South Korean National Health Insurance Research Articles

Nurse's, physician's and family member's experiences of withholding or withdrawing life-sustaining treatment process in an intensive care unit.

To explore nurse's, physician's and family member's experiences of withholding or withdrawing life-sustaining treatment in an intensive care unit. In South Korea, withholding or withdrawing life-sustaining treatment is legalised by the enforcement of the Hospice, Palliative Care and Life-sustaining Treatment Decision-making Act (2018). The Act (2018) is the first legal ground for making decisions regarding life-sustaining treatment in South Korea. Focused ethnography. The standards for reporting qualitative research checklist is used. Interview data are collected between August 2018 and January 2019 using semi-structured interviews with 23 nurses, 10 physicians and four family members in a South Korean intensive care unit. The interview data are analysed following the thematic analysis of Braun and Clarke. An overarching theme of 'constructing death' is identified from the experiences of nurses, physicians and family members regarding withholding or withdrawing life-sustaining treatment in a South Korean intensive care unit. Family members had the strongest power in the withholding or withdrawing life-sustaining treatment process whilst the process had to be based on medical consideration. All the research participants shared the purpose and motivation of withholding or withdrawing life-sustaining treatment as the dying patient's dignity. Due to the South Korean national health insurance system, the relationships between medical staff and family members were driven by customer ideology. The impact and linkage of the context of familism culture and health insurance with the process of withholding or withdrawing life-sustaining treatment in South Korea are shown in this research. The findings of this research inspire future studies to uncover the impact of the cultural context in the decision-making process of a patient's death, to explore the dynamics of family members under cultural values and to explore the influence of the healthcare system and medical costs on the relationships between medical staff and family members. By integrating the experiences of nurses, physicians and family members, the findings of this study inform the shared values in the context of familism culture and the health insurance system. In particular, understanding family dynamics when a patient's dying and death as a result of withholding or withdrawing life-sustaining treatment informs nurses to provide quality of care in the intensive care setting. Therefore, the findings of this research contribute to distinguishing the priority in care when withholding or withdrawing life-sustaining treatment, rapidly changing the aims of care from the patient's recovery to a dignified death.

New, long-term opioid use after lung cancer surgery is associated with reduced 2-year survival: a retrospective population-based cohort study in South Korea

IntroductionWe aimed to investigate the proportion and associated factors for new long-term opioid use and its long-term effects after lung cancer surgery.MethodsThe South Korean National Health Insurance Database was used...

Changes In Catastrophic Health Expenditures For Major Diseases After A 2013 Health Insurance Expansion In South Korea

The South Korean National Health Insurance scheme has lacked sufficient coverage scope (services covered) and depth (costs covered) since it achieved national coverage in 1989. The government implemented two separate welfare plans (2004-08 and 2009-12) to improve the financial protection of National Health Insurance by mainly focusing on costs covered. The third plan (initiated in 2013) was the most comprehensive, addressing both scope and depth. We evaluated the impact of this benefit expansion policy for four categories of major disease (cancer, cardiac disease, cerebrovascular disease, and rare diseases) on catastrophic health expenditures, impoverishment, and unmet need. Using 2012-17 Korean Health Panel Survey data, we performed difference-in-differences analyses and triple-difference analyses to examine the differential impact of policy across income groups. The policy reduced catastrophic health expenditures among beneficiary households across almost all postpolicy years. However, there was no average effect on reducing household impoverishment or unmet need. The policy had mixed effects by income but did not generally favor low-income households. To provide stronger financial protection, the policy must address issues beyond expanding coverage, such as provider payment structure. In addition, special policy measures for low-income households need to be adopted.

Impacts of Symptomatic HIV Infection on In-Hospital Cardiopulmonary Resuscitation Outcomes: 
A Population-Based Cohort Study in South Korea

BackgroundThe impact of HIV infection on survival outcomes after in-hospital cardiopulmonary resuscitation (ICPR) remains controversial. This study aimed to investigate the impacts of HIV infection on both short-term and long-term outcomes after ICPR.MethodsThis nationwide, population-based cohort study used data taken from the South Korean National Health Insurance Service database. All adult (≥18 years old) patients who experienced ICPR between January 1, 2010, and December 31, 2019, were included.ResultsA total of 298 676 adult patients who underwent ICPR were initially included in the analysis. Among them, 586 (0.2%) patients were assigned to the patients with symptomatic HIV infection (PWH) group, while 298 090 (99.8%) patients were assigned to the control group. After 1:10 propensity score (PS) matching, 586 patients in the PWH group and 5845 patients in the control group were included in the analysis. Logistic regression analysis after PS matching showed that the PWH group had a 20% lower live discharge rate after ICPR compared with the control group (odds ratio, 0.80; 95% CI, 0.65–0.97; P = .024). However, Cox regression analysis after PS matching showed that the risks of 6-month survival (hazard ratio [HR], 1.01; 95% CI, 0.93–1.11; P = .768) and 1-year survival (HR, 1.02; 95% CI, 0.93–1.11; P = .702) were not significantly different between the PWH and control groups.ConclusionsAlthough the PWH group showed lower live discharge rates compared with the control group after ICPR, long-term survival outcomes from 6 months and 1 year were not significantly different.

Real-world Treatment Patterns, Outcomes, and Healthcare Resource Utilization in Newly Treated Korean Patients With Asthma: A Retrospective Cohort Study.

PurposeAlthough asthma treatment guidelines recommend regular inhaled medication, real-world treatment patterns and outcomes in South Korea have not been examined. We examined real-world treatment patterns and outcomes among patients treated for asthma in South Korea.MethodsThis retrospective cohort study utilized data from the South Korean National Health Insurance database (2013–2016). Newly treated patients with asthma aged ≥18 years without history of chronic obstructive pulmonary disease were included. Initial and maintenance medication prescriptions were examined. Treatment discontinuation and switch were described. Asthma exacerbation rates, poor asthma control, and healthcare resource utilization (HRU) were compared between maintenance treatment groups (inhaled versus oral) using adjusted incidence rate ratios (aIRR) and hazard ratios (aHR).ResultsOverall, 1,054,707 patients initiated any asthma medication; 37,868 patients initiated inhaled (n = 9,983, 26.4%) or oral (n = 27,885, 73.6%) maintenance medication. More patients initiating inhaled versus oral asthma medication discontinued treatment within 12 months (94.4% vs. 86.3%; P < 0.0001). Patients treated with inhaled and oral medication switched treatment (2.5% and 2.3%; P = 0.4160, respectively). Patients initiating inhaled medication had significantly lower rates of asthma exacerbation (aIRR, 0.52; 95% CI, 0.39–0.69), lack of asthma control (aHR, 0.55; 95% CI, 0.48–0.62; P < 0.0001), all-cause and asthma-related HRU versus oral medication.ConclusionsDespite current asthma guidelines, more patients in South Korea were prescribed oral than inhaled medications, resulting in suboptimal asthma management and increased HRU. This study highlights the need to reduce oral corticosteroid prescriptions for optimized treatment in asthma management.

Incidence and prevalence of pressure ulcers in hospitals: 10-year cohort study.

Pressure ulcers (PUs) are a serious problem in patients with multiple comorbidities and are associated with a longer duration of hospital stay and higher medical costs. The aetiology and rate of PU occurrence in South Korea remains unclear. Therefore, we aimed to determine the incidence, prevalence, mortality and common comorbidities of hospitalised patients with PUs in the South Korean healthcare system. A 10-year cohort study using the healthcare insurance reimbursement claims from the South Korean National Health Insurance System database. Patients diagnosed with a PU on admission to hospital [ICD-10: L89 + procedure code] between January 2002 and December 2016 were included and their comorbidities evaluated. Patients <20 years of age and recurrent PU cases were excluded. Incidence, prevalence, survival rate and risk factors related to survival rate of patients with PUs were determined. The study population in 2006 was 36,195,121 (all patients admitted to hospital that year), which changed yearly because of the inclusion of additional patients who met the study inclusion criteria, and removal of patients who had died during the year. Standardised PU incidence rate decreased from 17.1 in 2006 to 14.9 in 2015 per 10,000 people. Standardised PU prevalence also showed a slightly decreasing trend from 20.2 in 2006 to 18.9 in 2015 per 10,000 people. This findings of this 10-year study showed that incidence and prevalence of PUs markedly increased with age after the seventh decade. Incidence of PUs increased in patients with pneumonia, cerebral infarction, sepsis, femoral neck fracture and malignant neoplasm of the bronchus. Patients with femoral neck fracture and cerebral infarction showed a higher rate of survival than those with other high-risk comorbidities.

THE NATIONWIDE INCIDENCE OF RETINAL ARTERY OCCLUSION FOLLOWING DIALYSIS AS A RESULT OF END-STAGE RENAL DISEASE: 2004 Through 2013.

To examine the incidence and risk of retinal artery occlusion (RAO) in patients who have undergone dialysis in Korea. A nationwide, population-based study using South Korean national health insurance data from 2004 to 2013 was used for analysis. All patients who began dialysis between 2004 and 2013 and the same number of control subjects were selected via propensity score matching. The incidence of RAO in the dialysis and control cohorts was calculated for 2004 to 2013 using washout data from 2003. The multivariable Cox proportional hazards model was used to evaluate the risk of developing RAO in dialysis patients. Cumulative RAO incidence curves were generated using the Kaplan-Meier method. Whether dialysis modalities influenced the incidence of RAO was also evaluated. Seventy-six thousand seven hundred and eighty-two end-stage renal disease patients on dialysis were included in the dialysis cohort, and 76,782 individuals were included in the control cohort. During the study period, 293 patients in the dialysis cohort and 99 patients in the control cohort developed RAO. The person-years incidence of RAO was significantly higher in the dialysis cohort than in the control cohort (dialysis = 1.1/1,000 person-years; control = 0.3/1,000 person-years; P < 0.001). The incidence of RAO was not significantly different between the two methods of dialysis (hemodialysis vs. peritoneal dialysis; P = 0.25, log-rank test). The current study provided epidemiological evidence that undergoing dialysis for end-stage renal disease was associated with an increased risk of developing RAO. The incidence of RAO rapidly increased as the duration of dialysis increased. These results strengthen the significant role of the renal function in retinal vascular disease.

Increased metabolic variability is associated with newly diagnosed depression: A nationwide cohort study

BackgroundThe effect of dynamic changes in metabolic parameters over time on the development of depression has yet to be examined. In this study, we aimed to determine the association between the variability of metabolic parameters and the development of depression using nationally representative data. MethodsWe used health examination data provided by the South Korean National Health Insurance System (NHIS) and included those who underwent the examination ≥ 3 times within five years of enrollment, without a previous history of depression (n = 9,058,424). The variability of each metabolic parameter including weight circumference, blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, and triglyceride levels was estimated using variability independent of mean (VIM) indices. High variability was defined as the highest quartile (Q4) of variability. ResultsEach metabolic parameter with high variability was associated with a higher risk of newly diagnosed depression compared to those with low variability, after adjusting for age, sex, smoking, alcohol drinking, regular exercise, income status, baseline diabetes, hypertension, and dyslipidemia. As the number of highly variable metabolic parameters increased, the risk for newly diagnosed depression increased even after adjusting for the aforementioned covariates (hazard ratio (HR) = 1.4, 95% confidence interval (CI): 1.3 – 1.4 in those with five highly variable parameters compared to those with no highly variable parameter). Limitationsrelatively short observation period; no systematic measure of depression severity. ConclusionsOur results suggest that the variability of metabolic parameters is an independent risk factor for depression.

Fenofibrate Use Is Associated With Lower Mortality and Fewer Cardiovascular Events in Patients With Diabetes: Results of 10,114 Patients From the Korean National Health Insurance Service Cohort.

We investigated the long-term clinical efficacy of fenofibrate use with regard to mortality and cardiovascular outcomes in patients with type 2 diabetes. We performed a population-based cohort study using data of the South Korean National Health Insurance Service from 2003 to 2014. Of 63,727 participants with diabetes aged 40-79 years, 5,057 users of fenofibrate only were compared with 5,057 nonusers of fenofibrate and/or omega-3 fatty acid with 1:1 propensity matching. The primary end point was a composite of myocardial infarction, stroke, percutaneous coronary revascularization, and cardiac death for a median of 3 years. The primary end point was significantly lower in fenofibrate users compared with those using neither fenofibrate nor omega-3 fatty acid (13.4 vs. 15.5 per 1,000 person-years; hazard ratio [HR] 0.76; 95% CI 0.62-0.94; P = 0.010). Cardiac death (1.8 vs. 3.1 per 1,000 person-years; HR 0.59; 95% CI 0.352-0.987; P = 0.0446), all-cause death (7.6 vs. 15.3 per 1,000 person-years; HR 0.437; 95% CI 0.340-0.562; P < 0.0001), and stroke (6.5 vs. 8.6 per 1,000 person-years; HR 0.621; 95% CI 0.463-0.833; P = 0.0015) were significantly lower in the fenofibrate group. When the duration of fenofibrate use was stratified by quartile, the risk decreased in quartile 4, with an HR of 0.347 (95% CI 0.226-0.532; P < 0.0001). In subgroup analysis, the favorable effect of fenofibrate was sustained consistently across all subsets of patients, including those classified by LDL cholesterol, HDL cholesterol, and triglyceride levels. Use of fenofibrate was associated with a lower rate of total and cardiac mortality and cardiovascular events in patients with type 2 diabetes during a 3-year follow-up in real-world large populations.

Association between Skin Cancer and Systemic and Ocular Comorbidities in South Korea.

Background: In this study, we investigated the associations between various systemic and ocular comorbidities and skin cancer, in a nationwide cohort of South Koreans. Method: We reviewed the data of 1,103,302 individuals in the South Korean National Health Insurance Service-National Sample Cohort database from 2002 to 2015. Of these, 1202 individuals diagnosed with skin cancer from 2004 were included in the study group. The control group was matched in a 1:5 ratio based on propensity scores. Results: The prevalence rates of melanoma and non-melanoma skin cancer increased from 2004 to 2015. Multivariate logistic regression analysis revealed that, among the various systemic conditions, hypertension was significantly associated with skin cancer, while among ocular comorbidities, macular degeneration showed a significant association with skin cancer. Conclusions: This is the first study to demonstrate associations between skin cancer and various systemic and ocular comorbidities. The results suggest that hypertension and macular degeneration may increase the risk of skin cancer development, or vice versa. Further studies are needed to evaluate the causal relationships between these conditions.

Long-term mortality associated with depression among South Korean survivors of extracorporeal membrane oxygenation.

IntroductionDepression is an important sequela in critically ill patients. However, its prevalence after extracorporeal membrane oxygenation (ECMO) therapy and its association with long‐term mortality remain controversial.MethodsData were extracted from the South Korean National Health Insurance Service database in this population‐based cohort study. Adults who received ECMO therapy from 2006 to 2014 were included. Survivors of ECMO were defined as patients who underwent ECMO and survived over 365 days after the initiation of ECMO therapy.ResultsA total of 3,055 survivors of ECMO were included in the final analysis. They were classified into the pre‐ECMO depression group (n = 275 [9.0%]), post‐ECMO depression group (n = 331 [10.8%]), and other ECMO survivor group. In the multivariable Cox regression model, a 1.52‐fold higher mortality was observed in the post‐ECMO depression group than in the other groups (hazard ratio, 1.52; 95% confidence interval, 1.17–1.96; p = .002). However, there was no statistically significant difference between the pre‐ECMO depression group and the other groups (p = .075).ConclusionsThe prevalence of pre‐ and post‐ECMO depression was 9.0% and 10.8%, respectively. Additionally, post‐ECMO depression was associated with an increased 5 year all‐cause mortality; however, pre‐ECMO depression was not.

Visit-to-visit changes in fasting blood sugar and the risk for cardiovascular disease and mortality in the Korean population: a nationwide population-based cohort study.

The importance of continuous monitoring of fasting blood sugar (FBS) levels of diabetic patients has been established. An observational prospective study was conducted. Our analysis included 1,700,796 individuals from the nationwide South Korean National Health Insurance System cohort. FBS variability was measured by standard deviation (SD). Kaplan-Meier curves demonstrated elevated disease probability in the higher FBS fluctuation group compared with the lower FBS fluctuation group. After adjusting for confounding variables, Cox proportional hazards analysis showed that the hazard ratios of 411 individuals in the highest quartile of SD variation of FBS were 1.77 (95% confidence interval 1.37-2.28, p<0.001) compared with the lowest quartile of SD variation of FBS. The impact of FBS fluctuation on the risk of cardiovascular diseases (CVDs), cerebrovascular diseases, CVD mortality and all-cause mortality in the highest quartiles of diabetic and non-diabetic individuals was statistically significant. Visit-to-visit FBS variability has prognostic value for predicting micro- and macrovascular disease, cardiovascular mortality, and all-cause mortality.

Real-world data analysis of the clinical and economic burden and risk factors in patients with major depressive disorder with an inadequate response to initial antidepressants

Aim We aimed to determine the incidence of and identify the factors associated with treatment-resistant depression (TRD), psychiatric conditions, hospitalization, and cost in patients with major depressive disorder (MDD) who were treated using second-line strategies after an inadequate response to initial antidepressants (AD). Materials and methods Using South Korean National Health Insurance claims data (1 January 2013 to 30 June 2018), we conducted a retrospective cohort analysis in newly treated patients with MDD who subsequently switched or added AD, or added atypical antipsychotics (AAPs) as a second-line treatment. We assessed the incidence of treatment-resistant depression (TRD), psychiatric conditions, and hospitalization for the first 2 years and costs in the third year. Odds ratios (ORs) or relative ratios were estimated using logistic and linear regression models to identify the risk factors for clinical and economic outcomes. Results In 15,887 patients, the TRD was 16.81% during the 24-month follow-up period (14.14% in switching AD, 19.65% in adding AD, and 19.91% in adding AAP; p < 0.0001). When adding AD or AAP, the OR of TRD was 1.43 (95% confidence interval (CI): 1.30–1.56) and 1.42 (95% CI: 1.23–1.65), respectively, compared to switching AD. However, these factors were not associated with the incidence of psychiatric conditions. Adding AAP increased hospitalization (OR = 1.25, 95% CI: 1.11–1.41), the number of inpatient days by 2.57-fold (95% CI: 1.75–3.76), and cost by 1.20-fold (95% CI: 1.02–1.40), compared to switching AD; adding AD did not show a significant association with these outcomes. Conclusions In patients with MDD with inadequate responses to initial AD, TRD still occurred after subsequent treatments according to clinical guidelines. Since the effectiveness of second treatment strategies can differ in reality, further analysis of the clinical and economic evidence regarding second treatment strategies, such as adding AD or AAP, is needed using real-world data.

Incidence and etiology of sudden cardiac arrest in Koreans: A cohort from the national health insurance service database.

The incidence of sudden cardiac arrest (SCA) in Asians is lower than that seen in Western populations, but there are few available data on the incidence and associated cardiac etiology of SCA in Asians. From 2002 to 2013, patients with SCA were analyzed using a cohort from the South Korean National Health Insurance Service (NHIS) coded database. Sudden unexplained death syndrome (SUDS) was defined as cryptogenic arrest, excluding that of non-cardiac origin, coronary artery disease (CAD), cardiomyopathy (CM), and valvular heart disease. During the 12-year study period, 5,973 patients (0.53%) from the total cohort of 1,125,691 had a cardiac arrest code. The overall incidence of arrest was 48.7 per 100,000 person-years (95% CI 16.6–18.0). The incidence of primary SCA excluding those of non-cardiac origin was 16.1 per 100,000 person-years (95% CI 15.4–16.8). It was higher in males than in females (18.1 vs. 14.1 per 100,000 person-years). CAD was the most common cause of SCA (59.4%), and followed by CM (13.9%). SUDS accounted for 14.7% of SCA events. The risk of SCA had increased gradually from over 25 years old. Heart failure, atrial fibrillation and hypertension are major factors associated with SCA incidence. Our findings outline epidemiologic data for SCA and the proportion of associated cardiac etiology leads SCA in a large population.

Economic burden of subsequent fracture in osteoporosis patients in South Korea

Objectives This study aimed to assess the economic burden of subsequent fracture in osteoporosis patients with incident fracture. Methods The authors conducted a retrospective cohort analysis of the South Korean national health insurance claims data. Study subjects included osteoporosis patients aged ≥50 with incident fracture (July 1, 2014–June 30, 2015). Fracture-related 1-year healthcare cost was evaluated after incident fracture for patients with and without subsequent fracture, defined as a fracture occurring within 2 years from incident fracture at a different site or at the same site after 6-months washout period. Per-patient-per-month (PPPM) cost was calculated by dividing each patient’s cumulative healthcare cost until subsequent fracture with time-to-subsequent-fracture. For the patients without subsequent fracture, PPPM cost equaled 1-year monthly cost. A generalized linear model (GLM) was used to estimate the ratio of increase in healthcare cost to assess the economic impact of subsequent fracture. Results A total of 73,717 osteoporosis patients with incident fracture were identified, consisting of 52.1% vertebral, 1.9% hip, and 46.0% non-vertebral-non-hip fractures. Subsequent fracture occurred in 17.9% of patients with average time-to-subsequent-fracture of 256 days. Patients with subsequent fracture had significantly higher 1-year healthcare cost after incident fracture than those without subsequent fracture ($4,307 vs $1,721) and the difference was greater in PPPM cost ($930 vs $141). GLM analysis showed that having subsequent fracture increased both 1-year healthcare cost and PPPM cost by 1.91-fold (95% CI = 1.87–1.95) and 6.14-fold (95% CI = 5.99–6.28), respectively. Conclusions Subsequent fracture imposes a substantial burden on osteoporosis patients and, therefore, more efforts are needed for preventing subsequent fracture among osteoporosis patients.

Incidence and associated risk factors for limb amputation among sepsis survivors in South Korea.

PurposePeripheral gangrene (PG) is a known complication requiring limb amputation among sepsis survivors; however, its incidence and associated risk factors remain controversial. We aimed to examine the incidence of limb amputation among sepsis survivors, and to investigate factors independently associated with limb amputation.MethodsIn this population-based cohort study, data obtained from the South Korean national health insurance service database between 2015 and 2016 were analyzed. A sepsis survivor was defined as someone having survived > 90 days after initiation of treatment for sepsis.ResultsOf 19,906 sepsis survivors, 163 (0.8%) had undergone surgical limb amputation. In a multivariable model, male sex (odds ratio [OR] 1.74, 95% confidence interval [CI] 1.26–2.40; P = 0.001), dopamine infusion (OR 1.78, 95% CI 1.22–2.60; P = 0.003), epinephrine infusion (OR 2.04, 95% CI 1.30–3.20; P = 0.002), continuous renal replacement therapy (OR 3.34, 95% CI 2.01–3.20; P < 0.001), diabetes mellitus (DM) without chronic complication (OR 1.73, 95% CI 1.19–2.51; P = 0.004), DM with chronic complication (OR 3.49, 95% CI 2.32–5.26; P < 0.001), and peripheral arterial disease (OR 6.79, 95% CO 3.70–12.46; P < 0.001) were associated with a higher incidence of limb amputation among sepsis survivors.ConclusionsIn South Korea, 0.8% of sepsis survivors underwent limb amputation for the treatment of PG. Furthermore, the incidence of limb amputation was higher among the sepsis survivors having some underlying diseases (DM and peripheral arterial diseases) or receiving certain vasopressor treatments (epinephrine and dopamine).Electronic supplementary materialThe online version of this article (10.1007/s00540-020-02858-9) contains supplementary material, which is available to authorized users.

Retinal Vein Occlusion and the Risk of Dementia: A Nationwide Cohort Study

Retinal vascular change is associated with changes in the brains of patients with dementia; however, there is limited evidence regarding the relationship between retinal vein occlusion (RVO) and risk of dementia. This study investigated the association between RVO and subsequent risk of dementia using a cohort consisting of the entire Korean population. Retrospective cohort study. This study was based on the data from participants ≥40 years of age who underwent health examinations between 2009 and 2010 provided by the South Korean National Health Insurance Service. The RVO group (n= 46,259) consisted of patients whose initial diagnoses were between 2006 and 2010. The comparison group (3 per RVO patient; n= 138,777) was selected using propensity score matching according to age, sex, and systolic blood pressure. Multivariate Cox proportional hazard regression models were performed. During a mean follow-up of 6.6 years, 14,727 cases of dementia developed. From the Kaplan-Meier curves, probabilities of cases for all types of dementia were significantly increased in the RVO group, relative to the comparison group (all log-rank P <.001). After all confounding variables were adjusted, the RVO group exhibited increased risks of subsequent all-cause dementia (hazard ratio [HR]: 1.16; 95% confidence interval [CI]: 1.12-1.21), Alzheimer's disease (HR: 1.15; 95% CI: 1.11-1.20), and vascular dementia (HR: 1.24; 95% CI: 1.12-1.37), relative to the comparison group. The presence of RVO was significantly associated with increased risks of all 3 types of dementia both in hypertensive and nonhypertensive individuals. In this large-scale population-based cohort study, RVO was significantly associated with increased risks of all-cause dementia, Alzheimer's disease, and vascular dementia.

Effect of Statins on the Risk of Poststroke Pneumonia: National Population-Based Cohort Study.

PurposeStatins are widely prescribed medications for treatment of dyslipidemia and prevention of cardiovascular disease. Beyond their lipid-lowering property, statins exhibit multiple pleiotropic and antimicrobial effects. We aimed to investigate the effect of statins on the long-term risk of pneumonia after acute ischemic stroke.MethodsThis retrospective observational research was performed using South Korean National Health Insurance Service claim data, which consist of population-based random sampling. We included patients discharged with acute ischemic stroke (I63 in the ICD10) and no prior history of pneumonia. The primary outcome measure was the occurrence of pneumonia determined based on ICD10 code J09–J18. Treatment with statins during follow-up was collected as a time-dependent variable based on prescription records.ResultsA total of 7,001 subjects with acute ischemic stroke and no prior history of pneumonia were included. During the mean 3.96-year follow-up, pneumonia occurred in 1,715 subjects (24.5%). On multivariate time-dependent Cox proportional hazard–regression analyses, significant preventive benefit of treatment with statins against pneumonia was noted (adjusted HR 0.86, 95% CI 0.77–0.97). Compared to no use of statin, adjusted HRs (95% CIs) for current use of low–intermediate high-intensity statins were 0.88 (0.78–0.99) and 0.49 (0.27–0.87), respectively.ConclusionOur retrospective national cohort study found reduced risk of poststroke pneumonia with statin therapy after acute ischemic stroke. Our study suggests that treatment with statins may have a preventive effect against the common complication of poststroke pneumonia.

Trends in long-term glucocorticoid use and risk of 5-year mortality: a historical cohort study in South Korea.

This study investigated trends in chronic glucocorticoid (GC) use in South Korea, and determined the association between chronic GC use and 5-year all-cause mortality. A sample cohort was extracted from the South Korean National Health Insurance database. Patients prescribed a continuous dose of GC for ≥30 days were defined as chronic GC users. Time-dependent Cox regression was used for statistical analysis, and chronic GC exposure was considered a time-varying variable. The prevalence of chronic GC use gradually increased from 0.16% in 2002 to 0.54% in 2015. In the 2010 cohort (n = 822,097), chronic GC users had a significantly 1.41-fold higher 5-year all-cause mortality compared with controls [hazard ratio: 1.41, 95% confidence interval (CI): 1.28-1.55, P < 0.001]. On sensitivity analysis, chronic high-dose GC users showed 1.52-fold (HR: 1.52, 95% CI: 1.32-1.76; P < 0.001) and low-dose GC users showed 1.34-fold (HR: 1.34, 95% CI: 1.18-1.51; P < 0·001) higher 5-year all-cause mortality, compared with controls; the disease-specific 5-year mortality risk in chronic GC users was highest due to musculoskeletal disease (HR: 9.50), followed by infectious and parasitic diseases (HR: 2.43), and respiratory disease (HR: 2.18). Numbers of chronic GC users gradually increased during 2002-2015; chronic GC use increased risks of 5-year all-cause mortality in the general adult South Korean population. This association was more evident among high-dose GC users (>5 mg/day of prednisolone). The risk of disease-specific mortality among chronic GC users was increased in those with musculoskeletal, infectious and parasitic, and respiratory diseases.

Association between Pulse Pressure and Onset of Dementia in an Elderly Korean Population: A Cohort Study

Objective: There is paucity of studies on the association between pulse pressure and the development of dementia, although this association has already been established. This study aimed at investigating the association between pulse pressure and the onset of dementia. Methods: We used the South Korean National Health Insurance Service claims cohort data to select 149,663 patients without dementia aged ≥60 years. We calculated adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia using Cox proportional hazard models according to a pulse pressure classification (<50, 50–59, 60–69, 70–79, 80–89, or 90+). Results: Compared to women with pulse pressure <50, those with pulse pressures of 50–59, 60–69, and 90+ had higher HRs for dementia (1.14, 1.22, and 1.03, respectively). These associations were particularly strong in those on Medicaid insurance and from rural regions. However, there were no statistically significant results among men. Conclusions: A higher pulse pressure was associated with an elevated risk of dementia in women aged >60 years, particularly those on Medicaid and from rural regions, possibly due to their inability to access hypertension and other medical treatment. The establishment of dementia indicators will help to guide future health policies for the prevention of dementia.