The relationships between breastfeeding discontinuation and cesarean section delivery, and the oc... more The relationships between breastfeeding discontinuation and cesarean section delivery, and the occurrence of postpartum depression (PPD) remain unclear. Therefore, we aimed to investigate the association of breastfeeding discontinuation and cesarean section delivery with PPD during the first 6 months after delivery. Data were extracted from the Korean National Health Insurance Service-National Sample Cohort for 81,447 women who delivered during 2004-2013. PPD status was determined using the diagnosis code at outpatient or inpatient visit during the 6-month postpartum period. Breastfeeding discontinuation and cesarean section delivery were identified from prescription of lactation suppression drugs and diagnosis, respectively. Cox proportional hazards models were used to calculate adjusted hazard ratios. Of the 81,447 women, 666 (0.82%) had PPD. PPD risk was higher in women who discontinued breastfeeding than in those who continued breastfeeding (hazard ratio=3.23, P<0.0001), in w...
Childhood attention deficit hyperactivity disorder (ADHD) is reported to be more prevalent among ... more Childhood attention deficit hyperactivity disorder (ADHD) is reported to be more prevalent among socioeconomically disadvantaged groups in various countries. The effect of poverty on child development appears to depend on how long poverty lasts. The timing of poverty also seems to be important for childhood outcomes. Lifetime socioeconomic status may shape current health. Thus, we investigated the effects of household income changes from birth to 4 years on the occurrence of ADHD. Data were obtained from 18,029 participants in the Korean National Health Insurance cohort who were born in 2002 and 2003. All individuals were followed until December 2013 or the occurrence of ADHD, whichever came first. Household income trajectories were estimated using the national health insurance premium and the group-based model. Cox proportional hazard models were used to compare incidence rates between different income trajectory groups after adjustment for possible confounding risk factors. Of 18,...
This study investigated the association between employment status and depression. Data from the K... more This study investigated the association between employment status and depression. Data from the Korea Welfare Panel Study (KOWEPS) collected from 2008 to 2011 were used. A total of 7368 subjects were included in this study after exclusion of subjects with missing data and those who were self-employed or could not work. Depression was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Employment status, age, sex, region, education, marital status, income, head of household, self-rated health, smoking status, drinking habits, and the current year's and the previous year's CES-D scores were included in the model as independent variables. A generalised linear mixed-effects model for longitudinal binary data was used. Compared with those who were permanently employed, individuals who moved from permanent to precarious employment (OR 1.45, 95% CI 1.23 to 1.70) or to unemployment (OR 1.78, 95% CI 1.30 to 2.43) and from precarious employment to unemploymen...
Korea's rapidly aging population has led to a rise in the prevalence of knee osteoarthritis (... more Korea's rapidly aging population has led to a rise in the prevalence of knee osteoarthritis (which reached upwards of 21.3% in 2017) in elderly people aged 65 years and over. Most patients with knee osteoarthritis require ongoing management in the community or through primary care. Continuity of care is a desirable attribute of primary care. However, previous studies on the association between continuity of care and health outcomes have focused on specific disease populations, particularly diabetes mellitus and hypertension. The objectives of this study were to determine whether there is an association between continuity of care for outpatients with knee osteoarthritis and health outcomes. We conducted a cohort study using claims data from 2014. The study population included 131,566 patients. We measured hospital admission and medical costs during the final 3 months and the continuity of care by Most Frequent Provider Continuity (MFPC), Modified Modified Continuity Index (MMCI),...
Previous studies have examined associations between sitting time and negative health outcomes and... more Previous studies have examined associations between sitting time and negative health outcomes and mental health. However, the relationship between overall sitting time and major depressive disorder (MDD) in South Korea has not been studied. This study examined the association between MDD and overall sitting time and physical activity in South Koreans. Data from the sixth Korean National Health and Nutrition Examination Survey (KNHANES), a cross-sectional, nationally representative survey, were analyzed. Total participants were 4145 in 2014. MDD was assessed using the Patient Health Questionnaire (PHQ-9). Participants' data regarding self-reported sitting time and physical activity were analyzed via multiple logistic regression. Results showed that people who sat for 8-10 h (OR: 1.56, 95% CI: 1.15-2.11) or more than 10 h (OR: 1.71, 95% CI: 1.23-2.39) had increased risk of MDD compared to those who sat for less than 5 h a day. Subgroup analysis showed that the strongest effect of ...
There is an urgent need to reduce readmission of patients with pneumonia and improve quality of c... more There is an urgent need to reduce readmission of patients with pneumonia and improve quality of care. To assess the association between hospital resources and quality of care, we examined the effect of number of doctors per bed on 30-day readmission and investigated the combined effect of number of doctors per bed and number of beds. We used nationwide cohort sample data of health insurance claims by the National Health Insurance Service (NHIS) from 2002 to 2013. Pneumonia admissions to acute care hospitals among 7446 inpatients older than 65 were examined. We conducted a multivariate Cox proportional hazard model to analyze the association between the number of doctors per bed and 30-day readmission, as well as that of pneumonia-specific 30-day readmission with the combined effects of number of doctors per bed and number of beds. Overall, 1421 (19.1%) patients were readmitted within 30 days and 756 (11.2%) patients were readmitted for pneumonia within 30 days. Patients with pneumon...
Bone marrow-derived cell therapy has been used to treat acute myocardial infarction. However, the... more Bone marrow-derived cell therapy has been used to treat acute myocardial infarction. However, the therapeutic efficacy of this approach remains controversial. Here, we performed a systematic review and meta-analysis to evaluate short-term and long-term effectiveness of bone marrow-derived therapy. We searched eight databases (Ovid-Medline, Ovid-EMBASE, Cochrane Library, KoreaMed, KMBASE, KISS, RISS, and KisTi) up to December 2014. Demographic characteristics, clinical outcomes, and adverse events were analyzed. We identified 5534 potentially relevant studies; 405 were subjected to a full-text review. Forty-three studies with 2635 patients were included in this review. No safety issues related to cell injection were reported during follow-up. At 6 months, cell-injected patients showed modest improvements in left ventricular ejection fraction (LVEF) compared with the control group. However, there were no differences between groups at other time points. In the cardiac MRI analysis, the...
International journal for quality in health care : journal of the International Society for Quality in Health Care / ISQua, Jan 6, 2016
To determine whether patients with greater continuity of care (COC) have fewer preventable hospit... more To determine whether patients with greater continuity of care (COC) have fewer preventable hospitalizations. We conducted a cohort study using a stratified random sample of Korean National Health Insurance enrollees from 2002 to 2010. The COC index was calculated for each year post-diagnosis based on ambulatory care visits. We performed a recurrent event survival analysis via Cox proportional hazard regression analysis of preventable hospitalizations. A total of 5163 patients newly diagnosed with type 2 diabetes mellitus in 2003-6 and receiving oral hypoglycemic medication. Preventable hospitalization. Of 5163 eligible participants, 6.4% (n = 328) experienced a preventable hospitalization during the study period. The adjusted hazard ratio (HR) was 8.69 (95% CI, 2.62-28.83) for subjects with a COC score of 0.00-0.19, 7.03 (95% CI, 4.50-10.96) for those with a score of 0.20-0.39, 3.01 (95% CI, 2.06-4.40) for those with a score of 0.40-059, 4.42 (95% CI, 3.04-6.42) for those with a sco...
International journal for equity in health, Jan 8, 2016
Previous studies have shown that contextual factors and individual socioeconomic status (SES) wer... more Previous studies have shown that contextual factors and individual socioeconomic status (SES) were associated with mortality in Western developed countries. In Korea, there are few empirical studies that have evaluated the association between SES and health outcomes. We conducted cohort study to investigate the socioeconomic disparity in all-cause mortality for patients newly diagnosed with hypertension in the setting of universal health care coverage. We used stratified random sample of Korean National Health Insurance enrollees (2002-2013). We included patients newly diagnosed with hypertension (n = 28,306) from 2003-2006, who received oral medication to control their hypertension. We generated a frailty model using Cox's proportional hazard regression to assess risk factors for mortality. A total of 7,825 (27.6%) of the 28,306 eligible subjects died during the study period. Compared to high income patients from advantaged neighborhoods, the adjusted hazard ratio (HR) for high...
Private health insurance in South Korea mainly functions as supplementary and complementary healt... more Private health insurance in South Korea mainly functions as supplementary and complementary health insurance that compensates for insufficient coverage by National Health Insurance. However, full private coverage of public sector cost-sharing led to the problem of encouraging moral hazard-induced utilization, resulting in a policy change that occurred in October 2009. At that time, the Korean government introduced a minimum cost-sharing policy for indemnity health insurance. The purpose of this study was to analyze the effect of cost-sharing in private health insurance on health care utilization. We analyzed data collected from the Korean Health Panel Survey from October 2008 to December 2011. We restricted the two groups to 803 purchasers with indemnity health insurance and 7023 non-purchasers who did not obtain any private health insurance. A difference-in-difference analysis was used to evaluate the effect of the 2009 policy. After the policy change, the utilization of outpatient...
Carotid intima-media thickness (IMT) is associated with chronic inflammation, and C-reactive prot... more Carotid intima-media thickness (IMT) is associated with chronic inflammation, and C-reactive protein (CRP) level is elevated in patients with atrial fibrillation (AF). We investigated the impacts of CRP and AF on carotid atherosclerosis and ischemic stroke in patients with suspected ischemic cerebrovascular disease. One-hundred forty patients (78 males) with suspected ischemic cerebrovascular disease underwent carotid ultrasonography. The mean common carotid artery IMT, mean internal carotid artery (ICA) IMT, and plaque score were measured. Patients were divided into four groups according to the presence of AF and elevated CRP level {n=46 for AF(-)CRP(-), n=38 for AF(-)CRP(+), n=43 for AF(+)CRP(-), and n=13 for AF(+)CRP(+)}. Common carotid artery IMT was significantly higher in the AF(-)CRP(+) (0.98±0.51 mm) and AF(+)CRP(+) (0.96±0.27 mm) groups compared to the AF(-)CRP(-) (0.80±0.32 mm) and AF(+)CRP(-) (0.77±0.19 mm) groups (p=0.027). Although there was no significant difference in...
The relationships between breastfeeding discontinuation and cesarean section delivery, and the oc... more The relationships between breastfeeding discontinuation and cesarean section delivery, and the occurrence of postpartum depression (PPD) remain unclear. Therefore, we aimed to investigate the association of breastfeeding discontinuation and cesarean section delivery with PPD during the first 6 months after delivery. Data were extracted from the Korean National Health Insurance Service-National Sample Cohort for 81,447 women who delivered during 2004-2013. PPD status was determined using the diagnosis code at outpatient or inpatient visit during the 6-month postpartum period. Breastfeeding discontinuation and cesarean section delivery were identified from prescription of lactation suppression drugs and diagnosis, respectively. Cox proportional hazards models were used to calculate adjusted hazard ratios. Of the 81,447 women, 666 (0.82%) had PPD. PPD risk was higher in women who discontinued breastfeeding than in those who continued breastfeeding (hazard ratio=3.23, P<0.0001), in w...
Childhood attention deficit hyperactivity disorder (ADHD) is reported to be more prevalent among ... more Childhood attention deficit hyperactivity disorder (ADHD) is reported to be more prevalent among socioeconomically disadvantaged groups in various countries. The effect of poverty on child development appears to depend on how long poverty lasts. The timing of poverty also seems to be important for childhood outcomes. Lifetime socioeconomic status may shape current health. Thus, we investigated the effects of household income changes from birth to 4 years on the occurrence of ADHD. Data were obtained from 18,029 participants in the Korean National Health Insurance cohort who were born in 2002 and 2003. All individuals were followed until December 2013 or the occurrence of ADHD, whichever came first. Household income trajectories were estimated using the national health insurance premium and the group-based model. Cox proportional hazard models were used to compare incidence rates between different income trajectory groups after adjustment for possible confounding risk factors. Of 18,...
This study investigated the association between employment status and depression. Data from the K... more This study investigated the association between employment status and depression. Data from the Korea Welfare Panel Study (KOWEPS) collected from 2008 to 2011 were used. A total of 7368 subjects were included in this study after exclusion of subjects with missing data and those who were self-employed or could not work. Depression was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Employment status, age, sex, region, education, marital status, income, head of household, self-rated health, smoking status, drinking habits, and the current year's and the previous year's CES-D scores were included in the model as independent variables. A generalised linear mixed-effects model for longitudinal binary data was used. Compared with those who were permanently employed, individuals who moved from permanent to precarious employment (OR 1.45, 95% CI 1.23 to 1.70) or to unemployment (OR 1.78, 95% CI 1.30 to 2.43) and from precarious employment to unemploymen...
Korea's rapidly aging population has led to a rise in the prevalence of knee osteoarthritis (... more Korea's rapidly aging population has led to a rise in the prevalence of knee osteoarthritis (which reached upwards of 21.3% in 2017) in elderly people aged 65 years and over. Most patients with knee osteoarthritis require ongoing management in the community or through primary care. Continuity of care is a desirable attribute of primary care. However, previous studies on the association between continuity of care and health outcomes have focused on specific disease populations, particularly diabetes mellitus and hypertension. The objectives of this study were to determine whether there is an association between continuity of care for outpatients with knee osteoarthritis and health outcomes. We conducted a cohort study using claims data from 2014. The study population included 131,566 patients. We measured hospital admission and medical costs during the final 3 months and the continuity of care by Most Frequent Provider Continuity (MFPC), Modified Modified Continuity Index (MMCI),...
Previous studies have examined associations between sitting time and negative health outcomes and... more Previous studies have examined associations between sitting time and negative health outcomes and mental health. However, the relationship between overall sitting time and major depressive disorder (MDD) in South Korea has not been studied. This study examined the association between MDD and overall sitting time and physical activity in South Koreans. Data from the sixth Korean National Health and Nutrition Examination Survey (KNHANES), a cross-sectional, nationally representative survey, were analyzed. Total participants were 4145 in 2014. MDD was assessed using the Patient Health Questionnaire (PHQ-9). Participants' data regarding self-reported sitting time and physical activity were analyzed via multiple logistic regression. Results showed that people who sat for 8-10 h (OR: 1.56, 95% CI: 1.15-2.11) or more than 10 h (OR: 1.71, 95% CI: 1.23-2.39) had increased risk of MDD compared to those who sat for less than 5 h a day. Subgroup analysis showed that the strongest effect of ...
There is an urgent need to reduce readmission of patients with pneumonia and improve quality of c... more There is an urgent need to reduce readmission of patients with pneumonia and improve quality of care. To assess the association between hospital resources and quality of care, we examined the effect of number of doctors per bed on 30-day readmission and investigated the combined effect of number of doctors per bed and number of beds. We used nationwide cohort sample data of health insurance claims by the National Health Insurance Service (NHIS) from 2002 to 2013. Pneumonia admissions to acute care hospitals among 7446 inpatients older than 65 were examined. We conducted a multivariate Cox proportional hazard model to analyze the association between the number of doctors per bed and 30-day readmission, as well as that of pneumonia-specific 30-day readmission with the combined effects of number of doctors per bed and number of beds. Overall, 1421 (19.1%) patients were readmitted within 30 days and 756 (11.2%) patients were readmitted for pneumonia within 30 days. Patients with pneumon...
Bone marrow-derived cell therapy has been used to treat acute myocardial infarction. However, the... more Bone marrow-derived cell therapy has been used to treat acute myocardial infarction. However, the therapeutic efficacy of this approach remains controversial. Here, we performed a systematic review and meta-analysis to evaluate short-term and long-term effectiveness of bone marrow-derived therapy. We searched eight databases (Ovid-Medline, Ovid-EMBASE, Cochrane Library, KoreaMed, KMBASE, KISS, RISS, and KisTi) up to December 2014. Demographic characteristics, clinical outcomes, and adverse events were analyzed. We identified 5534 potentially relevant studies; 405 were subjected to a full-text review. Forty-three studies with 2635 patients were included in this review. No safety issues related to cell injection were reported during follow-up. At 6 months, cell-injected patients showed modest improvements in left ventricular ejection fraction (LVEF) compared with the control group. However, there were no differences between groups at other time points. In the cardiac MRI analysis, the...
International journal for quality in health care : journal of the International Society for Quality in Health Care / ISQua, Jan 6, 2016
To determine whether patients with greater continuity of care (COC) have fewer preventable hospit... more To determine whether patients with greater continuity of care (COC) have fewer preventable hospitalizations. We conducted a cohort study using a stratified random sample of Korean National Health Insurance enrollees from 2002 to 2010. The COC index was calculated for each year post-diagnosis based on ambulatory care visits. We performed a recurrent event survival analysis via Cox proportional hazard regression analysis of preventable hospitalizations. A total of 5163 patients newly diagnosed with type 2 diabetes mellitus in 2003-6 and receiving oral hypoglycemic medication. Preventable hospitalization. Of 5163 eligible participants, 6.4% (n = 328) experienced a preventable hospitalization during the study period. The adjusted hazard ratio (HR) was 8.69 (95% CI, 2.62-28.83) for subjects with a COC score of 0.00-0.19, 7.03 (95% CI, 4.50-10.96) for those with a score of 0.20-0.39, 3.01 (95% CI, 2.06-4.40) for those with a score of 0.40-059, 4.42 (95% CI, 3.04-6.42) for those with a sco...
International journal for equity in health, Jan 8, 2016
Previous studies have shown that contextual factors and individual socioeconomic status (SES) wer... more Previous studies have shown that contextual factors and individual socioeconomic status (SES) were associated with mortality in Western developed countries. In Korea, there are few empirical studies that have evaluated the association between SES and health outcomes. We conducted cohort study to investigate the socioeconomic disparity in all-cause mortality for patients newly diagnosed with hypertension in the setting of universal health care coverage. We used stratified random sample of Korean National Health Insurance enrollees (2002-2013). We included patients newly diagnosed with hypertension (n = 28,306) from 2003-2006, who received oral medication to control their hypertension. We generated a frailty model using Cox's proportional hazard regression to assess risk factors for mortality. A total of 7,825 (27.6%) of the 28,306 eligible subjects died during the study period. Compared to high income patients from advantaged neighborhoods, the adjusted hazard ratio (HR) for high...
Private health insurance in South Korea mainly functions as supplementary and complementary healt... more Private health insurance in South Korea mainly functions as supplementary and complementary health insurance that compensates for insufficient coverage by National Health Insurance. However, full private coverage of public sector cost-sharing led to the problem of encouraging moral hazard-induced utilization, resulting in a policy change that occurred in October 2009. At that time, the Korean government introduced a minimum cost-sharing policy for indemnity health insurance. The purpose of this study was to analyze the effect of cost-sharing in private health insurance on health care utilization. We analyzed data collected from the Korean Health Panel Survey from October 2008 to December 2011. We restricted the two groups to 803 purchasers with indemnity health insurance and 7023 non-purchasers who did not obtain any private health insurance. A difference-in-difference analysis was used to evaluate the effect of the 2009 policy. After the policy change, the utilization of outpatient...
Carotid intima-media thickness (IMT) is associated with chronic inflammation, and C-reactive prot... more Carotid intima-media thickness (IMT) is associated with chronic inflammation, and C-reactive protein (CRP) level is elevated in patients with atrial fibrillation (AF). We investigated the impacts of CRP and AF on carotid atherosclerosis and ischemic stroke in patients with suspected ischemic cerebrovascular disease. One-hundred forty patients (78 males) with suspected ischemic cerebrovascular disease underwent carotid ultrasonography. The mean common carotid artery IMT, mean internal carotid artery (ICA) IMT, and plaque score were measured. Patients were divided into four groups according to the presence of AF and elevated CRP level {n=46 for AF(-)CRP(-), n=38 for AF(-)CRP(+), n=43 for AF(+)CRP(-), and n=13 for AF(+)CRP(+)}. Common carotid artery IMT was significantly higher in the AF(-)CRP(+) (0.98±0.51 mm) and AF(+)CRP(+) (0.96±0.27 mm) groups compared to the AF(-)CRP(-) (0.80±0.32 mm) and AF(+)CRP(-) (0.77±0.19 mm) groups (p=0.027). Although there was no significant difference in...
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Papers by Kyoung Hee Cho