Kyoung Hee Cho

The association between sleep duration and self-rated health in the Korean general population

STUDY OBJECTIVES Sleep duration is recognized as one of the most common issues in modern society. Self-rated health is a commonly used subjective health measure based on a single question asking individuals to rate their general health on a four- or five-point scale. However, few studies have examined the relationship between sleep duration and self-rated health. Here, we examined the association between sleep duration and poor self-rated health, using a large representative sample of the general Korean adult population. DESIGN We conducted a cross-sectional study of 15,252 participants in the Korea National Health and Nutrition Examination Survey IV (2007-2009) who were aged 19 years and older. Sleep duration was categorized as ≤ 5, 6, 7, 8, or ≥ 9 hours. The main outcome of interest was poor self-rated health (n = 3,705, 19.7%). Multiple logistic regression analysis was performed to examine the association between sleep duration and self-rated health. RESULTS We found both short (≤ 5 h) and long (≥ 9 h) sleep duration to be associated with poor self-rated health independent of sociodemographic, health risk, and health status variables. Compared with 7-h sleep duration, the multivariate odds of poor self-rated health were 1.358 times higher (95% CI 1.167-1.580) with short sleep duration and 1.322 times higher (95% CI 1.091-1.601) with long sleep duration. This association persisted in subgroup analyses of gender, body mass index, and age by gender. CONCLUSIONS In a large representative sample of the Korean general adult population, compared with sleep duration of 7 hours, we found a positive association between short and long sleep duration and poor self-rated health in Korean adults. Furthermore, the association between sleep duration and poor self-rated health was consistently present in subgroups divided by gender, age, and BMI.

A Single Measure of Cancer Burden Combining Incidence with Mortality Rates for Worldwide Application

We attempted to develop an indicator combining incidence and mortality (summary indicator of cancer burden, SMCB) and to compare the magnitudes of cancer burden by world region. The SMCB was used to measure the size of cancer burden summarizing the incidence and mortality. The incidence and mortality were divided in equivalent forms and were split. The criteria dividing the size of cancer burden were used as the maximum incidence and mortality by men and women according to the world database, and the value corresponding to 10% of each maximum was set as the cut-off value. In SMCB, the size of cancer burden was highest for men with lung cancer (SMCB=18) and for women with breast cancer (SMCB=14) in MDR (more developed regions) compared to the size of burden in LDR (lower developed regions) (lung, SMCB=11, breast, SMCB=8). For men, the size of cancer burden by region was highest in EURO (SMCB=18, lung), followed by WPRO (SMCB=16, lung), PAHO (SMCB=14, prostate), AFRO (SMCB=8, prostate) and SEARO (SMCB=7, lung). Moreover, for women, the size of cancer burden was greatest in EURO (SMCB=14, breast), followed by PAHO (SMCB=13, breast), AFRO (SMCB=11, cervix uteri), EMRO (SMCB=9, breast) or SEARO (SMCB=8, cervix uteri) and WPRO (SMCB=7, lung). The summary indicator will help to provide a priority setting for reducing cancer burden in health policy.

A Single Measure of Cancer Burden in Korea from 1999 to 2010

BACKGROUND The purpose of this study was to develop a single measure of cancer burden (SMCB), which can prioritize cancer sites by considering incidence and mortality. MATERIALS AND METHODS Incidence data from 1999 to 2010 were obtained from the Korea Central Cancer Registry. Mortality data from 1999 to 2010 were obtained from Statistics Korea. The SMCB was developed by adding incidence and mortality scores. The respective scores were given such that incidence and mortality were classified by ten ranges of equal intervals. RESULTS According to the SMCB in 2010, stomach cancer ranked 1st in males with 20 points, and colorectal cancer was 2nd with 11 points. Breast cancer and thyroid cancer were joint 1st with 11 points for females. The SMCB for females was less than that for males. The burden of stomach cancer was 1st in males from 1999-2010. The incidences of lung cancer and liver cancer decreased, whereas thyroid cancer and colon cancer increased during the period. Breast cancer and thyroid cancer burden showed tendencies to increase in females. Comparison of SMCB with disability-adjusted life years (DALY) and socioeconomic costs in 2005 showed that the top five cancer sites were similar, but there were differences in the size of the cancer burden. CONCLUSIONS The SMCB indicated that the burdens of stomach cancer in males and thyroid and breast cancers in females were large. The single measure showed an advantage, reflected as the equivalent dimensions of incidence and mortality, whereas DALY and economic costs showed tendencies to reflect premature death.

Changes in economic status of households associated with catastrophic health expenditures for cancer in South Korea.

BACKGROUND Cancer imposes significant economic challenges for individuals, families, and society. Households of cancer patients often experience income loss due to change in job status and/or excessive medical expenses. Thus, we examined whether changes in economic status for such households is affected by catastrophic health expenditures. MATERIALS AND METHODS We used the Korea Health Panel Survey (KHPS) Panel 1st-4th (2008- 2011 subjects) data and extracted records from 211 out of 5,332 households in the database for this study. To identify factors associated with catastrophic health expenditures and, in particular, to examine the relationship between change in economic status and catastrophic health expenditures, we conducted a generalized linear model analysis. RESULTS Among 211 households with cancer patients, 84 (39.8%) experienced catastrophic health expenditures, while 127 (40.2%) did not show evidence of catastrophic medical costs. If a change in economic status results from a change in job status for head of household (job loss), these households are more likely to incur catastrophic health expenditure than households who have not experienced a change in job status (odds ratios (ORs)=2.17, 2.63, respectively). A comparison between households with a newly-diagnosed patient versus households with patients having lived with cancer for one or two years, showed the longer patients had cancer, the more likely their households incurred catastrophic medical costs (OR=1.78, 1.36, respectively). CONCLUSIONS Change in economic status of households in which the cancer patient was the head of household was associated with a greater likelihood that the household would incur catastrophic health costs. It is imperative that the Korean government connect health and labor policies in order to develop economic programs to assist households with cancer patients.

A change in social activity affect cognitive function in middle-aged and older Koreans: analysis of a Korean longitudinal study on aging (2006-2012).

To examine the association between a changes in social activity and cognitive function in Koreans aged 45 years or older.

The Association between Continuity of Care and All-Cause Mortality in Patients with Newly Diagnosed Obstructive Pulmonary Disease: A Population-Based Retrospective Cohort Study, 2005-2012.

Background The disease burden is increasing for chronic obstructive pulmonary disease (COPD) due to increasing of the growth rate of prevalence and mortality. But the empirical researches are a little for COPD that studied the association between continuity of care and death and about predictors effect on mortality. Objective To investigate the association between continuity of care (COC) and chronic obstructive pulmonary disease (COPD) mortality and to identify other mortality-related factors in COPD patients. Methods We conducted a longitudinal, population-based retrospective cohort study in adult patients with COPD from 2002 to 2012 using a nationwide health insurance claims database. The study sample included individuals aged 40 years and over who developed COPD in 2005 and survived until 2006. We performed a Cox proportional hazard regression analysis with COC analyzed as a time-dependent covariate. Results Of the 3,090 participants, 60.8% died before the end of study (N = 1,879). The median years of survival for individuals with high COC (COC index≥0.75) was 3.92, and that for patients with low COC (COC index<0.75) was 2.58 in a Kaplan Meier analysis. In a multivariate, time-dependent analysis, low COC was associated with a 22% increased risk of all-cause mortality (HR, 1.22; 95% CI, 1.09–1.36). Not receiving oxygen therapy at home was associated with a 23% increased risk of all-cause mortality (HR, 1.23; 95% CI, 1.01–1.49). Moreover, the risk of all-cause mortality for individuals who admitted one time increased 38% (HR, 1.38; 95% CI, 1.21–1.59), two times was 63% (HR, 1.63; 95% CI, 1.34–1.99) and 3+ times was 96% (HR, 1.96; 95% CI, 1.63–2.36) relative to the reference group (no admission). Conclusions High COC was associated with a decreased risk of all-cause mortality. In addition, home oxygen therapy and number of hospital admissions may predict mortality in patients with COPD.

Effects of continuity of care on hospital admission in patients with type 2 diabetes: analysis of nationwide insurance data

BackgroundA system for managing chronic disease including diabetes mellitus based on primary care clinics has been used in Korea since April 2012. This system can reduce copayments for patients that are managed by a single primary-care provider and lead to improve continuity of care. The aim of this study is to determine whether there is an association between continuity of care for outpatients and hospital admission and identify the continuity index that best explains hospital admissions for patients with type 2 diabetes.MethodsWe performed a cross-sectional study using 2009 National Health Insurance Sample (NHIS) from the Health Insurance Review & Assessment Services (HIRA) of Korea. The dependent variable was hospital admission due to type 2 diabetes mellitus. Continuity of care was measured using the Usual Provider Care index (UPC), Continuity of Care index (COC), Sequential Continuity of Care index (SECON), and Integrated Continuity of Care index (ICOC).ResultsPatients with low COC scores (<0.75) were more likely to be hospitalized [odds ratio, 2.44; 95% CI, 2.17–2.75] compared with the reference group (COC ≥0.75), after adjusting for all covariates. we calculated the area under the receiver operating characteristic (AUROC) curve for each index to find which index had the greatest explanatory ability for hospital admission. The AUROC of the COC was the greatest (0.598), but the AUROC curves for the UPC (0.597), SECON (0.593), and ICOC (0.597) were similar.ConclusionsHigh continuity of care may reduce the likelihood for hospital admission. The COC had marginally more explanatory power.

Effects of continuity of care on hospital admission in patients with type 2 diabetes

BackgroundA system for managing chronic disease including diabetes mellitus based on primary care clinics has been used in Korea since April 2012. This system can reduce copayments for patients that are managed by a single primary-care provider and lead to improve continuity of care. The aim of this study is to determine whether there is an association between continuity of care for outpatients and hospital admission and identify the continuity index that best explains hospital admissions for patients with type 2 diabetes.MethodsWe performed a cross-sectional study using 2009 National Health Insurance Sample (NHIS) from the Health Insurance Review & Assessment Services (HIRA) of Korea. The dependent variable was hospital admission due to type 2 diabetes mellitus. Continuity of care was measured using the Usual Provider Care index (UPC), Continuity of Care index (COC), Sequential Continuity of Care index (SECON), and Integrated Continuity of Care index (ICOC).ResultsPatients with low COC scores (<0.75) were more likely to be hospitalized [odds ratio, 2.44; 95% CI, 2.17–2.75] compared with the reference group (COC ≥0.75), after adjusting for all covariates. we calculated the area under the receiver operating characteristic (AUROC) curve for each index to find which index had the greatest explanatory ability for hospital admission. The AUROC of the COC was the greatest (0.598), but the AUROC curves for the UPC (0.597), SECON (0.593), and ICOC (0.597) were similar.ConclusionsHigh continuity of care may reduce the likelihood for hospital admission. The COC had marginally more explanatory power.

Effect of Weekend Admission on In-Hospital Mortality in Patients with Ischemic Stroke: An Analysis of Korean Nationwide Claims Data from 2002 to 2013

BACKGROUND Studies conducted on patients with stroke in countries other than Korea demonstrated a phenomenon known as the weekend effect on 7-day, 30-day, and in-hospital mortalities. We studied patients with stroke using nationwide cohort data to determine if there was a weekend effect on mortality in a Korean population. METHODS Nationwide cohort data, collected from 2002 to 2013, were searched for all hospitalizations via the emergency department due to ischemic stroke. Coxs proportional hazards frailty model was employed, and we adjusted for all patient and hospital characteristics. RESULTS There were 8957 patients with ischemic stroke admitted via the emergency department: 2632 weekend admissions and 6325 weekday admissions. Of these, 478 (5.3%) patients were dead. After adjusting for patient and hospital characteristics, the frailty model analysis revealed significantly higher in-hospital mortality in patients admitted on weekends than in those admitted on weekdays (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.01-1.47). We obtained consistent results for the 30-day mortality findings (HR, 1.27; 95% CI, 1.04-1.55). However, no significant differences were observed in the 7-day mortality (HR, 1.13; 95% CI, .88-1.45). CONCLUSIONS Weekend admission for ischemic stroke was significantly associated with higher in-hospital and 30-day mortality after adjusting for individual characteristics and hospital factors.

Change in household income and risk for attention deficit hyperactivity disorder during childhood: A nationwide population-based cohort study

Background 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. Methods 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. Results Of 18,029 participants, 554 subjects (3.1%) were identified as having ADHD by age 10 or 11. Seven household income trajectories within three categories were found. Children living in decreasing, consistently low, and consistently mid-low income households had an increased risk of ADHD compared to children who consistently lived in the mid-high household income group. Conclusions Children who live in decreasing-income or consistently low-income households have a higher risk for ADHD. Promotion of targeted policies and priority support may help reduce ADHD in this vulnerable group.