Relationship between continuity of ambulatory care and medication adherence in adult patients with type 2 diabetes in Korea: a longitudinal analysis.

BACKGROUND: Medication adherence is the most important factor in the proper management of patients with diabetes. Considering the importance of informational continuity in a changing world, it could be meaningful to improve institution-level continuity of care and its positive relationship with medication adherence. OBJECTIVES: We examined the relationship between institution-level continuity of ambulatory care and medication adherence in adult patients with type 2 diabetes receiving a new hypoglycemic prescription and sought to determine whether an improvement in medication adherence could be achieved through an ongoing relationship between the patient and the medical care institution. RESEARCH DESIGN AND SUBJECTS: This was a longitudinal study of 23,034 patients aged 20 years and older enrolled in the Korea National Health Insurance (KNHI) program and first diagnosed with type 2 diabetes in 2004. The patients were followed-up for 4 years using claims data to measure continuity of ambulatory care and adherence to oral antihyperglycemic medications. The Continuity of Care Index (COCI) was calculated on the institution level as a measure of continuity and the medication possession ratio (MPR) was used as a measure of adherence. RESULTS: After adjusting for confounding variables, the odds of being medication adherent (MPR ≥ 0.8) increased as the COCI increased [0.2≤COCI<0.4, odds ratio (OR)=2.20; 0.4≤COCI<0.6, OR=3.46; 0.6≤COCI<0.8, OR=4.76; 0.8≤COCI<1.0, OR=4.43; COCI=1.0, OR=7.24]. CONCLUSIONS: Institution-level continuity of ambulatory care was positively associated with medication adherence, which suggested that a high concentration of ambulatory care visits, whether it's a physician or an institution, could facilitate delivery of proper medical services to and increases medication adherence among patients with type 2 diabetes, and that institution-level continuity of ambulatory care could be an effective index for assessing the quality of chronic care in the fragmented health care delivery system as in Korea.

Seasonal variation in case fatality rate in Korean patients with acute myocardial infarction using the 1997-2006 Korean National Health Insurance Claims Database.

OBJECTIVE: Seasonal and monthly variation in the occurrence and case fatality rate (CFR) of acute myocardial infarction (AMI) have been reported. We examined the seasonal variation in hospital admissions and CFR in Korean patients with AMI, and analysed the influence of season on fatality risk for AMI. METHODS: We used the 10-year administrative database of the Korean National Health Insurance covering the entire population of Korea. The data included 265,935 AMI events that occurred in 228,601 patients who were admitted to hospitals across Korea from 1997-2006. RESULTS: Hospital admissions and CFR for AMI were highest in winter and lowest in summer. The fatality risk for AMI was significantly higher in spring (odds ratio [OR]: 1.06, confidence interval [CI]: 1.02-1.10), autumn (OR: 1.08, CI:1.04-1.12), and winter (OR: 1.11, CI:1.07-1.15) than in summer. Interestingly, among the summer months, the fatality risk for men was higher in August (OR: 1.10, CI: 1.01-1.19) than in June. CONCLUSIONS: Our findings support the hypothesis that AMI may be triggered by events external to atherosclerotic plaques. This seasonal evidence supports the idea that a disease forecast system may be developed using temperature information in Korea.

Regular HbA1c examination and health outcomes in adult patients with type 2 diabetes in South Korea: A retrospective cohort study.

Concerns have been raised about the effectiveness of using process-centered indicators to assess the quality of diabetes care in Korea. This study aims to examine the factors influencing the performance of regular HbA1c testing and to explore its association with health outcomes, including hospitalization and mortality. We utilized a retrospective cohort design with a 4-year follow-up period, involving 159,452 adult patients newly diagnosed with type 2 diabetes (E11 in International Classification of Diseases, 10th Edition) in 2011. We established a national population database by merging the Korea National Health Insurance (KNHI) claims database and the KNHI Qualification Database of South Korea. The proportion of diabetic patients who underwent regular HbA1c testing at least once a year in the first 3 years was determined to be 33.8%. In comparison, patients who did not receive regular tests during the same period exhibited significantly increased odds of hospitalization (diabetes/CVD/renal, OR, 1.23, 95% CI, 1.12-1.34; diabetes, OR, 1.36, 95% CI, 1.17-1.57). Additionally, this nonpatient group experienced a higher risk of mortality (OR: 1.56, 95% CI: 1.36-1.80). This study supports the positive impact of regular HbA1c testing on health outcomes for individuals with type 2 diabetes. To increase the current 33% rate of regular HbA1c testing, developing patient-customized management policies is essential. Priority should be given to diabetic patients aged 65 or older, living in rural areas, and those belonging to low-income families (medical aid).

Relationship between the use of new or used computed tomography scanners and image retake rates in South Korea.

BACKGROUND: The use of high-cost imaging has increased worldwide, contributing to increased healthcare expenditures. Without proper quality verification, the installation of used imaging equipment may lead to wasteful increases in cost due to ineffective and poor-quality imaging that requires repeat scans. PURPOSE: To examine the relationship between the use of new or used computed tomography (CT) scanners and image retake rates to evaluate the comparative quality of used and new CT scanners. MATERIAL AND METHODS: This was a retrospective cohort study of patients who first underwent CT from January 1 to June 30, 2008 (n = 258,572). Data were obtained by linking the Health Care Institution Registration Data with the Korean National Health Insurance Claims Database. Image retake rates within 30, 60, 90, and 180 days after the first CT scan were calculated, and differences in the image retake rate by new versus used CT scanners were assessed. RESULTS: After adjusting for confounders, use of a used CT scanner for the first scan increased the odds of retake within 30 days (odds ratio [OR]: 1.34, 95% confidence interval [CI]: 1.22-1.48), 60 days (OR: 1.59, 95% CI: 1.47-1.72), 90 days (OR: 1.48, 95% CI: 1.38-1.59), and 180 days (OR: 1.38, 95% CI: 1.30-1.46) compared with use of a new CT scanner. Such results were evident in scans of the spine, abdomen, chest, and face or skull base. CONCLUSION: The quality control associated with import of used CT scanners should be improved. Moreover, regular and detailed quality inspections of used CT scanners currently operating in healthcare institutions are necessary.

Comparison of Health Outcomes by Care Provider Type for Newly Diagnosed Mild Type 2 Diabetes Patients in South Korea: A Retrospective Cohort Study.

(1) Background: Although the beneficial impacts of primary care on patients' health outcomes have been reported, it is still difficult to limit patients' herd behavior in seeking tertiary or large hospital services in South Korea. The purpose of this study was to examine whether the use of primary care clinics was longitudinally beneficial for mild diabetes. (2) Methods: Using claims data from the National Health Insurance (NHI) program, this population-based retrospective cohort study compared health outcomes over a 4-year period from 2011 to 2015 by type of health care institution as a usual source of care in diabetic patients who were newly diagnosed in 2011, i.e., without any diagnosis between 2005 and 2010. (3) Results: Compared to those attending hospitals, general hospitals (GHs), or tertiary general hospitals (TGHs), patients who visited primary clinics were more likely to experience better health outcomes such as the lower risk of hospitalization and death. (4) Conclusions: These results provide additional evidence that higher-value from primary care clinics would be highly expected for early and mild type 2 diabetics. Promoting the Informed, patient-centered decision toward primary care clinics would contribute to improving the value of the healthcare delivery system.

Body mass index and all-cause mortality in patients with newly diagnosed type 2 diabetes mellitus in South Korea: a retrospective cohort study.

OBJECTIVES: The lower risk of death in overweight or obese patients, compared with normal-weight individuals, has caused confusion for patients with diabetes and healthcare providers. This study investigated the relationship between body mass index (BMI) and mortality in patients with type 2 diabetes. DESIGN: A retrospective cohort study. SETTING: We established a national population database by merging the Korea National Health Insurance (KNHI) claims database, the National Health Check-ups Database and the KNHI Qualification Database of South Korea. PARTICIPANTS: A total of 53 988 patients who were newly diagnosed with type 2 diabetes (E11 in International Classification of Diseases, 10th Edition) in 2007, had available BMI data, lacked a history of any serious comorbidity, received diabetes medication and did not die during the first 2 years were followed up for a median of 8.6 years. PRIMARY OUTCOME MEASURES: All-cause mortality. RESULTS: The mean BMI was 25.2 (SD 3.24) kg/m2, and the largest proportion of patients (29.4%) had a BMI of 25-27.4 kg/m2. Compared with a BMI of 27.5-29.9 kg/m2 (the reference), mortality risk continuously increased as BMI decreased while the BMI score was under 25 (BMI <18.5 kg/m2: adjusted HR (aHR) 2.71, 95% CI 2.24 to 3.27; BMI 18.5-20.9 kg/m2: aHR 1.94, 95% CI 1.70 to 2.22; BMI 21-22.9 kg/m2: aHR 1.51, 95% CI 1.34 to 1.70; and BMI 23-24.9 kg/m2: aHR 1.14, 95% CI 1.01 to 1.28). For patients aged ≥65 years, the inverse association was connected up to a BMI ≥30 kg/m2 group (aHR 0.76, 95% CI 0.59 to 0.98). However, the associations for men, patients aged <65 years and ever smokers resembled a reverse J curve, with a significantly greater risk of death in patients with a BMI ≥30 kg/m2. CONCLUSIONS: This study suggests that, for patients with type 2 diabetes at a normal weight, distinct approaches are needed in terms of promoting muscle mass improvement or cardiorespiratory fitness, rather than maintaining weight status. Improved early diagnosis considering the inverse association between BMI and mortality is also needed.

Relationship between oral antihyperglycemic medication adherence and hospitalization, mortality, and healthcare costs in adult ambulatory care patients with type 2 diabetes in South Korea.

BACKGROUND: Medication adherence has been identified as a major factor influencing health outcomes in patients with type 2 diabetes. OBJECTIVES: We assessed the relationship between initial adherence to oral antihyperglycemic medications and subsequent health outcomes. RESEARCH DESIGN AND SUBJECTS: This was a retrospective cohort study of 40,082 patients enrolled in Korea's national health insurance program, who were 20 years of age or older and first diagnosed with type 2 diabetes in 2004. The patients were followed up for 3 years using claims data to measure adherence to oral antihyperglycemic medications for the initial 2 years after diagnosis and to investigate hospitalization, mortality, and healthcare costs in the third year of follow-up. RESULTS: After adjusting for confounders, nonadherence in the first 2 years after prescription increased the risk for hospitalization in the third year compared with adherence over the same period [odds ratio (OR)=1.26, 95% confidence interval=1.08-1.47]. Nonadherence in at least one of the 2 years increased the risk for hospitalization compared with adherence in both years. In addition, nonadherence during both the first and second years was associated with statistically significantly greater risks for mortality during this period than was adherence (odds ratio=1.40, 95% confidence interval=1.01-1.95). Medication adherence decreased healthcare costs compared with nonadherence (ß=-0.127; P<0.001). CONCLUSIONS: Because improved medication adherence can produce better health outcomes for diabetes patients and also save national healthcare resources, government-sponsored healthcare policies to improve medication adherence among newly diagnosed diabetes patients are urgently required.

Do differences in profiling criteria bias performance measurements? Economic profiling of medical clinics under the Korea National Health Insurance program: an observational study using claims data.

BACKGROUND: With a greater emphasis on cost containment in many health care systems, it has become common to evaluate each physician's relative resource use. This study explored the major factors that influence the economic performance rankings of medical clinics in the Korea National Health Insurance (NHI) program by assessing the consistency between cost-efficiency indices constructed using different profiling criteria. METHODS: Data on medical care benefit costs for outpatient care at medical clinics nationwide were collected from the NHI claims database. We calculated eight types of cost-efficiency index with different profiling criteria for each medical clinic and investigated the agreement between the decile rankings of each index pair using the weighted kappa statistic. RESULTS: The exclusion of pharmacy cost lowered agreement between rankings to the lowest level, and differences in case-mix classification also lowered agreement considerably. CONCLUSIONS: A medical clinic may be identified as either cost-efficient or cost-inefficient, even when using the same index, depending on the profiling criteria applied. Whether a country has a single insurance or a multiple-insurer system, it is very important to have standardized profiling criteria for the consolidated management of health care costs.

Comparison of case fatality rates for acute myocardial infarction in weekday vs weekend admissions in South Korea.

BACKGROUND: According to recent reports, reduced weekend staffing in hospitals may lead to a lower intensity of management of patients with acute conditions such as acute myocardial infarction (AMI). The present study evaluated differences in the case fatality rate of Korean patients admitted with AMI on weekdays vs those admitted on weekends. METHODS AND RESULTS: The dataset was constructed from the Korea National Health Insurance Claims Database. The study population was 97,466 patients who were admitted to a hospital in Korea from 2003 to 2007 with AMI. Patients admitted on weekends had a higher 30-day fatality rate (20.1% vs 17.3%) than did those admitted on weekdays. Differences in the 30-day fatality rate were significant after adjusting for baseline characteristics and the severity of disease (odds ratio (OR), 1.21; 95% confidence interval (CI), 1.16-1.26). However, the 30-day fatality rate was insignificantly different after additional adjustment for medical or invasive management (OR 1.05; 95%CI 0.99-1.11). CONCLUSIONS: Differences in the case fatality rate of AMI patients admitted on weekdays and on weekends in Korea are caused by differences in the rate of performance of medical or invasive procedures.

Continuity of care for elderly patients with diabetes mellitus, hypertension, asthma, and chronic obstructive pulmonary disease in Korea.

We sought to assess continuity of care for elderly patients in Korea and to examine any association between continuity of care and health outcomes (hospitalization, emergency department visits, health care costs). This was a retrospective cohort study using the Korea National Health Insurance Claims Database. Elderly people, 65-84 yr of age, who were first diagnosed with diabetes mellitus (n=268,220), hypertension (n=858,927), asthma (n=129,550), or chronic obstructive pulmonary disease (COPD, n=131,512) in 2002 were followed up for four years, until 2006. The mean of the Continuity of Care Index was 0.735 for hypertension, 0.709 for diabetes mellitus, 0.700 for COPD, and 0.663 for asthma. As continuity of care increased, in all four diseases, the risks of hospitalization and emergency department visits decreased, as did health care costs. In the Korean health care system, elderly patients with greater continuity of care with health care providers had lower risks of hospital and emergency department use and lower health care costs. In conclusion, policy makers need to develop and try actively the program to improve the continuity of care in elderly patients with chronic diseases.

Body mass index and mortality in South Korean men resulting from cardiovascular disease: a Kangwha cohort study.

PURPOSE: The purpose of this study was to examine the association of body mass index (BMI) with death caused by total cardiovascular disease in a long-term follow-up study. METHODS: We followed a total of 2608 men who were 55 years or older in 1985 from March 1985 through December 2001 to investigate their mortality. The hazard ratios of mortality as the result of cardiovascular disease by BMI level were estimated with the Cox proportional hazards model, adjusting for relevant covariates. RESULTS: For the group with a BMI >/= 27 kg/m(2) compared with the reference group (BMI, 21.0-22.9), the adjusted hazard ratio of death resulting from total cardiovascular disease was 2.4 (95% confidence interval [CI], 1.5-3.9) and that of death resulting from cerebrovascular disease was 3.6 (95% CI, 2.0-6.3). Observing nonsmoking subjects only, the BMI <18.5 kg/m(2) group had a 4.6 times (95% CI, 1.8-11.8) greater risk of death attributed to total cardiovascular disease than the reference group and a 4.7 times (95% CI, 1.4-16.2) greater risk of death from cerebrovascular disease. CONCLUSION: This study defined that BMI is related to Korean male deaths caused by total cardiovascular disease. The risk of death attributed to total cardiovascular disease and cerebrovascular disease was significantly increased in the group, with a BMI >/=27 kg/m(2). In our study, in the case of nonsmokers, low BMI was shown to be related to deaths from cardiovascular disease. Such result is different from those of previous studies.

Age at menopause and cause-specific mortality in South Korean women: Kangwha Cohort Study.

OBJECTIVE: The purpose of this study was to examine the relation between age at natural menopause and all-cause and cause-specific mortality among women. METHODS: This study used the data of the Kangwha Cohort that was followed up from 1985 to 2001, in particular, for the group of 55 years or older women (n=2658). We calculated the hazard ratio of mortality by the group of age at menopause using the Cox proportional hazards model with adjustment for age, alcohol consumption, education, age at first birth, self-cognitive health level, chronic disease, marital partner, parity, age at menarche, oral contraceptive use and hypertension. RESULTS: The mean (standard deviation) age at menopause was 46.9 (4.9) years, and the median age was 48 years. After adjusting for the relevant variables, the risk of total death in the early menopause group (<40 years at menopause) was 1.32 times higher than that of the reference group (45-49 years at menopause) (95% confidence interval [CI], 1.05-1.66, p=0.02). For the early menopause group, relative to the reference group, the adjusted hazard ratios of death due to cardiovascular disease and cancer were 1.53 (95% CI, 1.00-2.39, p=0.04) and 2.01 (95% CI, 1.06-3.82, p=0.03), respectively. CONCLUSION: Through this study, the age at menopause was found to be different between Asian and Caucasian women and the association of age at menopause with death, particularly caused by cardiovascular disease and cancer, was validated. Our study is one of rare studies regarding the age at menopause of Asian women and their risk of mortality, which could be considered to be meaningful.

Association between costs and quality of acute myocardial infarction care hospitals under the Korea National Health Insurance program.

If cost reductions produce a cost-quality trade-off, healthcare policy makers need to be more circumspect about the use of cost-effective initiatives. Additional empirical evidence about the relationship between cost and quality is needed to design a value-based payment system. We examined the association between cost and quality performances for acute myocardial infarction (AMI) care at the hospital level.In 2008, this cross-sectional study examined 69 hospitals with 6599 patients hospitalized under the Korea National Health Insurance (KNHI) program. We separately estimated hospital-specific effects on cost and quality using the fixed effect models adjusting for average patient risk. The analysis examined the association between the estimated hospital effects against the treatment cost and quality. All hospitals were distributed over the 4 cost × quality quadrants rather than concentrated in only the trade-off quadrants (i.e., above-average cost and above-average quality, below-average cost and below-average quality). We found no significant trade-off between cost and quality among hospitals providing AMI care in Korea.Our results further contribute to formulating a rationale for value-based hospital-level incentive programs by supporting the necessity of different approaches depending on the quality location of a hospital in these 4 quadrants.

Greater continuity of care reduces hospital admissions in patients with hypertension: An analysis of nationwide health insurance data in Korea, 2011-2013.

OBJECTIVES: To measure the association between time-dependent COC and recurrent hospital admissions in patients with hypertension. DATA SOURCES: Korean National Health Insurance Claims Database (KNHI), between 2011 and 2013. METHODS: We used Korean National Health Insurance Claims Database (KNHI) during 2011-2013 to evaluate the association between continuity of care and hospital admission in adult patients with hypertension. We performed a recurrent event survival analysis analyzing the effect of COC on hospital admissions via Cox proportional hazard regression analysis. RESULTS: The adjusted risk of hospital admission for individuals with less COC (COC index <0.75) increased 42% (HR 1.42; 95% CI, 1.10-1.83) relative to the reference group (COC index≥0.75). Relative to individuals with a medication possession ratio (MPR) of ≥0.75, the adjusted hazard ratio for hospital admission was 2.09 (95% CI, 1.31-3.35) for those with an MPR of 0.00-0.24, 2.10 (95% CI, 1.30-3.39) for those with an MPR of 0.25-0.49, and 1.40 (95% CI, 0.82-2.39) for those with an MPR of 0.50-0.74. After 12 months, the cumulative incidence of hospital admissions was 0.42% for those with less COC and 0.25% for those with greater COC. CONCLUSIONS: Greater COC was associated with a decreased risk of hospital admission in patients with hypertension.

Sex Differences in the Treatment and Outcome of Korean Patients With Acute Myocardial Infarction Using the Korean National Health Insurance Claims Database.

Evidence showing higher acute myocardial infarction (AMI) mortality rates among female compared with male inpatients has stimulated interest in whether this disparity is the result of biological factors or differences in the provision of healthcare services. We investigated the impact of sex on in-hospital mortality rates due to AMI, and evaluated the contribution of differences in the delivery of optimal medical services for AMI.We retrospectively constructed a dataset of 85,329 new patients admitted to Korean hospitals with AMI between 2003 and 2007 from the Korea National Health Insurance Claims Database. We used the claims database to provide information about treatment after admission or death for each patient.Proportionally more female than male patients aged 65 years or older had complications; however, proportionally fewer female patients underwent invasive procedures. Female patients had a higher in-hospital mortality rate than males (21.2% vs 14.6%, odds ratio [OR] 1.58, 95% confidence interval [CI] 1.52-1.64). The probability of death within 30 days after admission remained higher for females than males after adjusting for demographic characteristics and severity (OR 1.08, 95% CI 1.04-1.13). After additionally adjusting for invasive and medical management, the probability of death within 30 days did not differ between males and females (OR 1.04, 95% CI 0.99-1.08). A similar trend was revealed by an additional analysis of patients according to younger (<65 years) and older (≥65 years) age groups.The higher in-hospital mortality rates after AMI in Korean female patients was associated with a lower procedure rate. Evidence indicating that AMI symptoms differ according to sex highlights the need for health policies and public education programs that raise awareness of sex-related differences in early AMI symptoms to increase the incidence of appropriate early treatment in females.

Regional differences in treatment frequency and case-fatality rates in korean patients with acute myocardial infarction using the Korea national health insurance claims database: findings of a large retrospective cohort study.

Issues regarding healthcare disparity continue to increase in connection with access to quality care for acute myocardial infarction (AMI), even though the case-fatality rate (CFR) continues to decrease. We explored regional variation in AMI CFRs and examined whether the variation was due to disparities in access to quality medical services for AMI patients. A dataset was constructed from the Korea National Health Insurance Claims Database to conduct a retrospective cohort study of 95,616 patients who were admitted to a hospital in Korea from 2003 to 2007 with AMI. Each patient was followed in the claims database for information about treatment after admission or death. The procedure rate decreased as the region went "down" from Seoul to the county level, whereas the AMI CFR increased as the county level as a function of proximity to the county level (30-day AMI CFRs: Seoul, 16.4%; metropolitan areas, 16.2%, cities; 18.8%, counties, 39.4%). Even after adjusting for covariates, an identical regional variation in the odds of patients receiving treatment services and dying was identified. After adjusting for invasive and medical management variables in addition to earlier covariates, the death risk in the counties remained statistically significantly higher than in Seoul; however, the degree of the difference decreased greatly and the significant differences in metropolitan areas and cities disappeared. Policy interventions are needed to increase access to quality AMI care in county-level local areas because regional differences in the AMI CFR are likely caused by differences in the performance of medical and invasive management among the regions of Korea. Additionally, a public education program to increase the awareness of early symptoms and the necessity of visiting the hospital early should be established as the first priority to improve the outcome of AMI patents, especially in county-level local areas.

Continuity of ambulatory care and health outcomes in adult patients with type 2 diabetes in Korea.

OBJECTIVES: Continuity of ambulatory care in chronic disease affects the quality of care and the efficiency of healthcare spending. We assessed the relationship between initial continuity of ambulatory care and subsequent health outcomes (hospitalization, mortality and healthcare costs). METHODS: This was a retrospective cohort study of 68,469 patients enrolled in the Korean National Health Insurance Program, who were 20 years of age or older and first diagnosed with type 2 diabetes in 2004. Patients were followed for 4 years using claims data to measure continuity of ambulatory care for the initial 3 years after first diagnosis and to investigate hospitalization, mortality, and healthcare costs in the fourth year of follow-up. RESULTS: In the group of patients with COCI<0.4, the risk of hospitalization for all causes was higher (odds ratio: 1.37, 95% CI: 1.28-1.47) and healthcare costs increased (ß=0.037, P<0.001) compared with the reference group (COCI=1.0), after adjusting for patient risk factors, such as age, gender, and comorbidity index. CONCLUSIONS: Policies that promote a continuing relationship with the same physician seem to enhance the quality of care and the efficiency of spending in the treatment of diabetic patients.

Development of peer-group-classification criteria for the comparison of cost efficiency among general hospitals under the Korean NHI program.

OBJECTIVES: To classify general hospitals into homogeneous systematic-risk groups in order to compare cost efficiency and propose peer-group-classification criteria. DATA SOURCES: Health care institution registration data and inpatient-episode-based claims data submitted by the Korea National Health Insurance system to the Health Insurance Review and Assessment Service from July 2007 to December 2009. STUDY DESIGN: Cluster analysis was performed to classify general hospitals into peer groups based on similarities in hospital characteristics, case mix complexity, and service-distribution characteristics. Classification criteria reflecting clustering were developed. To test whether the new peer groups better adjusted for differences in systematic risks among peer groups, we compared the R(2) statistics of the current and proposed peer groups according to total variations in medical costs per episode and case mix indices influencing the cost efficiency. DATA COLLECTION: A total of 1,236,471 inpatient episodes were constructed for 222 general hospitals in 2008. PRINCIPAL FINDINGS: New criteria were developed to classify general hospitals into three peer groups (large general hospitals, small and medium general hospitals treating severe cases, and small and medium general hospitals) according to size and case mix index. CONCLUSIONS: This study provides information about using peer grouping to enhance fairness in the performance assessment of health care providers.

Long-term trend in the incidence of acute myocardial infarction in Korea: 1997-2007.

BACKGROUND AND OBJECTIVES: Information about disease incidence is indispensable for the active prevention and control of acute myocardial infarction (AMI). The purpose of this study was to provide basic information for the establishment of policy related to AMI by examining the long-term trends in incidence of AMI. SUBJECTS AND METHODS: This study identified the trend in disease incidence during between 1997 and 2007 using the Korean National Health Insurance Database that includes AMI {the 10th International Classification of Disease (ICD-10) code: I21, I22, I23, I250, I251} as a primary or secondary disease. RESULTS: The attack and incidence rates for AMI in 2007 were 118.4 and 91.8 per 100,000 persons, respectively, and the rates more than doubled for the 11 years. Both rates were higher among males than females and increased more in the older age groups. Incidence cases accounted for most of the total attack cases every year; however, in recent years the proportion of relapse cases was on the rise. The case fatality rate was highest (14.5%) in 2000, and declined rapidly to 9.8% in 2007. The case fatality rate was higher among females than males and the older age groups; in particular, female patients >/=65 years of age had the highest fatality rate. CONCLUSION: This study showed that AMI has been on the rise in Korea for 11 years. Therefore, the establishment of policy for intensive control of the incidence of AMI is necessary by building a continuous monitoring and surveillance system.

[Changes in distributive equity of health insurance contribution burden].

OBJECTIVES: We analyzed the changes from 1996 to 2002 in distributive equity of the contribution burden in the Korean National Health Insurance. METHODS: The study subjects were a total of 8923 employee households and a total of 7296 self-employed households over the period from 1996 to 2002. Those were the households meeting the two criteria as completing each annual survey and having no change in the job of head of the household during that period from the raw data of the Household Income and Expenditure Survey annually conducted by the Korean National Statistical Office. The unit of analysis was a household, and this was the standard for assessing the contribution that is now applied on a monthly basis. Deciles Distribution Ratio, Contribution Concentration Curve and Contribution Concentration Index were estimated as the index of inequality. Multiple regression analysis was conducted to compare the annual ability-to-pay elasticity of the contribution to the reference year of 1996 for three groups (all households, the employee households, and the self-employed households). RESULTS: For the index of inequality, the distributive equity of contribution was improved in all three groups. In particular, the employee group experienced a substantial improvement. Using multiple regression analysis, the ability-to-pay elasticity of the contribution in the employee group significantly increased (beta = 0.232, p < 0.0001) in the year 2002 as compared to the reference year of 1996. The elasticity in the self-employed group also significantly increased (beta = 0.186, p < 0.05), although its change was smaller than that in the employee group. CONCLUSIONS: The employee group had a greater improvement for the distributive equity of the contribution burden than the self-employed group. Within the observation period, there were two important integration reforms: one was the integration of 227 self-employed societies in 1998 and the other was the integration of 139 employee societies in 2000. We expected that the equity of the contribution burden would be improved for the self-employed group since the integration reform of 1998. However, it was not improved for the self-employed group until the year 2000. This result suggests that capturing exactly the beneficiaries' ability-to-pay such as income is the precedent for distributive equity of the contribution burden, although a more sophisticated imposition standard of contribution is needed.