Association between heat and hospital admissions in people with disabilities in South Korea: a nationwide, case-crossover study.

BACKGROUND: Despite extensive findings on the hazardous impacts of environmental heat exposure, little is known about the effect on people with disabilities. This study aimed to estimate the association between environmental heat exposure and emergency department admissions for people with disabilities compared with people without disabilities. METHODS: In this nationwide, case-crossover study, we linked data on emergency department admissions (cases) for any cause in the warm season in South Korea from the Korean National Health Insurance Service (NHIS)-National Sample Cohort database (a nationally representative database of 1 million systematically sampled beneficiaries covering all ages) from Jan 1, 2002, to Dec 31, 2019, and short-term daily mean temperature exposure (measured via Google Earth Engine at a 9 km spatial grid, aggregated to district). We defined beneficiaries with disabilities as those who were registered as disabled in the NHIS; disabilities included in our study were physical disability, brain lesion disorders, blindness or vision loss, and deafness or hearing loss. Other types of disability were not included for confidentiality reasons. A time-stratified case-crossover design, in which participants served as their own control, was used with conditional logistic regression to estimate the association between heat and emergency department admissions in people with and without disabilities. FINDINGS: 23 792 emergency department admissions were recorded for 59 527 people with disabilities. Of these 23 792 admissions, 10 234 (43·0%) individuals were female and 13 558 (57·0%) were male. The odds ratio (OR) of emergency department admissions associated with heat (99th temperature percentile vs 75th percentile) was 1·15 (95% CI 1·07-1·24) in people with disabilities and 1·06 (1·04-1·09) in people without disabilities. The annual excess number of emergency department admissions attributable to heat per 100 000 persons-years was 27·81 admissions (95% CI 9·20-45·69) and excess medical costs were US$638 739·47 (95% CI 201 900·12-1 059 641·87) in people with disabilities; these values were more than four times that of the non-disabled population. People with brain lesion disorders, people with severe physical disabilities, female individuals, and those aged 65 years or older showed higher heat risks. The risks of emergency department admissions due to mental disorder (1·89, 95% CI 1·18-3·00) and respiratory diseases (1·34, 1·06-1·70) also showed higher heat risks than for the other two analysed causes of admission (cardiovascular and genitourinary diseases). INTERPRETATION: Heat was associated with increased risk of emergency department admissions for people with and without disabilities, but the risk appeared to be higher for those with disabilities. These results can inform policy makers when establishing action plans for people with disabilities. FUNDING: National Research Foundation of Korea, the South Korean Ministry of Environment, and the South Korean Ministry of Education.

Timely accessibility to healthcare resources and heatwave-related mortality in 7 major cities of South Korea: a two-stage approach with principal component analysis.

Background: Due to the ongoing effects of climate change, the incidence of heatwave-related mortality is rising globally. Improved allocation and utilization of healthcare resources could help alleviate this issue. This study aimed to identify healthcare resource factors associated with heatwave-related mortality in seven major cities of South Korea. Methods: We analyzed daily time-series data on mean temperature and all-cause mortality from 2011 to 2019. Using principal component analysis (PCA), we clustered district-level healthcare resource indicators into three principal components (PCs). To estimate district-specific heatwave-mortality risk, we used a distributed lag model with a quasi-Poisson distribution. Furthermore, a meta-regression was performed to examine the association between healthcare resources and heatwave-mortality risk. Findings: A total of 310,363 deaths were analyzed in 74 districts. The lag-cumulative heatwave-related mortality (RRs) ranged from 1.12 (95% confidence interval [CI]: 1.07, 1.17) to 1.21 (95% CI 1.05, 1.38), depending on the definitions used for heatwaves. Of the three PCs for healthcare resources (PC1: pre-hospital emergency medical service, PC2: hospital resources, PC3: timely access), timely access was associated with reduced risk of heatwave-related mortality, particularly among the elderly. Specifically, timely access to any emergency room (ER) exhibited the strongest association with lower heatwave-related mortality. Interpretation: Our findings suggest that timely access to any ER is more effective in reducing heatwave-related mortality risk than access to higher-level healthcare facilities, especially among the elderly. Therefore, healthcare resource factors and ER accessibility should be prioritized when identifying vulnerable populations for heatwaves, along with known individual and socio-demographic factors. Funding: This work was supported by the Research Program funded by the Korea Disease Control and Prevention Agency (2022-12-303), the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2022R1A2C2092353) and the MD-PhD/Medical Scientist Training Program through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea.

Particulate matters (PM2.5, PM10) and the risk of depression among middle-aged and older population: analysis of the Korean Longitudinal Study of Aging (KLoSA), 2016-2020 in South Korea.

BACKGROUND: There is a growing concern that particulate matter (PM) such as PM2.5 and PM10 has contributed to exacerbating psychological disorders, particularly depression. However, little is known about the roles of these air pollutants on depression in elderly. Therefore, this study aimed to examine the association between PM2.5 and PM10, and depression in the elderly population in South Korea. METHODS: We used panel survey data, the Korean Longitudinal Study of Aging (KLoSA), administered by the Labor Institute during the study period of 2016, 2018, and 2020 covering 217 districts in South Korea (n = 7674). Annual district-specific PM2.5 and PM10 concentrations were calculated for the study period from the monthly prediction concentrations produced by a machine-learning-based ensemble model (cross-validated R2: 0.87), then linked to the people matching with year and their residential district. We constructed a generalized estimating equation (GEE) model with a logit link to identify the associations between each of the long-term PM2.5 and PM10 exposures and depression (CES-D 10) after adjusting for individual and regional factors as confounders. RESULTS: In single-pollutant models, we found that long-term 10 [Formula: see text] increments in PM2.5 (OR 1.36, 95% CI 1.20-1.56) and PM10 (OR 1.19, 95% CI 1.10-1.29) were associated with an increased risk of depression in the elderly. Associations were consistent after adjusting for other air pollutants (NO2 and O3) in two-pollutant models. In addition, the impacts substantially differed by regions grouped by the tertile of the population density, for which the risks of particulate matters on depression were substantial in the middle- or high-population-density areas in contrast to the low-population-density areas. CONCLUSIONS: Long-term exposure to PM2.5 and PM10 was associated with a higher risk of developing depression in elderly people. The impact was modified by the population density level of the region where they reside.

Fluctuating risk of acute kidney injury-related mortality for four weeks after exposure to air pollution: A multi-country time-series study in 6 countries.

BACKGROUND: Recent studies have reported that air pollution is related to kidney diseases. However, the global evidence on the risk of death from acute kidney injury (AKI) owing to air pollution is limited. Therefore, we investigated the association between short-term exposure to air pollution-particulate matter ≤ 2.5 µm (PM2.5), ozone (O3), and nitrogen dioxide (NO2)-and AKI-related mortality using a multi-country dataset. METHODS: This study included 41,379 AKI-related deaths in 136 locations in six countries during 1987-2018. A novel case time-series design was applied to each air pollutant during 0-28 lag days to estimate the association between air pollution and AKI-related deaths. Moreover, we calculated AKI deaths attributable to non-compliance with the World Health Organization (WHO) air quality guidelines. RESULTS: The relative risks (95% confidence interval) of AKI-related deaths are 1.052 (1.003, 1.103), 1.022 (0.994, 1.050), and 1.022 (0.982, 1.063) for 5, 10, and 10 µg/m3 increase in lag 0-28 days of PM2.5, warm-season O3, and NO2, respectively. The lag-distributed association showed that the risk appeared immediately on the day of exposure to air pollution, gradually decreased, and then increased again reaching the peak approximately 20 days after exposure to PM2.5 and O3. We also found that 1.9%, 6.3%, and 5.2% of AKI deaths were attributed to PM2.5, warm-season O3, and NO2 concentrations above the WHO guidelines. CONCLUSIONS: This study provides evidence that public health policies to reduce air pollution may alleviate the burden of death from AKI and suggests the need to investigate the several pathways between air pollution and AKI death.

Beneficial impacts of residential greenness on sleep deprivation in adults aged 19 or older living in South Korea: A nationwide community health survey in 2011-2018.

BACKGROUND: Evidence of the relationship between greenness and sleep is limited, and, given the worsening sleep insufficiency worldwide, this relationship needs elucidation. In this study, we investigated the association of greenness with sleep deprivation using nationwide survey data. METHODS: This study included 1,727,273 participants in the Korea Community Health Survey who resided in all 229 districts of South Korea from 2011 to 2018. Sleep deprivation variables were defined as strong deprivation or mild deprivation, based on average daily sleep duration of <5 or 5-6 h, respectively. District-specific annual average of satellite-derived enhanced vegetation index (EVI) was used as a green space exposure. A logistic regression with complex survey weights was used to estimate the association between greenness and sleep deprivation, and it was further examined by sex, age group, educational status, income level, and population density. The regression analysis was performed annually, and the annual estimates were pooled by a combined data analysis. RESULTS: A higher level of greenness was associated (odds ratio [95 % confidence interval]) with strong and mild sleep deprivation (0.96 [0.93-0.99] and 0.96 [0.95-0.97]), respectively, and males and the younger age group (<65 years) showed a more prominent association with greenness than in females and the elderly group (65 years or older). In addition, only high-population-density areas showed evident associations of greenness with both strong and mild sleep deprivation. CONCLUSIONS: This large population-based study provides important epidemiological evidence for improving sleep quantity through an increase in greenness exposure and supports policymakers in establishing strategies for urban planning.

Association of long-term exposure to air pollution with chronic sleep deprivation in South Korea: A community-level longitudinal study, 2008-2018.

BACKGROUND AND OBJECTIVE: Although there are many findings about the effects of fine particulate matter (PM2.5) and sleep deprivation on health respectively, the association between PM2.5 and chronic sleep deprivation has rarely been investigated. Thus, we aimed to investigate this association using a nationwide survey in South Korea. METHOD: We examined the association between long-term exposure to PM2.5 and chronic sleep deprivation using a national cross-sectional health survey covering the entire 226 districts in inland South Korea from 2008 to 2018, with a machine learning-based national air pollution prediction model with 1 km2 spatial resolution. RESULTS: Chronic sleep deprivation was positively associated with PM2.5 in the total population (odds ratio (OR): 1.09, 95% confidence interval (CI): 1.05-1.13) and sub-population (low, middle, high population density areas with OR: 1.127, 1.09, and 1.059, respectively). The association was consistently observed in both sexes (males with OR: 1.09, females with OR: 1.09)) and was more pronounced in the elderly population (OR: 1.12) than in the middle-aged (OR: 1.07) and young (OR: 1.09) populations. CONCLUSIONS: Our results are consistent with the hypothesis regarding the relationship between long-term PM2.5 exposure and chronic sleep deprivation, and the study provides quantitative evidence for public health interventions to improve air quality that can affect chronic sleep conditions.

Excess mortality and the COVID-19 pandemic: causes of death and social inequalities.

BACKGROUND: During the coronavirus diseases 2019 (COVID-19) pandemic, population's mortality has been affected not only by the risk of infection itself, but also through deferred care for other causes and changes in lifestyle. This study aims to investigate excess mortality by cause of death and socio-demographic context during the COVID-19 pandemic in South Korea.  METHODS: Mortality data within the period 2015-2020 were obtained from Statistics Korea, and deaths from COVID-19 were excluded. We estimated 2020 daily excess deaths for all causes, the eight leading causes of death, and according to individual characteristics, using a two-stage interrupted time series design accounting for temporal trends and variations in other risk factors. RESULTS: During the pandemic period (February 18 to December 31, 2020), an estimated 663 (95% empirical confidence interval [eCI]: -2356-3584) excess deaths occurred in South Korea. Mortality related to respiratory diseases decreased by 4371 (3452-5480), whereas deaths due to metabolic diseases and ill-defined causes increased by 808 (456-1080) and 2756 (2021-3378), respectively. The increase in all-cause deaths was prominent in those aged 65-79 years (941, 88-1795), with an elementary school education or below (1757, 371-3030), or who were single (785, 384-1174), while a decrease in deaths was pronounced in those with a college-level or higher educational attainment (1471, 589-2328). CONCLUSION: No evidence of a substantial increase in all-cause mortality was found during the 2020 pandemic period in South Korea, as a result of a large decrease in deaths related to respiratory diseases that offset increased mortality from metabolic disease and diseases of ill-defined cause. The COVID-19 pandemic has disproportionately affected those of lower socioeconomic status and has exacerbated inequalities in mortality.

Excess suicide attributable to the COVID-19 pandemic and social disparities in South Korea.

The impact of COVID-19 pandemic on suicide remains unclear and might differ according to individuals' socioeconomic characteristics. We aimed to investigate excess suicide attributable to COVID-19 in South Korea, stratified by the outbreak period and individual characteristics. We obtained daily time-series suicide mortality data for January 2017-December 2020 from the Korea National Statistics Office and performed a two-stage interrupted time-series analysis. We estimated excess suicide in 16 regions of Korea using a quasi-Poisson time-series regression model and pooled the region-specific estimates using a mixed-effects multivariate meta-analysis model in the first and second stages, respectively. From February 18 to December 31, 2020, suicide decreased by 9.5% [95% empirical confidence interval (eCI): 3.8%, 15.6%] compared to the number expected from the pre-pandemic period. The decrease in excess suicide risk from the initial pandemic was pronounced during the pandemic's first and third waves. Further, we found that the decrease in suicide was more evident in individuals who were male [11.7% (95% eCI: 5.5%, 18.0%)], middle-aged [13.7% (95% eCI: 7.8%, 19.6%)], highly educated [12.6% (95% eCI: 6.4%, 19.4%)], and married [13.6% (95% eCI: 8.0%, 20.3%)] than in the general population, based on the point estimates. Our results provide timely evidence to establish public health policies for suicide prevention and suggest the prioritization of resource allocation for mental health of individuals based on individual characteristics.

Individual and regional characteristics associated with changes in mental health before and during the COVID-19 pandemic in South Korea.

Mental health has been a major public health concerns during the COVID-19 pandemic. This study investigated the effects of COVID-19 on mental health and whether individual and regional characteristics are associated with the changes in mental health. We estimated district-specific changes in the prevalence of moderate stress, extreme stress, and depression before and during the COVID-19 pandemic after adjusting for the time trend of mental health outcomes. Then, a meta-regression was conducted to examine the associations between district-level characteristics and changes in mental health due to the pandemic. The prevalence of moderate stress, extreme stress, and depression increased during the pandemic and the increases were more prominent in districts with high population density and in individuals aged 19-59 years, with a high education level, and with high household income. The % with reduced physical activity due to the pandemic were positively associated with increases in stress; while, the % that have mutual trust among neighbors and the number of sports facilities were negatively associated with increases in stress. Local tax per person had a positive association with increase in depression. Our study provides epidemiological evidence into the mental health consequences of the pandemic, which can inform the priority of resource allocation for managing mental health.

Comparative analysis of cardio-cerebrovascular complications in immigrants and native-born Koreans with diabetes: Risk factors and perspectives.

BACKGROUND: Given the rapidly increasing number of immigrants, it is crucial to address health care issues involving immigrants to facilitate their safe and secure settlement. Especially for common chronic diseases, such as diabetes, immigrants face more complex obstacles to manage their chronic conditions than do native-born residents. Therefore, we aimed to assess differences in the incidence and associated risk factors of cardio-cerebrovascular (CCV) complications of immigrants compared with native-born Koreans with diabetes. METHODS: Immigrants and native-born Koreans who had new diagnosis of diabetes and simultaneously received anti-diabetic prescriptions in 2012 were defined by using Korean National Health Insurance Claim Database(KNHICD). CCV complications were assessed at a 3-year follow-up from the index date. We assessed differences in the CCV complications and risk factors using multiple cox regression models. RESULTS: In total, 4,008 patients (668 of immigrants and 3,340 of native-born Koreans) who had newly diagnosed diabetes and simultaneously received anti-diabetic prescriptions in 2012 were selected. Immigrants with diabetes were at a 1.39 times higher risk of having CCV complications than native-born Koreans with diabetes (95% CI: 1.021-1.881). Patients who had a usual sources of care (USC) presented a significantly reduced risk of cardio-cerebrovascular complication (HR: 0.452; 95% CI: 0.342-0.598) in both immigrants and native Koreans. In subgroup analysis in immigrants, patients having USC showed decreased risk of CCV incidence (HR: 0.35, 95% CI: 0.175-0.703), whereas >60 years old and Charlson comorbidity index (CCI) score >1 presented increased risk of CCV complications. CONCLUSION: Immigrants with diabetes have a higher risk of CCV complications than native-born Koreans with diabetes. However, having a USC significantly decreased the risk of CCV complications. Therefore, the utilization of USC will benefit to reduce diabetic complications in immigrants as well as reduction of overall health care cost burden, it would be necessary to implement USC in diabetes care at the initial disease stage.

Excess out-of-hospital cardiac arrests due to ambient temperatures in South Korea from 2008 to 2018.

Out-of-hospital cardiac arrest (OHCA) is a notable public health issue with negative outcomes, such as high mortality and aftereffects. Additionally, the adverse effects of extreme temperatures on health have become more important under climate change; however, few studies have investigated the relationship between temperature and OHCA. In this study, we examined the association between temperature and OHCA and its underlying risk factors. We conducted a two-stage time-series analysis using a Poisson regression model with a distributed lag non-linear model (DLNM) and meta-analysis, based on a nationwide dataset from South Korea (2008-2018). We found that 17.4% of excess OHCA was attributed to cold, while 0.9% was attributed to heat. Based on central estimates, excess OHCA attributed to cold were more prominent in the population with hypertension comorbidity (31.0%) than the populations with diabetes (24.3%) and heart disease (17.4%). Excess OHCA attributed to heat were larger in the populations with diabetes (2.7%) and heart disease comorbidity (2.7%) than the population with hypertension (1.2%) based on central estimates. Furthermore, the time-varying excess OHCA attributed to cold have decreased over time, and although those of heat did not show a certain pattern during the study period, there was a weak increasing tendency since 2011. In conclusion, we found that OHCAs were associated with temperature, and cold temperatures showed a greater impact than that of hot temperatures. The effects of cold and hot temperatures on OHCA were more evident in the populations with hypertension, diabetes, and heart diseases, compared to the general population. In addition, the impacts of heat on OHCA increased in recent years, while those of cold temperatures decreased. Our results provide scientific evidence for policymakers to mitigate the OHCA burden attributed to temperature.

Effects of urbanization on vulnerability to heat-related mortality in urban and rural areas in South Korea: a nationwide district-level time-series study.

BACKGROUND: Although urbanization is often an important topic in climate change studies, the complex effect of urbanization on heat vulnerability in urban and rural areas has rarely been studied. We investigated the disparate effects of urbanization on heat vulnerability in urban and rural areas, using nationwide data. METHODS: We collected daily weather data for all 229 administrative districts in South Korea (2011-17). Population density was applied as an urbanization indicator. We calculated the heat-mortality risk using a distributed lag nonlinear model and analysed the relationship with population density. We also examined district characteristics that can be related to the spatial heterogeneity in heat-mortality risk. RESULTS: We found a U-shaped association between population density and heat-mortality risk, with the highest risk for rural populations; in urban areas, risk increases with increasing population density. Higher heat-mortality risk was associated with a lower number of hospital beds per person and higher percentage of people requiring recuperation. The association between hospital beds and heat-mortality risk was prominent in high-density urban areas, whereas the association between the percentage of people requiring recuperation and heat-mortality risk was pronounced in rural areas. CONCLUSIONS: Our findings indicate that the association between population density and heat-mortality risk is different in urban and rural areas, and that district characteristics related to heat-mortality risk also differ by urbanicity. These results can contribute to understanding the complex role of urbanization on heat vulnerability and can provide evidence to policy makers for prioritizing resources.

Additive interaction of mid- to late-life depression and cerebrovascular disease on the risk of dementia: a nationwide population-based cohort study.

BACKGROUND: Dementia is a progressive neurocognitive disease with a substantial social burden. No apparent breakthroughs in treatment options have emerged so far; thus, disease prevention is essential for at-risk populations. Depression and cerebrovascular disease (CVD) are independent risk factors for dementia, but no studies have examined their interaction effect on dementia risk. This study aimed to identify the association of depression and CVD with the risk of dementia and evaluate whether dementia risk among patients with comorbid depression and CVD is higher than the sum of the individual risk due to each condition. METHODS: A population-based cohort study was conducted to analyze the Korean National Health Insurance Service-National Sample Cohort data of all individuals over 50 years of age. Individuals who had not been diagnosed with dementia at baseline were included and followed up from January 1, 2005, to December 31, 2013. A time-varying Cox proportional hazard regression model adjusted for potential confounding factors was used for the analysis. The interaction between depression and CVD was estimated based on the attributable proportion (AP), relative excess risk due to interaction (RERI), synergy index (SI), and multiplicative-scale interaction. RESULTS: A total of 242,237 participants were included in the analytical sample, of which 12,735 (5.3%) developed dementia. Compared to that for participants without depression or CVD, the adjusted hazard ratio for the incidence of dementia for those with depression alone was 2.35 (95% confidence interval [CI] 2.21-2.49), CVD alone was 3.25 (95% CI 3.11-3.39), and comorbid depression and CVD was 5.02 (95% CI 4.66-5.42). The additive interaction between depression and CVD was statistically significant (AP-0.08, 95% CI 0.01-0.16; RERI-0.42, 95% CI 0.03-0.82; SI-1.12, 95% CI 1.01-1.24). The multiplicative interaction was significant too, but the effect was negative (0.66, 95% CI 0.60-0.73). CONCLUSIONS: In this population-based nationwide cohort with long-term follow-up, depression and CVD were associated with an increased risk of dementia, and their coexistence additively increased dementia risk more than the sum of the individual risks.

Assessment of a medication management program targeting hypertension and diabetes patients: Impact on medication adherence.

BACKGROUND: The National Health Insurance Service in South Korea has conducted a telephone outreach program to improve medication adherence for hypertension and diabetes patients since 2014. OBJECTIVES: To evaluate the direct outcomes of the program. METHODS: Patients were identified among those who visited an outpatient clinic at least twice or used an inpatient service at least once for hypertension or diabetes during 6-month intervals and who were nonadherent based on the proportion of days covered (PDC) calculated. As a preliminary intervention, participants were mailed an information leaflet on their own medication adherence and other tips for effective self-management of chronic diseases. For the intervention, two phone calls and three phone messages were made to patients by 24 participating regional offices. Ultimately, 2,428 hypertension patients and 884 diabetes patients received the intervention. Propensity matching was used based on age, sex, and the Charlson Comorbidity Index to select 12,140 hypertension and 4,420 diabetes patients as controls in the non-participating regions. The outcome was PDC. Multivariate ordinary least squares or logistic regression analysis were used with difference-in-difference specification. RESULTS: The adjusted quarterly PDC increased by 1.96%p for hypertension (p = 0.023) and by 7.79%p for diabetes patients (p < 0.001). Approximately 40.6% and 51.7% of hypertension and diabetes patients in the treatment arm (p = 0.0069) became adherent after the intervention, whereas the corresponding proportions were 37.7% and 41.4% (p < 0.001) in the control group. Both treatment groups showed a higher likelihood of good medication adherence (hypertension: odds ratio = 1.157, 95% CI [1.058, 1.265]; diabetes: odds ratio = 1.532, 95% CI [1.323, 1.774]). The control group, who received only a print intervention with a mailed leaflet, also showed a dramatic increase in medication adherence. CONCLUSIONS: An insurer-coordinated telephone-administered program resulted in improvement of medication adherence among patients with hypertension and diabetes.

Antidepressant adherence and its predictors in immigrants with depression: A population-based study.

ABSTRACT: Immigrants in Korea are relatively vulnerable in terms of medication self-management and have low levels of medication adherence. We aimed to evaluate antidepressant adherence and its patterns in immigrants and to identify predictors of nonadherence.In this matched cohort study using the National Health Insurance claims database, immigrants who were newly prescribed antidepressants were identified (n = 2,398). The immigrants were matched with native-born Koreans in a 1:1 ratio. Antidepressant adherence was measured by the medication possession ratio at monthly intervals. Logistic regression was performed to compare antidepressant nonadherence between immigrants and native-born Koreans, and to identify factors affecting immigrants' nonadherence.The average medication possession ratio of immigrants was 27.1%, which was lower than that of native-born Koreans (30.9%) (P = .038). Immigrants had a lower likelihood of adherence than native-born Koreans (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.3-0.92). Older age, visiting a psychiatrist for the first diagnosis of depression (OR 2.24, 95% CI 1.60-3.13), achieving appropriateness of care (OR 3.54, 95% CI 2.51-4.98), and having a usual source of care (OR 1.69, 95% CI 1.25-2.27) were associated with a higher likelihood of adherence in immigrants.This study showed that antidepressant adherence of immigrants was lower than that of native-born Koreans. However, it appears that visiting a psychiatrist, achieving appropriateness of care, and having a usual source of care might increase antidepressant adherence among immigrants. Further research that focuses on cultural and/or linguistic factors affecting immigrants' adherence and healthcare utilization is suggested as a way to increase adherence.

Risk Factors and the Usual Source of Care on Non-Adherence to Antihypertensive Drugs in Immigrants with Hypertension.

BACKGROUND: Immigrants are vulnerable to suboptimal health care utilization including non-adherence of medication use. Thus, we aimed to identify the potential risk factors of non-adherence and evaluate whether utilizing a usual source of care was associated with medication adherence in immigrants. METHODS: We utilized the Korea National Health Insurance Claims Database between 2012 and 2015. Cases were immigrants who had antihypertensive prescriptions at the time of hypertension diagnosis in 2012. Controls were native-born Koreans with hypertension who were 1:1 matched to immigrants by age, sex, and Charlson comorbidity index. We used the medication possession ratio for three years to assess the adherence to antihypertensive drugs. The likelihood of non-adherence was evaluated between cases and controls by multivariate linear regression models stratified by age, sex, and number of clinic visits. We assessed the potential risk factors of non-adherence in immigrants by multivariate linear regression and logistic regression models, respectively. RESULTS: In total, 4114 immigrants and 4114 matched native-born Koreans with hypertension were included. The mean MPR was significantly lower in immigrants (56% vs 70%, p<0.0001). Immigrants showed almost two times the level of non-adherence as native-born Koreans (odds ratio [OR], 2.01; 95% confidence interval [CI], 1.83-2.21). Stratified analyses on non-adherence presented the highest non-adherence (2.28 times) in immigrants in the younger group (30-49 years old) and the lowest non-adherence in immigrants in 65 and old group where the risk was 1.69 times higher than native Korean with the same age. The absence of a usual source of care significantly increased medication non-adherence by 1.31 to 1.58 times among immigrants. CONCLUSION: When the number of visited clinics increased, the degree of non-adherence increased consistently. Therefore, the systematization of registering with primary care (a usual source of care) might be a modifiable health care strategy to improve health care outcomes in immigrants.

Roles of urban heat anomaly and land-use/land-cover on the heat-related mortality in the national capital region of South Korea: A multi-districts time-series study.

The urban heat anomaly has been suggested as a representative risk factor for human health in metropolitan areas, but few studies have measured a quantitative increase in risk due to the urban heat anomaly on heat-related mortality in the summer season or assessed the role of various types of land-use/land-cover (LULC), which may contribute to the urban heat anomaly. In this study, we evaluated the association between the urban heat anomaly and heat-related mortality risk in the summer and the potential roles of multiple types of LULC indicators. We used district-level time-series and cadastral data from 51 urban districts in the national capital region of South Korea. We applied a two-stage analysis. In the first stage, we estimated the district-specific heat-related mortality risk by using a distributed lag non-linear model. In the second stage, we used a meta-analysis to pool the estimates across all districts and calculate the association between the urban heat anomaly/LULC indicators and heat-related mortality risk. We found that the higher urban heat anomaly was related to lower vegetation and higher urban surface indicators, and the urban heat anomaly was positively associated with the heat-related mortality risk. The association between the urban heat anomaly and the heat-related mortality risk was more pronounced in the elderly (age ≥ 65 years) and female population than in the non-elderly and male population. We also found that the LULC indicators affected the heat-related mortality only through the urban heat anomaly. Our findings indicate that urban areas may be more vulnerable to heat-related mortality risk as determined by the urban heat anomaly. These results suggest a need for urban heat mitigation strategies such as increased vegetation or surface albedo to help reduce heat-related mortality risk.

Heatwave-Related Mortality Risk and the Risk-Based Definition of Heat Wave in South Korea: A Nationwide Time-Series Study for 2011-2017.

Studies on the pattern of heatwave mortality using nationwide data that include rural areas are limited. This study aimed to assess the risk of heatwave-related mortality and evaluate the health risk-based definition of heatwave. We collected data on daily temperature and mortality from 229 districts in South Korea in 2011-2017. District-specific heatwave-related mortality risks were calculated using a distributed lag model. The estimates were pooled in the total areas and for each urban and rural area using meta-regression. In the total areas, the threshold point of heatwave mortality risk was estimated at the 93rd percentile of temperature, and it was lower in urban areas than in rural areas (92nd percentile vs. 95th percentile). The maximum risk of heatwave-related mortality in the total area was 1.11 (95% CI: 1.01-1.22), and it was slightly greater in rural areas than in the urban areas (RR: 1.23, 95% CI: 0.99-1.53 vs. RR: 1.10, 95% CI: 1.01-1.20). The results differ by age- and cause-specific deaths. In conclusion, the patterns of heatwave-related mortality risk vary by area and sub-population in Korea. Thus, more target-specific heatwave definitions and action plans should be established according to different areas and populations.

Socioeconomic determinants affecting the access and utilization of depression care services in immigrants: A population-based study.

BACKGROUND: It is imperative to address the health problems faced by immigrants in their destination countries in light of the current magnitude of migration processes worldwide. We aimed to evaluate the socioeconomic determinants of healthcare utilization in immigrants with depression. METHOD: A population-based cohort comprising all immigrants who were eligible for National Health Insurance coverage (permanent residents, marriage immigrants, and naturalized citizens) using the National Health Insurance Claims Database in 2011-2013 was established. Cases were defined as immigrants with new-onset depression. Controls were new-onset Korean patients with depression matched by age, sex, and Charlson comorbidity index in a 1:2 ratio. Appropriateness of care (AOC) was defined as visiting a clinic for depression management at least 3 times in the first 12 weeks and 4 times thereafter until 12 months post-cohort entry. RESULTS: A total of 2,378 immigrants and 4,756 matched Korean patients were identified. Of the immigrants, 30.0% achieved AOC, in contrast to 38.7% of Koreans (p < .0001). Adjusting for possible covariates, AOC was less likely for immigrants (adjusted OR (aOR), 0.760; 95% CI: 0.670-0.863). Medical Aid (aOR, 2.309; 95% CI, 1.479-3.610), rural residence (aOR, 1.536; 95% CI, 1.054-2.237), the presence of a psychiatric comorbidity (aOR, 1.912; 95% CI, 1.484-2.463), and visiting a psychiatrist (aOR, 2.387; 95% CI, 1.821-3.125) were associated with an increased likelihood of AOC in immigrants. CONCLUSION: Socioeconomic determinants included insurance type (Medical Aid and National Health Insurance), place of residence, psychiatric comorbid status, doctor specialty, easy access to medical services (clinic-based), and a SSRI-based treatment regimen. Those predictors should be taken into account when developing healthcare strategies for immigrants.