Disparities in cause-specific mortality by health insurance type and premium: evidence from Korean NHIS-HEALS cohort study, 2002-2019.

BACKGROUND: Although one's socioeconomic status affects health outcomes, limited research explored how South Korea's National Health Insurance (NHI) system affects mortality rates. This study investigated whether health insurance type and insurance premiums are associated with mortality. METHODS: Based on the National Health Insurance Service-Health Screening cohort, 246,172 men and 206,534 women aged ≥ 40 years at baseline (2002-2003) were included and followed until 2019. Health insurance type was categorized as employee-insured (EI) or self-employed-insured (SI). To define low, medium, and high economic status groups, we used insurance premiums at baseline. Death was determined using the date and cause of death included in the cohort. Cox proportional hazard models were used to analyze the association between insurance factors and the overall and cause-specific mortality. RESULTS: The SI group had a significantly higher risk of overall death compared to the EI group (adjusted hazard ratio (HR) [95% confidence interval]: 1.13 [1.10-1.15] for men and 1.18 [1.15-1.22] for women), after adjusting for various factors. This trend extended to death from the five major causes of death in South Korea (cancer, cardiovascular disease, cerebrovascular disease, pneumonia, and intentional self-harm) and from external causes, with a higher risk of death in the SI group (vs. the EI group). Further analysis stratified by economic status revealed that individuals with lower economic status faced higher risk of overall death and cause-specific mortality in both sexes, compared to those with high economic status for both health insurance types. CONCLUSION: This nationwide study found that the SI group and those with lower economic status faced higher risk of overall mortality and death from the five major causes in South Korea. These findings highlight the potential disparities in health outcomes within the NHI system. To address these gaps, strategies should target risk factors for death at the individual level and governments should incorporate such strategies into public health policy development at the population level. TRIAL REGISTRATION: This study was approved by the Institutional Review Board of Chungbuk National University Hospital (CBNUH-202211-HR-0236) and adhered to the principles of the Declaration of Helsinki (1975).

Higher high-density lipoprotein cholesterol levels increased vertebral osteoporotic fracture, but reduced hip fracture in men based on the National Health Insurance Service-National Health Screening Cohort.

BACKGROUND CONTEXT: Lipids are currently known to play an important role in bone metabolism. PURPOSE: This study aimed to investigate the effect of high-density lipoprotein cholesterol (HDL-C) on osteoporotic fractures beyond its beneficial effects on the cardiovascular system. STUDY DESIGN/SETTING: This was a retrospective, observational study that used data from the National Health Insurance Service-Health Screening cohort database. PATIENT SAMPLE: This study included 318,237 participants who were 50 years or older and with HDL-C levels of 10 to 200 mg/dL. OUTCOMES MEASURES: Physiologic measure-Diagnosis of osteoporotic fracture during the follow-up period. METHODS: The study participants were categorized into four quartiles according to baseline HDL-C levels. The Cox proportional hazards model was used to assess osteoporotic fracture risk according to HDL-C levels. RESULTS: After full adjustment and with the Q1 group as the reference group, estimates of hazard ratios (HRs; 95% confidence intervals [CIs]) for any osteoporotic fracture in men were 1.03 (0.94-1.12), 1.02 (0.93-1.11), and 1.07 (0.98-1.18) for the Q2, Q3, and Q4 groups, respectively. After classifying osteoporotic fractures according to the body location, the fully adjusted HRs for vertebral and hip fractures in the men's Q4 groups were 1.16 (1.02-1.31) and 0.74 (0.57-0.96), respectively. In women, fully adjusted HRs (95% CIs) of the female Q4 group for any osteoporotic, vertebral, and hip fractures were 1.03 (0.95-1.11), 0.96 (0.86-1.07), and 1.06 (0.80-1.41), respectively. CONCLUSION: In this study, HDL-C levels were positively associated with vertebral fractures in both men and women but inversely related to hip fractures in men. Therefore, monitoring the lipid profiles of patients with osteoporosis may be beneficial for the prevention of osteoporotic fractures.

Prediction of hospital-acquired influenza using machine learning algorithms: a comparative study.

BACKGROUND: Hospital-acquired influenza (HAI) is under-recognized despite its high morbidity and poor health outcomes. The early detection of HAI is crucial for curbing its transmission in hospital settings. AIM: This study aimed to investigate factors related to HAI, develop predictive models, and subsequently compare them to identify the best performing machine learning algorithm for predicting the occurrence of HAI. METHODS: This retrospective observational study was conducted in 2022 and included 111 HAI and 73,748 non-HAI patients from the 2011-2012 and 2019-2020 influenza seasons. General characteristics, comorbidities, vital signs, laboratory and chest X-ray results, and room information within the electronic medical record were analysed. Logistic Regression (LR), Random Forest (RF), Extreme Gradient Boosting (XGB), and Artificial Neural Network (ANN) techniques were used to construct the predictive models. Employing randomized allocation, 80% of the dataset constituted the training set, and the remaining 20% comprised the test set. The performance of the developed models was assessed using metrics such as the area under the receiver operating characteristic curve (AUC), the count of false negatives (FN), and the determination of feature importance. RESULTS: Patients with HAI demonstrated notable differences in general characteristics, comorbidities, vital signs, laboratory findings, chest X-ray result, and room status compared to non-HAI patients. Among the developed models, the RF model demonstrated the best performance taking into account both the AUC (83.3%) and the occurrence of FN (four). The most influential factors for prediction were staying in double rooms, followed by vital signs and laboratory results. CONCLUSION: This study revealed the characteristics of patients with HAI and emphasized the role of ventilation in reducing influenza incidence. These findings can aid hospitals in devising infection prevention strategies, and the application of machine learning-based predictive models especially RF can enable early intervention to mitigate the spread of influenza in healthcare settings.

Variable Selection in Bayesian Multiple Instance Regression using Shotgun Stochastic Search.

In multiple instance learning (MIL), a bag represents a sample that has a set of instances, each of which is described by a vector of explanatory variables, but the entire bag only has one label/response. Though many methods for MIL have been developed to date, few have paid attention to interpretability of models and results. The proposed Bayesian regression model stands on two levels of hierarchy, which transparently show how explanatory variables explain and instances contribute to bag responses. Moreover, two selection problems are simultaneously addressed; the instance selection to find out the instances in each bag responsible for the bag response, and the variable selection to search for the important covariates. To explore a joint discrete space of indicator variables created for selection of both explanatory variables and instances, the shotgun stochastic search algorithm is modified to fit in the MIL context. Also, the proposed model offers a natural and rigorous way to quantify uncertainty in coefficient estimation and outcome prediction, which many modern MIL applications call for. The simulation study shows the proposed regression model can select variables and instances with high performance (AUC greater than 0.86), thus predicting responses well. The proposed method is applied to the musk data for prediction of binding strengths (labels) between molecules (bags) with different conformations (instances) and target receptors. It outperforms all existing methods, and can identify variables relevant in modeling responses.

Association Between Migraine and Ischemic Cardio-Cerebrovascular Disease (CCVD) and Effects of Triptans and Ergotamine on the Risk of Ischemic CCVD in Patients with Migraine in the Korean NHIS-HEALS Cohort.

BACKGROUND AND OBJECTIVES: Triptans and ergotamine are commonly used to treat migraine, a risk factor for ischemic stroke. This study aimed to investigate the association between migraine and ischemic cardio-cerebrovascular disease (CCVD). Further analyses were performed to examine whether symptom-relieving treatment of migraine with triptans and ergotamine reduces ischemic CCVD in migraineurs. METHODS: Participants from the Korean NHIS-HEALS cohort database were divided into patients reporting headache without migraine (HA), migraineurs who received at least one prescription for triptans or ergotamine (TE), and migraineurs who were prescribed neither triptans nor ergotamine (NTNE). Ischemic CCVDs comprised ischemic cerebrovascular diseases and cardiovascular diseases. Using cox proportional hazards regression models, primary and secondary analysis for risk of ischemic CCVDs was compared. RESULTS: Among 62,272 patients diagnosed with migraine or HA, men with migraine or HA numbered 14,747 and 8935, respectively, while the numbers of women were 27,836 and 10,754, respectively. The median follow-up was 6.65 years. The overall incidence rate of CCVDs was 4728/38,590 (12.25%) in females and 3158/23,682 (13.33%) in males. Compared with the HA group, the hazard ratios (HRs) (95% CIs) of the TE and NTNE groups for ischemic CCVDs were 1.18 (1.01-1.39) and 1.39 (1.28-1.50), respectively, in males, and 1.22 (1.09-1.37) and 1.53 (1.42-1.65), respectively, in females, after full adjustment for confounding variables. Compared with the NTNE group, the HRs (95% CIs) of the TE group for ischemic CCVDs were 0.86 (0.73-0.999) in males and 0.80 (0.72-0.88) in females. CONCLUSIONS: Migraine increased the risk of ischemic CCVDs in both sexes, and migraineurs treated with triptans and ergotamine were at lower risk of ischemic CCVDs than migraineurs who did not take those medications, especially in women.

A prediction model for childhood obesity risk using the machine learning method: a panel study on Korean children.

Young children are increasingly exposed to an obesogenic environment through increased intake of processed food and decreased physical activity. Mothers' perceptions of obesity and parenting styles influence children's abilities to maintain a healthy weight. This study developed a prediction model for childhood obesity in 10-year-olds, and identify relevant risk factors using a machine learning method. Data on 1185 children and their mothers were obtained from the Korean National Panel Study. A prediction model for obesity was developed based on ten factors related to children (gender, eating habits, activity, and previous body mass index) and their mothers (education level, self-esteem, and body mass index). These factors were selected based on the least absolute shrinkage and selection operator. The prediction model was validated with an Area Under the Receiver Operator Characteristic Curve of 0.82 and an accuracy of 76%. Other than body mass index for both children and mothers, significant risk factors for childhood obesity were less physical activity among children and higher self-esteem among mothers. This study adds new evidence demonstrating that maternal self-esteem is related to children's body mass index. Future studies are needed to develop effective strategies for screening young children at risk for obesity, along with their mothers.

Association between polycythemia and risk of ischemic stroke in males based on the national health insurance service-health screening cohort.

BACKGROUND: Polycythemia, a state in which the hematocrit or hemoglobin (Hb) concentration in the peripheral blood increases, is associated with several thrombosis-related diseases, of which cerebral infarction is relatively common. This study aimed to investigate the association between ischemic stroke and polycythemia, as a potential risk factor. RESEARCH DESIGN AND METHODS: This study included men who had undergone national health checkups between 2002 and 2003; the data were extracted from the Korean National Health Insurance Service-Health Screening database. The primary outcome was the risk ischemic stroke; adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for ischemic stroke were calculated using Cox proportional hazards regression models. RESULTS: In total, 207,737 male participants aged 40-79 years were included in this study. At the baseline, 13972 (6.7%) participants met the polycythemia criteria (Hb >16.5 g/dL). During the study period, 897 and 12,440 cases of ischemic stroke occurred in the polycythemia and normocythemia (13.0 g/dL ≤ Hb ≤16.5 g/dL) groups, respectively. Compared with the normocythemia group, the polycythemia group showed an adjusted HR (95% CI) for ischemic stroke of 1.12 (1.04-1.20). CONCLUSIONS: The risk of ischemic stroke was higher in participants with polycythemia than in those with normocythemia.

Effect of metabolic health and obesity on all-cause death and CVD incidence in Korean adults: a retrospective cohort study.

This study aimed to investigate the risk of all-cause mortality and incidence of CVD according to metabolic health and body mass index (BMI) in Korean adults. This study was retrospectively designed using the National Health Insurance Service-National Health Screening Cohort data. Participants were divided into six groups according to two category of metabolic syndrome and three categories of BMI. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the composite outcome (all-cause mortality and incidence of CVDs) were estimated using multivariable Cox proportional hazards regression models. 151,706 participants aged ≥ 40 years were enrolled; median follow-up period was 9.7 years in the study. Compared to metabolically healthy normal weight, the fully adjusted HRs (95% CIs) of metabolically healthy overweight, metabolically healthy obese, metabolically unhealthy normal weight, metabolically unhealthy overweight, and metabolically unhealthy obese for composite outcome were 1.07 (1.03-1.12), 1.12 (1.07-1.17), 1.33 (1.25-1.41), 1.28 (1.22-1.34), and 1.31 (1.26-1.37), respectively, in men, and 1.10 (1.05-1.16), 1.22 (1.16-1.29), 1.34 (1.26-1.43), 1.27 (1.19-1.34), and, 1.40 (1.34-1.47), respectively, in women. High BMI and metabolic unhealthiness were associated with an increased risk on the composite of all-cause mortality and incidence of CVD in both sexes.

Metformin Use May Increase Risk of Pancreatic Cancer in Diabetic Women: An Analysis of the Korean National Health Insurance Service-National Health Screening Cohort Database.

BACKGROUND: In addition to its antidiabetic effects, metformin has pleiotropic effects, such as the inhibition of carcinogenesis. This study aimed to investigate the association between metformin use and pancreatic cancer risk in the Korean National Health Insurance Service (NHIS)-National Health Screening Cohort (HEALS). METHODS: Of the individuals in the Korean NHIS-HEALS, 29,271 men and 19,091 women were included in the final analysis after propensity score matching based on age, body mass index, and smoking status. The study population was categorized into three groups: metformin non-users with diabetes mellitus (DM), metformin users with DM, and non-diabetic users. A Cox proportional hazards regression model was used to examine the association between metformin use and pancreatic cancer. RESULTS: The median follow-up period was 12.9 years. The estimated pancreatic cancer incidence was highest in metformin users with DM, regardless of sex (P<0.001), and lowest in non-diabetic men and female metformin non-users (P=0.053). The hazard ratios (95% confidence interval) for pancreatic cancer incidence in metformin users and non-diabetic individuals were 1.116 (0.648-1.923) and 0.447 (0.259-0.771) in men and 2.769 (1.003-7.642) and 1.451 (0.529-3.984) in women, respectively, after full adjustment. CONCLUSION: Women with diabetes using metformin are at a higher risk of pancreatic cancer than women with diabetes not using metformin. Meanwhile, men with DM using metformin have a similar risk of pancreatic cancer as men with DM not using metformin.

Higher Pulse Pressure Is Associated With Increased Risk of Cardio-cerebrovascular Disease and All-Cause Mortality: A Korean National Cohort Study.

BACKGROUND: This study aimed to investigate the association of pulse pressure (PP) with the cardio-cerebrovascular disease (CCVD) risk and all-cause mortality according to blood pressure level using Korean national cohort data. METHODS: This study was retrospectively designed and based on the Korean National Health Insurance Service-National Health Screening Cohort. Participants aged 40-69 years at baseline were categorized into normal, elevated, stage 1, and stage 2 groups according to blood pressure. Each group was further classified into 5 groups separated by 10-mm Hg increments in PP. The primary composite outcome was defined as CCVDs and all-cause mortality. Cox proportional hazards regression models were adopted after stepwise adjustment for confounders to investigate the composite outcome. RESULTS: During the follow-up period (median follow-up period, 12.0 years), the primary composite outcome occurred in 18,444 (15.0%) of 122,783 men and 10,096 (11.4%) of 88,550 women. After complete adjustment for confounders, in the stage 1 hypertensive men, the hazard ratio (95% confidence intervals [CIs]) of the 31-40, 41-50, 51-60, and >60 mm Hg PP groups was 1.112 (1.013-1.221), 1.035 (0.942-1.137), 1.009 (0.907-1.123), and 1.324 (1.130-1.551) in comparison with the ≤30 mm Hg PP group. In the stage 2 hypertensive men, the HRs (95% CIs) were 1.069 (0.949-1.204), 1.059 (0.940-1.192), 1.123 (0.999-1.263), and 1.202 (1.061-1.358) compared to the ≤30 mm Hg PP group. However, these associations were not significant in women. CONCLUSIONS: Hypertensive men with an increased PP have an increased risk of CCVDs and all-cause mortality.

Recent trends in opioid prescriptions in Korea from 2002 to 2015 based on the Korean NHIS-NSC cohort.

OBJECTIVES: Opioids are prescribed to treat moderate to severe pain. We investigated recent trends in opioid (morphine, oxycodone, fentanyl, and hydromorphone) prescriptions using data from the Korean National Health Insurance Service-National Sample Cohort between 2002 and 2015. METHODS: The morphine milligram equivalent (MME) was calculated to standardize the relative potency of opioids. The number (cases) or amount (MME) of annual opioid prescriptions per 10,000 registrants was computed to analyze trends in opioid prescriptions after age standardization. Joinpoint regression analysis was conducted to calculate the annual percentage change and average annual percentage change (AAPC). RESULTS: The number (cases) of prescriptions per 10,000 registrants increased from 0.07 in 2002 to 41.23 in 2015 (AAPC, 76.0%; 95% confidence interval [CI], 61.6 to 91.7). The MME per 10,000 registrants increased from 15.06 in 2002 to 40,727.80 in 2015 (AAPC, 103.0%; 95% CI, 78.2 to 131.3). The highest AAPC of prescriptions and MME per 10,000 registrants were observed in the elderly (60-69 years) and in patients treated at general hospitals. Fentanyl prescriptions increased most rapidly among the 4 opioids. CONCLUSIONS: Consumption of opioids greatly increased in Korea over the 14-year study period.

Statin Use and Incidence of Chronic Kidney Disease in Hypercholesterolemia Patients with Normal Renal Function.

INTRODUCTION: Dyslipidemia is a known risk factor for chronic kidney disease (CKD). The effects of statins on CKD have already been studied in patients with CKD; however, data on the general population are limited. This study aimed to determine the relationship between statin use and the incidence of CKD in patients with hypercholesterolemia having normal renal function. METHODS: A total of 7,856 participants aged 40-79 years at baseline (2009-2010) were included in the final analyses. The participants were divided into statin users (n = 4,168) and statin nonusers (n = 3,668), according to the statin usage. The Cox proportional hazard regression model was used to evaluate the adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for CKD. RESULTS: The median follow-up duration was 5.8 years. A total of 543 cases of CKD (285 cases in males and 258 cases in females) occurred during the study period. The estimated cumulative incidence of CKD was significantly different between male statin nonusers and users (p < 0.001), while it was not statistically significant between female statin nonusers and users (p = 0.126). Compared with statin nonusers, the fully adjusted HRs (95% CIs) for CKD in statin users were 1.014 (0.773-1.330) in males and 1.117 (0.843-1.481) in females. CONCLUSION: Dyslipidemia is an obvious risk factor for CKD; however, statin use in patients with hypercholesterolemia having normal renal function does not demonstrate a clear relationship with the incidence of CKD.

The association between triglyceride-glucose index, cardio-cerebrovascular diseases, and death in Korean adults: A retrospective study based on the NHIS-HEALS cohort.

BACKGROUND: The triglyceride-glucose (TyG) index is a reliable indicator of insulin resistance. We aimed to investigate the TyG index in relation to cardio-cerebrovascular diseases (CCVDs and mortality. METHODS: This retrospective study included 114,603 subjects. The TyG index was categorized into four quartiles by sex: Q1, <8.249 and <8.063; Q2, 8.249‒<8.614 and 8.063‒<8.403; Q3, 8.614‒< 8.998 and 8.403‒<8.752; and Q4, ≥8.998 and ≥8.752, in men and women, respectively. To calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the primary outcomes (CCVDs and all-cause mortality) and secondary outcomes (cardiovascular diseases [CVDs], cerebrovascular diseases [CbVDs], CCVD-related deaths, or all-cause deaths), Cox proportional hazards regression models were adopted. RESULTS: Compared to Q1, the HRs (95% CIs) for the primary outcomes of Q2, Q3, and Q4 were 1.062 (0.981‒1.150), 1.110 (1.024-1.204), and 1.151 (1.058-1.252) in men and 1.099 (0.986-1.226), 1.046 (0.938-1.166), and 1.063 (0.954-1.184) in women, respectively, after adjusted for age, smoking status, drinking status, physical activity, body mass index, systolic blood pressure, low-density lipoprotein cholesterol, economic status, and anti-hypertensive medications. Fully adjusted HRs (95% CIs) for CVDs of Q2, Q3, and Q4 were 1.114 (0.969-1.282), 1.185 (1.031-1.363), and 1.232 (1.068-1.422) in men and 1.238 (1.017-1.508), 1.183 (0.971-1.440), and 1.238 (1.018-1.505) in women, respectively. The adjusted HRs (95% CIs) for ischemic CbVDs of Q2, Q3, and Q4 were 1.005 (0.850-1.187), 1.225 (1.041-1.441), and 1.232 (1.039-1.460) in men and 1.040 (0.821-1.316), 1.226 (0.981-1.532), and 1.312 (1.054-1.634) in women, respectively, while the TyG index was negatively associated with hemorrhagic CbVDs in women but not in men. The TyG index was not significantly associated with CCVD-related death or all-cause death in either sex. CONCLUSIONS: Elevated TyG index was positively associated with the primary outcomes (CCVDs and all-cause mortality) in men and predicted higher risk of CVDs and ischemic CbVDs in both sexes.

Positive association between the ratio of triglycerides to high-density lipoprotein cholesterol and diabetes incidence in Korean adults.

BACKGROUND: Insulin resistance is associated with the incidence of diabetes and cardiovascular diseases such as myocardial infarction. The ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) (TG/HDL-C ratio) is positively correlated with insulin resistance. This study aimed to investigate the relationship between the TG/HDL-C ratio and the incidence of diabetes in Korean adults. METHODS: This retrospective study used data from the National Health Insurance Service-National Health Screening Cohort. The TG/HDL-C ratio was divided into three tertiles, the T1, T2, and T3 groups, based on sex. We estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) for diabetes using multivariate Cox proportional hazards regression analyses. RESULTS: A total of 80,693 subjects aged between 40 and 79 years were enrolled. The median follow-up period was 5.9 years. The estimated cumulative incidence of diabetes in the T1, T2, and T3 groups was 5.94%, 8.23%, and 13.50%, respectively, in men and 4.12%, 4.72%, and 6.85%, respectively, in women. Compared to T1, the fully adjusted HRs (95% CIs) of the T2 and T3 groups for new-onset diabetes were 1.17 (1.06-1.30) and 1.47 (1.34-1.62), respectively, in men and 1.20 (1.02-1.42) and 1.52 (1.30-1.78), respectively, in women. CONCLUSIONS: Increased TG/HDL-C ratio was significantly associated with a higher risk of new-onset diabetes in both sexes.

The ratio of triglycerides to high-density lipoprotein cholesterol is associated with the risk of chronic kidney disease in Korean men.

Dyslipidemia is nephrotoxic and can result in the development of chronic kidney disease (CKD). The ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) (TG/HDL-C ratio) is well-correlated with insulin resistance and cardiovascular events. The aim of this study is to examine the association between the TG/HDL-C ratio and CKD in Korean adults. This study was retrospectively designed based on the National Health Insurance Service-National Health Screening cohort. Seventy three thousand and fifty-two participants aged between 40 and 79 years old at baseline (2009-2010) were included in the final analyses. The study population was classified into three tertile groups (T1 , T2 , and T3 ) according to the TG/HDL-C ratio by sex. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for CKD were calculated using Cox proportional hazard regression models. The median follow-up duration was 5.9 years. Higher tertile groups of the TG/HDL-C ratio had lower estimated glomerular filtration rates in both sexes. The cumulative incidence of CKD of T1 , T2 , and T3 was 11.89%, 12.90%, and 12.91%, respectively, in men and 10.17%, 10.61%, and 14.87%, respectively, in women (all p values < 0.001). Compared with T1 of the TG/HDL-C ratio, the HRs (95% CIs) of T2 and T3 for CKD were 1.212 (1.118-1.315) and 1.183 (1.087-1.287), respectively, in men and 0.895 (0.806-0.994) and 1.038 (0.937-1.150), respectively, in women after being fully adjusted. Higher TG/HDL-C ratios were positively associated with CKD development in men, while middle levels of TG/HDL ratios reduced the CKD incidence in women.

Metformin use in cancer survivors with diabetes reduces all-cause mortality, based on the Korean National Health Insurance Service between 2002 and 2015.

ABSTRACT: Malignant neoplasms are the leading cause of death in Korea. We aimed to examine if metformin use in cancer survivors reduces all-cause mortality. This study was retrospectively designed based on data from the Korean National Health Insurance Service-National Health Screening Cohort (HEALS) between 2002 and 2015. The Kaplan-Meier estimator and log-rank test was performed to estimate the survival function according to metformin usage (3721 metformin non-users with diabetes, 5580 metformin users with diabetes, and 24,483 non-diabetic individuals). Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality were calculated using Cox proportional hazards regression models.The median follow-up duration was 4.2 years. The HRs (95% CIs) for all-cause mortality of metformin users and the non-diabetic group were 0.762 (0.683-0.850) and 1.055 (0.966-1.152) in men and 0.805 (0.649-0.999), and 1.049 (0.873-1.260) in women, respectively, compared with metformin non-users among diabetic cancer survivors, in a fully adjusted model. After stratifying metformin users into pre- and post-diagnosis of cancers, adjusted HRs (95% CIs) of pre- and post-diagnosis metformin users for all-cause mortality were 0.948 (0.839-1.071) and 0.530 (0.452-0.621) in men and 1.163 (0.921-1.469) and 0.439 (0.323-0.596) in women, respectively.Metformin use in cancer survivors with diabetes reduced overall mortality rates. In particular, metformin use after cancer diagnosis, not before cancer diagnosis, was inversely associated with overall mortality.Active treatment with metformin for diabetic cancer survivors after cancer diagnosis can improve their survival rates.

Comparing different types of statins for secondary prevention of cardio-cerebrovascular disease from a national cohort study.

Statins have been recommended for use in atherosclerotic cardio-cerebrovascular disease (CCVD). The purpose of this study was to investigate the efficacy of five different types of statin in the secondary prevention of CCVD in patients. This study retrospectively designed and analyzed data from the National Health Insurance Service-National Health in Korea. Participants aged 40 to 69 years were categorized into five statin groups (atorvastatin, rosuvastatin, pitavastatin, simvastatin, and pravastatin). The primary composite outcome was defined as recurrence of CCVD or all causes of death. Cox proportional hazard regression models were adopted after stepwise adjustments for confounders to investigate the difference in efficacy among the different statins. Of the 755 final participants, 48 patients experienced primary composite outcomes. After adjustments, the hazard ratios (95% confidence intervals) for primary composite outcomes of atorvastatin, pitavastatin, and rosuvastatin groups were 0.956 (0.456-2.005), 1.347 (0.354-5.116), and 0.943 (0.317-2.803), respectively, when compared with the simvastatin group. There were no significant differences between the statins in efficacy for preventing recurrence of CCVD events and/or death in CCVD patients.

Metformin usage and the risk of colorectal cancer: a national cohort study.

PURPOSE: This study aimed to investigate the association between metformin usage and the risk of colorectal cancer (CRC) using data from the Korean National Health Insurance Service-National Health Screening Cohort database. METHODS: Data from the NHIS-HEALS cohort between 2002 and 2015 were longitudinally analyzed. Subjects were divided into three groups: metformin non-users with diabetes mellitus (DM), metformin users with DM, and no DM group. CRC was defined using the ICD-10 code (C18.0-C20.0) at the time of admission. Cox proportional hazard regression models were adopted after stepwise adjustment for confounders to investigate the association between metformin usage and colorectal cancer risk. RESULTS: During the follow-up period, of the total 323,430 participants, 2341 (1.33%) of the 175,495 males and 1204 (0.81%) of the 147,935 females were newly diagnosed with CRC. The estimated cumulative incidence of CRC was significantly different among the three groups based on Kaplan-Meier's survival curve (p values < 0.05 in both sexes). Compared with metformin non-users, hazard ratios (95% CIs) of metformin users and the no DM group were 0.66 (0.51-0.85) and 0.72 (0.61-0.85) in males and 0.59 (0.37-0.92) and 0.93 (0.66-1.29) in females, respectively, after being fully adjusted. CONCLUSIONS: Metformin users with diabetes appear to have a significantly lower risk of CRC compared with metformin non-users.

Metformin use in elderly population with diabetes reduced the risk of dementia in a dose-dependent manner, based on the Korean NHIS-HEALS cohort.

AIMS: The aim of this study is to investigate the association between metformin usage and dementia in an elderly Korean population. METHODS: Participants were divided into five groups: metformin non-users with diabetes mellitus (DM), metformin users with DM (low-, mid-, and high-users), and non-diabetic Individuals. Dementia was defined with primary diagnostic dementia codes according to the 10th edition of the International Classification of Diseases. To compare the incidence rate of dementia among the five groups, Kaplan-Meier estimates and log-rank test were employed. Also, to control the confounding factors, Cox proportional hazards regression models were fitted in a sequential adjustment. RESULTS: The median follow-up was 12.4 years. The overall incidence rate of dementia was 11.3% (8.4% in men and 13.9% in women). Compared with metformin non-users, hazard ratios (95% confidence intervals) of low-, mid-, and high-users and non-diabetic individuals for dementia were 0.97 (0.73-1.28), 0.77 (0.58-1.01), 0.48 (0.35-0.67), and 0.98 (0.84-1.15), respectively, in men, respectively, and 0.90 (0.65-0.98), 0.61 (0.50-0.76), 0.46 (0.36-0.58), and 0.92 (0.81-1.04), respectively, in women, after full adjustment of confounding variables. CONCLUSIONS: Metformin use in an elderly population with DM reduced dementia risk in a dose-response manner.