Validation of the Patient Health Questionnaire-9 for Screening Depressive Disorders among Korean Employees: A Longitudinal Study of the National Health Examination Data.

This nationwide longitudinal study examined the screening utility of the Patient Health Questionnaire-9 (PHQ-9) for Korean workers (aged 20, 30, 40, 50, 60, and 70 years) who completed the questionnaire in 2018. Data on disease names and health-related behaviors were collected from the National Health Insurance Service (NHIS). Follow-up began on 1 January 2018, and the primary endpoint was the hospitalization date for depression, self-harm, or suicide or 31 December 2019. Of the 766,351 participants, 741,423 received depression screening. Those screened were classified into normal (n = 716,760) and high-risk groups (n = 24,663) based on PHQ-9 scores. The incidence of hospital admissions for depression, self-harm, or suicide in the non-screened, normal, and high-risk groups was analyzed, and the PHQ-9's validity was examined. There were more females in the high-risk group than in the normal group, and the income distribution differed. The two-year cumulative incidence was highest for the high-risk group (4.21%), followed by the normal (0.89%) and non-screened groups (0.80%). The PHQ-9's sensitivity was low (males: 14.2%; females: 13.8%). Its specificity for males and females was 97.1% and 96.3%, respectively. Our findings may help develop a system to prevent suicides and hospitalizations attributed to workplace depression.

Pregnancy loss and Income in the Republic of Korea using National Health Insurance Service Data, 2008-2014.

BACKGROUND: Although unintentional pregnancy loss is common, national representative statistics are lacking in high-income East Asian countries undergoing rapid demographic changes. It is necessary to confirm the income inequality of pregnancy loss even in universal national health insurance. METHOD: Using National Health Insurance Service data between 2008 and 2014, the annual prevalence of pregnancy loss was enumerated, and differences in pregnancy loss according to age and income levels were assessed by multivariable Poisson regression. Joint-point regression was used to examine the trend of pregnancy loss. RESULT: On average, there was a 15.0% annual pregnancy loss among 3,941,020 pregnancy cases from 2008 to 2014. Pregnancy loss inequality increased stepwise with income levels except for the highest income group. After adjusting for income levels, the annual percent change of age-standardized prevalence significantly increased by 2.6% every year since 2011. CONCLUSION: Even in high-income countries with universal national health insurance, income inequality in pregnancy loss is observed. Further appraisal is needed to explain the increasing trend of pregnancy loss between 2011 and 2014 even after adjusting income.

Long work hours and decreased glomerular filtration rate in the Korean working population.

OBJECTIVES: We studied the association between long working hours and decreased kidney function, which was determined using estimated glomerular filtration rate (eGFR), among the working population in South Korea. METHODS: We analysed nationally representative cross-sectional data for 20 851 Korean workers ≥20 years of age. A negative binomial regression model was used to test differences in the prevalence of chronic kidney disease (eGFR <60 mL/min/1.73 m2) among workers divided into groups according to weekly working hours (<30, 30-40, 41-51 and ≥52 hours/week). Multivariate linear regression analysis was performed to investigate the association between weekly working hours and eGFR, with adjustments made for age, sex/gender, income, education, shift work, occupation, smoking, alcohol use, hypertension, diabetes mellitus, body mass index, systolic blood pressure, fasting blood glucose and total serum cholesterol. RESULTS: A 1-hour increase in weekly working hours was associated with 0.057 mL/min/1.73 m2 (95% CI 0.005 to 0.109) decrease in eGFR among participants who worked ≥52 hours/week. Among participants without hypertension or diabetes, a 1-hour increase in weekly working hours was significantly associated with 0.248 and 0.209 mL/min/1.73 m2 decrease in eGFR among participants who worked 30-40 hours/week and 41-51 hours/week, respectively. CONCLUSION: Long working hours are associated with decreased kidney function. We expect that our findings could call for more research regarding this association and provide policy-oriented perspectives.

Epidemiology of ALS in Korea using nationwide big data.

OBJECTIVE: This study aimed to determine the incidence, prevalence and survival time of Korean patients with amyotrophic lateral sclerosis (ALS) using National Health Insurance Service (NHIS) data. METHODS: Using NHIS data, the Korean nationwide health dataset, we identified patients with motor neuron diseases who were first diagnosed with a KCD-6 code (G12.20-G12.28; modified from ICD-10 codes) between 2011 and 2015. ALS (G12.21 code) epidemiological characteristics, including annual incidence, prevalence, mortality rates and survival time, were analysed and compared with sociodemographic variables. RESULTS: New patients with ALS (n=3049) were enrolled over 5 years. The mean annual incidence was 1.20/100 000, and the sex ratio was 1.60 (male:female). The mean age at the time of diagnosis was 61.4 years. The prevalence rate was 3.43/100 000 in 2015. In this period, riluzole was prescribed to 53.6% of patients with ALS. Furthermore, 20.3% of patients with ALS underwent tracheostomy. When analysed for age and socioeconomic status, ALS prevalence rate was 10.71 in the aged group (≥60) in 2015 and was lowest in the middle-income group compared with that in the high-income and low-income groups. The estimated mean survival time in this population was 50.0 months, and the 3-year and 5-year mortality rates were 52.1% and 63.7%, respectively. CONCLUSIONS: This study is the first nationwide survey for epidemiological characteristics of ALS in Korea using national data. The use of these data substantially advances the understanding of Korean and Asian ALS epidemiology and its relationship with socioeconomic status, age and sex.