoking status, HGS was higher in the right hand (value of p = 0.03) and left hand (value of p < 0.001) in the order of current smokers, ex-smokers, and non-smokers. Comparing HGS of stronger hands, the mean HGS ex-smokers [aOR, (95% confidence interval): 0.61 (0.46-0.82)] and current smokers: 0.55 (0.38-0.78) was higher than that of non-smokers. When subgroup analysis was performed according to age, current smokers aged >60 years had a higher grip strength than non-smokers. Conclusion: Current smokers had a stronger mean HGS than that of ex-smokers and non-smokers. Current smokers older than 60 years appeared to have a stronger mean HGS than ex-smokers and non-smokers of the same age group.

Association between periodontal disease, tooth extraction, and medication-related osteonecrosis of the jaw in women receiving bisphosphonates: A national cohort-based study.

BACKGROUND: We investigated whether periodontal diseases contribute to the development of medication-related osteonecrosis of the jaw (MRONJ) in addition to tooth extraction, which is a major risk factor for MRONJ occurrence. METHODS: This retrospective, nationwide cohort study was performed using South Korea's National Health Insurance Service database on women aged > 50 years who took bisphosphonates for at least 1 year between 2010 and 2015. MRONJ, periodontal disease, and tooth extraction were defined using the claims data. RESULTS: Among the 27,168 patients analyzed, the incidence of confirmed MRONJ was significantly higher in the periodontal disease group (0.58%) than in the nonperiodontal disease group (0.31%). While extraction alone showed an increased risk of MRONJ development (hazard ratio [HR] = 1.61, 95% confidence interval [CI]: 0.74-3.52), periodontal disease without tooth extraction also indicated a similar risk (HR = 1.68, 95% CI: 0.86-3.28); when a history of both periodontal disease and tooth extraction was present, the HR significantly increased to 2.55 (95% CI: 1.41-4.64). CONCLUSIONS: The risk of MRONJ increased significantly when tooth extraction was performed in patients diagnosed with periodontal disease; therefore, periodontal diseases should be proactively managed in patients taking bisphosphonates.

The Risk Factors of COVID-19 Infection and Mortality among Older Adults in South Korea.

BACKGROUND: This study aimed to identify the risk factors associated with coronavirus disease 2019 (COVID-19) infection and mortality among older adults in South Korea. METHODS: Using Korean National Health Insurance data from January 1, 2020, to March 31, 2022, we analyzed the impact of various factors, including age, comorbidity burden, and insurance type, on COVID-19 infection and mortality rates. RESULTS: Age was the most significant risk factor for mortality in older adults. A higher comorbidity burden was also associated with increased infection (odds ratio [OR]=1.33 for Charlson Comorbidity Index [CCI] ≥2, 95% confidence interval [CI] 1.321-1.339) and mortality (OR=1.537 for CCI ≥2, 95% CI 1.459-1.618) rates. While Medical Aid recipients exhibited lower infection rates (OR=0.898, 95% CI 0.89-0.906) than National Health Insurance beneficiaries, they had higher mortality rates (OR=1.692, 95% CI 1.623-1.763). CONCLUSION: These results emphasized the need to prioritize vaccination and allocate healthcare resources for older adults, particularly those with multiple comorbidities. Addressing socioeconomic disparities and ensuring equitable access to testing and healthcare services are crucial for mitigating the impact of COVID-19 on older adults.

COVID-19 vaccination, incidence, and mortality rates among individuals with mental disorders in South Korea: A nationwide retrospective study.

We examined COVID-19 vaccination, incidence, and mortality rates among patients with mental health disorders in South Korea from 1 January 2020 to 31 December 2021. The study found that individuals with mental disorders had higher COVID-19 incidence and mortality than those without. Patients with mood disorders had higher vaccination rates and COVID-19 incidence and mortality than those without mental disorders. In contrast, patients with schizophrenia had lower vaccination rates, slightly lower COVID-19 incidence, and higher COVID-19 mortality. Patients with mental health disorders have been vulnerable to COVID-19, and more attention should be paid to their vaccination and health needs.

Pulp and periapical disease as a risk factor for osteonecrosis of the jaw: a national cohort-based study in Korea.

PURPOSE: This longitudinal cohort study aimed to evaluate the relationship between osteonecrosis of the jaw and pulp and periapical disease in patients who were administered bisphosphonates. METHODS: Using data from a nationwide cohort, we examined the association among dental caries, pulp and periapical disease, and osteonecrosis of the jaw in women aged >50 years who received bisphosphonates for more than 1 year between 2002 and 2015. Because of ambiguities in the diagnosis of osteonecrosis of the jaw in population-based data, we operationally defined and categorized the condition into established and potential osteonecrosis of the jaw. RESULTS: Pulp and periapical disease significantly increased the development of both established and potential osteonecrosis of the jaw (hazard ratio, 2.21; 95% confidence interval, 1.40-3.48; and hazard ratio, 2.22; 95% confidence interval, 1.65-2.98, respectively). Root canal treatment did not have any influence on the development of osteonecrosis of the jaw. CONCLUSIONS: Pulp and periapical disease may be a major risk factor for osteonecrosis of the jaw. The study findings suggest that patients should undergo regular dental examinations to detect pulp and periapical disease before or during the administration of bisphosphonates and that root canal treatment should be considered to decrease the risk of osteonecrosis of the jaw.

Effect of National Oral Health Screening Program on the Risk of Head and Neck Cancer: A Korean National Population-Based Study.

PURPOSE: Poor oral health is associated with head and neck cancer (HNC). We evaluated whether a national oral health screening program (OHSP) could reduce the risk of HNC. MATERIALS AND METHODS: Data from 408,247 healthy individuals aged ≥ 40 years from the National Health Insurance System-National Health Screening program during 2003 and 2004 in Korea were analyzed. The risk of HNC was compared between subjects who underwent OHSP (HEALS-Dental+, n=165,292) and routine health check-ups only (HEALS-Dental‒, n=242,955). The impact of individual oral health-related factors on HNC risk was evaluated in HEALS-Dental+. RESULTS: A total of 1,650 HNC cases were diagnosed. The 10-year HNC-free rate was 99.684% with a median follow-up of 11 years. The risk of all HNC (hazard ratio [HR], 1.16; 95% confidence interval [CI], 1.03 to 1.29; p=0.011) and oropharyngeal cancer (HR, 1.48; 95% CI, 1.13 to 1.94; p=0.005) was significantly higher in HEALS-Dental‒ than in HEALS-Dental+. In HEALS-Dental+, oral cavity cancer was marginally reduced (p=0.085), and missing teeth was a significant factor for HNC (HR, 1.24; 95% CI, 1.02 to 1.50; p=0.032). Toothbrushing was a significant factor in univariate analysis (p=0.028), but not in multivariate analysis (p=0.877). CONCLUSION: The National OHSP significantly reduced the long-term HNC risk, particularly the incidence of oropharyngeal cancer. Routine OHSP should be considered at the population level.

Power of universal health coverage in the era of COVID-19: A nationwide observational study.

BACKGROUND: During the COVID-19 pandemic, South Korea has achieved perfect universal health coverage (UHC)-all Koreans receive UHC regardless of their socioeconomic status. The current study investigated whether socioeconomic disparities remained in COVID-19 health outcomes under UHC. METHODS: This retrospective, observational study included all 7,590 confirmed COVID-19 patients in South Korea up to 15 May 2020. We used the official medical claim database, and socioeconomic status was estimated by insurance type (National Health Insurance Service [NHIS] beneficiaries and Medical Aid [MA] recipients). Type of insurance is a well-known indicator of socioeconomic status. Prevalence (per one million), mortality rate (per one million), and case fatality rate were calculated. To determine the factors associated with case fatality rate, multivariable logistic regressions were performed. FINDINGS: The nationwide prevalence, mortality rate, and case fatality rate of COVID-19 was 144•4, 4•3 and 3•0%, respectively. MA recipients had higher prevalence (424•3 vs 136.3), mortality rate (28•3 vs 3•6), and case fatality rate (6•7 vs 2•7) than NHIS beneficiaries. However, the adjusted analysis showed that the type of insurance was not associated with higher odds of case fatality. INTERPRETATION: We found socioeconomic disparities in COVID-19 prevalence and fatality despite UHC. However, disparities in fatality were not due to socioeconomic status, but due to the poor underlying health conditions of the people. This result can be explained by a combination of UHC, rapid early testing and treatment, transmission-reducing behaviours, and regional preparedness. FUNDING: This research did not receive any funding.

Gradual, but Not Sudden, Dose-Dependent Increase of ONJ Risk With Bisphosphonate Exposure: A Nationwide Cohort Study in Women With Osteoporosis.

Background: A causal relationship of bisphosphonate (BP) exposure with osteonecrosis of the jaw (ONJ) has been reported; however, a definite dose-dependent risk remains to be elucidated beyond current vague recommendations of 4-year oral BP for ONJ risk increase. Objective: To identify the effect of bisphosphonate cumulative dose on ONJ development in women with osteoporosis. Methods: A retrospective cohort study was designed using the National Health Insurance Service-National Health Screening database of Korea. Females over the age of 50 were diagnosed with osteoporosis based on the International Classification of Diseases 10th revision (ICD-10) codes (M80, M81, and M82) with bisphosphonate prescriptions. The cumulative dose of bisphosphonate was calculated using defined daily doses (DDD) to provide an accurate BP cumulative effect on ONJ occurrence. Osteonecrosis of the jaw was identified using both ICD-10 codes and related procedure codes. The incidence rates of ONJ and hazard ratios were estimated according to the bisphosphonate cumulative dose. Results: Among 74,491 included subjects, 190 cases of ONJ were identified. The incidence rate substantially increased after BP cumulative dose over 1 year (25.75 for DDD < 365, which increased to 53.43 for 365 ≤ DDD < 730). Compared to subjects with a cumulative dose of DDD < 365, subjects with a cumulative dose of 365 ≤ DDD < 730 had 2.36-fold hazard for developing ONJ (p < 0.001). Conclusion: A bisphosphonate cumulative dose of more than 1 year had an increased risk of ONJ development. A gradual, but not sudden, dose-dependent increase in ONJ risk with BP exposure needs to be considered in providing the optimal BP treatment duration.