Incidence of Subacute Thyroiditis During the COVID-19 Pandemic in South Korea Using the National Health Insurance Service Database.

Background: Subacute thyroiditis (SAT) is a thyroid disease initiated by viral infection. Whether severe acute respiratory syndrome coronavirus 2 infection can cause SAT is unclear. This study investigated changes in the nationwide incidence of SAT during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This is a retrospective, cross-sectional population-based study. Data regarding SAT and related viral diseases, including COVID-19, from 2017 to 2020 were collected from the National Health Insurance Service and Korea Disease Control and Prevention Agency databases. Results: In a total of 15,447 patients, 2484 men and 12,963 women diagnosed with SAT from 2017 to 2020 were included in this study. The incidence of SAT was significantly higher in 2020 than in 2017-2019 (8.30 vs. 7.27 per 100,000 persons, p < 0.001), while the incidence of SAT-related respiratory viral diseases, except for COVID-19, markedly decreased in 2020. The peak age of SAT incidence in 2020 was 50-59 years, and the women-to-men ratio was 5.4 (similar to that in 2017-2019). Corticosteroids were prescribed more often (72% vs. 58%, p < 0.001), and the prescription rate exceeding 1 month was significantly higher (45% vs. 40%, p < 0.01) in 2020 than in 2017-2019. Conclusions: The incidence of SAT increased in 2020 in association with COVID-19. A diagnostic approach to COVID-19 needs to be considered in patients with SAT during the COVID-19 pandemic.

Effects of living in the same region as one's workplace on the total fertility rate of working women in Korea.

OBJECTIVES: The lowest-low fertility status of Korea has continued for the past 17 years despite governmental efforts to encourage childbirth. As the number of working women has increased, their residence patterns have changed; however, the impact of this factor has yet to be explored. Therefore, this study was conducted to investigate the effects of residence patterns relative to the workplace on the total fertility rate of working women. METHODS: Information on eligibility and healthcare utilization was obtained from the National Health Information Database between 2011 and 2015. The study participants were working women aged 15-49 years. We classified their residence relative to their workplace into 3 patterns: same municipality, same province, and different province. The total fertility rate was calculated and logistic regression was performed of childbirth according to residence pattern, adjusting for age, insurance contribution quartile, size of the workplace, year of birth, and province of residence. RESULTS: The total fertility rates of working women from 2011 to 2015 were 1.091, 1.139, 1.048, 1.073, and 1.103, respectively. The total fertility rate by residence pattern was highest in women residing in the same municipality as their workplace. After adjustment, the odds of childbirth in women from the same municipality and the same province were 21.6% and 16.0% higher than those of women residing in a different province, respectively. CONCLUSIONS: The total fertility rate was higher among women living near their workplace. Therefore, effective policy measures should be taken to promote the proximity of working women's workplace and residence.

Interactions of Behavioral Changes in Smoking, High-risk Drinking, and Weight Gain in a Population of 7.2 Million in Korea.

OBJECTIVES: To identify simultaneous behavioral changes in alcohol consumption, smoking, and weight using a fixed-effect model and to characterize their associations with disease status. METHODS: This study included 7 000 529 individuals who participated in the national biennial health-screening program every 2 years from 2009 to 2016 and were aged 40 or more. We reconstructed the data into an individual-level panel dataset with 4 waves. We used a fixed-effect model for smoking, heavy alcohol drinking, and overweight. The independent variables were sex, age, lifestyle factors, insurance contribution, employment status, and disease status. RESULTS: Becoming a high-risk drinker and losing weight were associated with initiation or resumption of smoking. Initiation or resumption of smoking and weight gain were associated with non-high-risk drinkers becoming high-risk drinkers. Smoking cessation and becoming a high-risk drinker were associated with normal-weight participants becoming overweight. Participants with newly acquired diabetes mellitus, ischemic heart disease, stroke, and cancer tended to stop smoking, discontinue high-risk drinking, and return to a normal weight. CONCLUSIONS: These results obtained using a large-scale population-based database documented interactions among lifestyle factors over time.

Cohort Profile: National health insurance service-senior (NHIS-senior) cohort in Korea.

PURPOSE: The National Health Insurance Service (NHIS)-Senior was set up to provide high-quality longitudinal data that can be used to explore various aspects of changes in the socio-economical and health status of older adults, to predict risk factors and to investigate their health outcomes. PARTICIPANTS: The NHIS-Senior cohort, a Korean nationwide retrospective administrative data cohort, is composed of older adults aged 60 years and over in 2002. It consists of 558 147 people selected by 10% simple random sampling method from a total of 5.5 million subjects aged 60+ in the National Health Information Database. The cohort was followed up through 2015 for all subjects, except for those who were deceased. FINDINGS TO DATE: The healthcare utilisation and admission rates were the highest for acute upper respiratory infections and influenza (75.2%). The age-standardised (defined with reference to the world standard population) mortality rate for 10 years (through 2012) was 4333 per 100 000 person-years. Malignant neoplasms were the most common cause of death in both sexes (1032.1 per 100 000 person-years for men, 376.7 per 100 000 person-years for women). A total of 34 483 individuals applied for long-term care service in 2008, of whom 17.9% were assessed as grade 1, meaning that they were completely dependent on the help of another person to live daily life. FUTURE PLANS: The data are provided for the purposes of policy and academic research under the Act on Promotion of the Provision and Use of Public Data in Korea. The NHIS-Senior cohort data are only available for Korean researchers at the moment, but it is possible for researchers outside the country to gain access to the data by conducting a joint study with a Korean researcher. The cohort will be maintained and continuously updated by the NHIS.

Provider factors influencing prescriptions of recommended antihypertensive medications among patients with diabetes and hypertension
.

OBJECTIVE: Managing hypertension to prevent complications in patients with diabetes requires appropriate pharmacotherapy. This study aimed to analyze healthcare provider factors influencing prescriptions of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) as the first-line therapy in managing hypertension among patients with diabetes in primary care. MATERIALS: This study used National Health Insurance Claims Data in Korea. METHODS: We calculated the prescription rate of angiotensin-converting enzyme inhibitors (ACE inhibitors) or ARBs by dividing the number of patients prescribed an ACE inhibitor or an ARB by the number of patients with diabetes prescribed hypoglycemic agents and antihypertensive agents. We performed a logistic regression to investigate the factors influencing the prescription rate of ACE inhibitors or ARBs. RESULTS: The mean prescription rate of ACE inhibitors or ARBs was 69.8%. The prescription rate of ACE inhibitors or ARBs decreased with increasing physician and patient age. The rate was higher for male patients than for females. The rate was higher in institutions with a greater number of physicians and among internists than among general practitioners, surgery-related and internal medicine-related specialists. The rate was significantly influenced by the mean monthly number of patients with hypertension per medical institution, the number of physicians per medical institution, and the physician's age and specialty. CONCLUSION: The age and specialty of the prescribing physician influenced the use of ACE inhibitors or ARBs in patients with diabetes and hypertension in primary care. Efforts are needed to promote information exchange among physicians and the appropriate prescriptions of antihypertensive agents in patients with diabetes and hypertension in primary care.

Effects of the Relative Distribution of Body Mass Index on the Incidence of Hypertension and Diabetes Mellitus, Using the Korean Obesity Index.

BACKGROUND: The Korean Obesity Index, which contains standard reference data (SRD) of obesity, was established in 2016 and revised in 2017 based on national health screening data to provide the distribution of the body mass index (BMI) of the whole population of Korea as a reference. This study aimed to investigate the effect of the SRD of obesity on the incidence of hypertension (HTN) and diabetes mellitus (DM). METHODS: The percentile of BMI was calculated for each of the 864 subgroups by defined by gender, region, and age group according to the groupings in the SRD. Incident cases were defined as the presence of HTN and DM and medication prescription in the health care utilization database for a given individual in 2017, but not in 2015-2016. Logistic regression for the incidence of HTN and DM according to the relative distribution of BMI was performed. Gender, age, insurance type, insurance contribution, smoking, drinking, physical activity, blood pressure, waist circumference, fasting glucose, triglycerides, high-density lipoprotein cholesterol, the Charlson comorbidity index (2012-2014), and diagnosis and medication for HTN and DM (2015-2017) were adjusted in the analysis. RESULTS: The C-statistics of the fully adjusted model for HTN and DM were 0.799 and 0.852, respectively. The risks of HTN and DM increased by 1.007 and 1.011 times, respectively, for each 1-percentile increase in BMI. CONCLUSION: The results showed that BMI was associated with the incidence of HTN and DM according to the SRD. The relative distribution of BMI can be used to motivate self-care through providing more detailed information to individuals.

Level of Agreement and Factors Associated With Discrepancies Between Nationwide Medical History Questionnaires and Hospital Claims Data.

OBJECTIVES: The objectives of this study were to investigate the agreement between medical history questionnaire data and claims data and to identify the factors that were associated with discrepancies between these data types. METHODS: Data from self-reported questionnaires that assessed an individual's history of hypertension, diabetes mellitus, dyslipidemia, stroke, heart disease, and pulmonary tuberculosis were collected from a general health screening database for 2014. Data for these diseases were collected from a healthcare utilization claims database between 2009 and 2014. Overall agreement, sensitivity, specificity, and kappa values were calculated. Multiple logistic regression analysis was performed to identify factors associated with discrepancies and was adjusted for age, gender, insurance type, insurance contribution, residential area, and comorbidities. RESULTS: Agreement was highest between questionnaire data and claims data based on primary codes up to 1 year before the completion of self-reported questionnaires and was lowest for claims data based on primary and secondary codes up to 5 years before the completion of self-reported questionnaires. When comparing data based on primary codes up to 1 year before the completion of self-reported questionnaires, the overall agreement, sensitivity, specificity, and kappa values ranged from 93.2 to 98.8%, 26.2 to 84.3%, 95.7 to 99.6%, and 0.09 to 0.78, respectively. Agreement was excellent for hypertension and diabetes, fair to good for stroke and heart disease, and poor for pulmonary tuberculosis and dyslipidemia. Women, younger individuals, and employed individuals were most likely to under-report disease. CONCLUSIONS: Detailed patient characteristics that had an impact on information bias were identified through the differing levels of agreement.

Cohort profile: the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) in Korea.

PURPOSE: The National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) is a cohort of participants who participated in health screening programmes provided by the NHIS in the Republic of Korea. The NHIS constructed the NHIS-HEALS cohort database in 2015. The purpose of this cohort is to offer relevant and useful data for health researchers, especially in the field of non-communicable diseases and health risk factors, and policy-maker. PARTICIPANTS: To construct the NHIS-HEALS database, a sample cohort was first selected from the 2002 and 2003 health screening participants, who were aged between 40 and 79 in 2002 and followed up through 2013. This cohort included 514 866 health screening participants who comprised a random selection of 10% of all health screening participants in 2002 and 2003. FINDINGS TO DATE: The age-standardised prevalence of anaemia, diabetes mellitus, hypertension, obesity, hypercholesterolaemia and abnormal urine protein were 9.8%, 8.2%, 35.6%, 2.7%, 14.2% and 2.0%, respectively. The age-standardised mortality rate for the first 2 years (through 2004) was 442.0 per 100 000 person-years, while the rate for 10 years (through 2012) was 865.9 per 100 000 person-years. The most common cause of death was malignant neoplasm in both sexes (364.1 per 100 000 person-years for men, 128.3 per 100 000 person-years for women). FUTURE PLANS: This database can be used to study the risk factors of non-communicable diseases and dental health problems, which are important health issues that have not yet been fully investigated. The cohort will be maintained and continuously updated by the NHIS.