Hoo Jae Hann

Incidence, Prevalence, and Survival of Moyamoya Disease in Korea A Nationwide, Population-Based Study

Background and Purpose— There is a scarcity of information on the epidemiology and natural course of moyamoya disease. The aim of this study was to investigate the nationwide epidemiological features of moyamoya disease in Korea, including incidence, prevalence, and survival. Methods— We used the data from nationwide, population-based Health Insurance Review and Assessment Service claims database and Rare Intractable Disease registration program, which includes physician-certified diagnoses based on uniform criteria for moyamoya disease from 2007 to 2011. Age-specific incidence and prevalence were calculated, and survival was examined using Kaplan–Meier method. Results— The total number of patients with moyamoya disease was 8154 in 2011, with a female-to-male ratio of 1.8. The incidence from 2007 to 2011 was 1.7 to 2.3/105, and the prevalence in 2011 was 16.1/105. In total, 66.3% of patients aged 0 to 14 years underwent surgery, whereas only 21.5% in the older than 15 years age group underwent surgery. The 1- and 5-year survival rates of adult patients were 96.9% and 92.9%, respectively, and of child patients were 99.6% and 99.3%, respectively. Conclusions— The prevalence and incidence presented in this study are higher than those in previous studies. This study demonstrates that the burden of moyamoya disease in Korea is substantial.

Incidence and natural course of inflammatory bowel disease in Korea, 2006-2012: a nationwide population-based study.

Background:Although a rising trend in the incidence of inflammatory bowel disease (IBD) in Asia has been recognized, national-level, population-based studies are lacking. In this study, we investigate the epidemiological features and natural course of IBD in Korea, including incidence, bowel resection rates, survival, and cause of death. Methods:We analyzed the Rare Intractable Disease registration and Health Insurance Review and Assessment Services claims database, which include information on every patients with IBD diagnosed through uniform criteria from 2006 to 2012. Twenty-seven thousand four hundred nineteen patients with IBD newly diagnosed from 2006 to 2012 were traced to bowel resection, survival, and cause of death. Results:During study period, mean annual incidence for ulcerative colitis was 4.6 per 105 and for Crohns disease (CD) was 3.2 per 105. Bowel resection rates at 1 and 5 years for patients with ulcerative colitis were 0.8% and 2.1%, respectively, and for patients with CD were 5.0% and 9.1%, respectively. Survival of patients with CD was lower than that of the general population, whereas patients with ulcerative colitis had similar survival. In patients with CD, mortality for colon cancer, lung cancer, and gastrointestinal disease was significantly increased compared with general population. Conclusions:Incidence of IBD found in our study is the highest in East Asia. Lower bowel resection rates and higher survival compared to those of Western nations suggest that the natural course of IBD may be different between East Asia and the West.

A population-based approach indicates an overall higher patient mortality with peritoneal dialysis compared to hemodialysis in Korea

To date, only a few large-scale studies have measured the effect of dialysis modality on mortality in Asian populations. Here, we sought to compare survival between incident hemodialysis (HD) and peritoneal dialysis (PD) patients using the Korean Health Insurance Review & Assessment Service database. This enabled us to perform a population-based complete survey that included 32,280 incident dialysis patients and followed them for a median of 26.5 months. To reduce biases due to nonrandomization, we first matched 7049 patient pairs with similar propensity scores. Using the log-rank test, we found the mortality rate in PD patients was significantly higher than that in HD patients. Subsequent subgroup analyses indicated that in older patients (55 years and older), with the exception of the subgroup of patients with no comorbidities and the subgroup of patients with malignancy, PD was consistently associated with a higher mortality rate. In younger patients (under 55 years), regardless of the covariates, the survival rate of PD patients was comparable to that of HD patients. Thus, while the overall mortality rate was higher in incident PD patients, mortality rates of some incident PD and HD patients were comparable in Korea.

Risk of major cardiovascular events among incident dialysis patients: A Korean national population-based study.

BACKGROUND Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no detailed analyses of the incidences among Asian patients initiating dialysis. The aims of this study were to determine the incidence rates of major adverse cardiac and cerebrovascular events (MACCE) and to compare them between incident HD patients and PD patients. METHODS We included all patients who had started dialysis between January 1, 2005 and December 31, 2008 in Korea, and analyzed 30,279 eligible patients [22,892 hemodialysis (HD) patients and 7387 peritoneal dialysis (PD) patients] by intention-to-treat. Median follow-up was 21.5 months. RESULTS The crude incidence rates were as follows: MACCE, 182 per 1000 patient-years (PY); major adverse cardiac events (MACE), 138/1000 PY; all-cause mortality, 116/1000 PY; non-fatal acute myocardial infarction (AMI), 18/1000 PY; target vessel revascularization (TVR), 17/1000 PY; and non-fatal stroke, 60/1000 PY. When comparing all baseline covariate-adjusted relative risks between HD and PD patients, HD is overall superior to PD in terms of MACCE. Further examined by each endpoint, all-cause mortality, non-fatal AMI, and TVR occurred significantly more frequently in patients on PD than in those on HD, whereas non-fatal hemorrhagic stroke occurred significantly more frequently in patients on HD than in those on PD. CONCLUSIONS The incidence of MACCE may be different from Western dialysis patients. HD is overall superior to PD in terms of MACCE as an initial dialysis modality. Underlying mechanisms differentially affecting cardiovascular outcomes by dialysis modality remain to be further elucidated.

Oxidative stress in subsynovial connective tissue of idiopathic carpal tunnel syndrome.

Ischemic‐reperfusion injury is thought to be a cause of idiopathic carpal tunnel syndrome (CTS). The purpose of this study was to determine whether oxidative stress caused by ischemia‐reperfusion injury in subsynovial connective tissue is associated with idiopathic CTS and its symptoms. Bioptic samples of tenosynovial tissue were collected from 20 idiopathic CTS patients during surgery. Control specimens of tenosynovial tissue were collected from eight non‐CTS patients. Analysis included histological and immunohistochemical examination for the distribution of endothelial nitric oxide synthase (eNOS), nuclear factor (NF)‐κβ, and transforming growth factor (TGF)‐β RI in subsynovial connective tissues. Histological examinations showed a marked increase in fibroblast density and vascular proliferation in specimens from CTS patients. The expressions of eNOS, NF‐κβ, and TGF‐β RI in fibroblasts and vascular endothelial cells of subsynovial connective tissues of patients were significantly higher than in those of controls. A significant positive correlation was found between the subjective symptom severity of CTS, and the immunoreactivities of eNOS and NF‐κβ. This study suggests that oxidative stress in subsynovial connective tissue is related to CTS and its symptoms.

The Expression of Estrogen Receptors in the Tenosynovium of Postmenopausal Women with Idiopathic Carpal Tunnel Syndrome

The purpose of this study was to investigate estrogen receptor (ER) expression in tenosynovial tissues of postmenopausal woman with idiopathic carpal tunnel syndrome (CTS) to determine whether estrogen contributes to the pathogenesis of this condition. Biopsy samples of tenosynovial tissues were collected from 14 postmenopausal women (mean age; 57, range; 46–69 years) undergoing surgery for idiopathic CTS, and control specimens of tenosynovial tissue were collected from 6 postmenopausal women (mean age; 59, range; 48–68 years) without CTS. Histological and immunohistochemical examinations were performed to determine the distributions of ER‐α and ER‐β in tenosynovial tissues. Histological examinations showed a significant increase in fibroblast cell densities in the specimens from the carpal tunnel syndrome patients. ER‐α and ER‐β immunoreactivities were observed in fibroblasts and in the synovial lining cells of tenosynovial tissues, and these were significantly greater in patients than in controls. This study suggests that the up‐regulations of ERs in the tenosynovial tissue are associated with idiopathic CTS in postmenopausal women.

Modulation of the Levels of NMDA Receptor Subunit mRNA and the Bindings of [3H]MK-801 in Rat Brain by Chronic Infusion of Subtoxic Dose of MK-801

The effects of continuous infusion of NMDA receptor antagonist MK-801 on the modulation of NMDA receptor subunits NR1, NR2A, NR2B, and NR2C were investigated by using in situ hybridization study. Differential assembly of NMDA receptor subunits determines their functional characteristics. Continuous intracerebroventricular (i.c.v.) infusion with MK-801 (1 pmol/10 μl/h) for 7 days resulted in significant modulations in the NR1, NR2A, and NR2B mRNA levels without producing stereotypic motor syndromes. The levels of NR1 mRNA were significantly increased (9-20%) in the cerebral cortex, striatum, septum, and CA1 of hippocampus in MK-801-infused rats. The levels of NR2A mRNA were significantly decreased (11-16%) in the CA3 and dentate gyrus of hippocampus in MK-801-infused rats. In contrast to NR2A, NR2B subunit mRNA levels were increased (10-14%) in the cerebral cortex, caudate putamen, and thalamus. However, no changes of NR2C subunits in cerebellar granule layer were observed. Using quantitative ligand autoradiography, the binding of NMDA receptor ligand [3H]MK-801 was increased (12-25%) significantly in almost all brain regions except in the thalamus and cerebellum after 7 days infusion with MK-801. These results suggest that region-specific changes of NMDA receptor subunit mRNA and [3H]MK-801 binding are involved in the MK-801-infused adult rats.

An Assessment of Survival among Korean Elderly Patients Initiating Dialysis: A National Population-Based Study

Background Although the proportion of the elderly patients with incident end-stage renal disease (ESRD) patients has been increasing in Korea, there has been a lack of information on outcomes of dialysis treatment. This study aimed to assess the survival rate and to elucidate predictors for all-cause mortality among elderly Korean patients initiating dialysis. Methods We analyzed 11,301 patients (6,138 men) aged 65 years or older who had initiated dialysis from 2005 to 2008 and had followed up (median, 37.8 months; range, 3–84 months). Baseline demographics, comorbidities and mortality data were obtained using the database from the Health Insurance Review & Assessment Service. Results The unadjusted 5-year survival rate was 37.6% for all elderly dialysis patients, and the rate decreased with increasing age categories; 45.9% (65∼69), 37.5% (70∼74), 28.4% (75∼79), 24.1% (80∼84), and 13.7% (≥85 years). The multivariate Cox proportional hazard model revealed that age, sex, dialysis modality, the type of insurance, and comorbidities such as diabetes mellitus, myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, hemiparesis, liver disease, and any malignancy were independent predictors for mortality. In addition, survival rate was significantly higher in patients on hemodialysis compared to patients on peritoneal dialysis during the whole follow-up period in the intention-to-treat analysis. Conclusions Survival rate was significantly associated with age, sex, and various comorbidities in Korean elderly patients initiating dialysis. The results of our study can help to provide relevant guidance on the individualization strategy in elderly ESRD patients requiring dialysis.

Excess mortality among patients on dialysis: Comparison with the general population in Korea

Background: Although patients with end-stage renal disease (ESRD) experience excess mortality compared with the general population, the standardized mortality ratio (SMR) for Korean patients on dialysis has not yet been investigated. In this study, we evaluated the SMR among all Korean ESRD patients on maintenance dialysis in 2009 and 2010, and compared it according to age categories, sex, and dialysis modality. Methods We used data from all patients on maintenance dialysis between January 1, 2009 and December 31, 2010 in Korea using the database of the Korean Health Insurance Review and Assessment Service, and the SMR was determined by calculating of the ratio between the number of actual deaths and expected deaths. Results A total of 45,568 patients in 2009 and 48,170 patients in 2010 were included in the analysis. The overall age- and sex-adjusted SMR was 10.3 [95% confidence interval (CI), 10.0–10.6] in 2009 and 10.9 (95% CI, 10.7–11.2) in 2010. The SMR for females was much higher than for males. The SMR gradually decreased with increasing age groups. The overall SMR for maintenance hemodialysis patients was lower than that of peritoneal dialysis patients. Conclusion The SMR among Korean ESRD patients is likely to be higher than in other countries. Further evaluation is needed to attempt to improve the outcomes.

Incidence, prevalence, mortality and causes of death in Takayasu Arteritis in Korea – A nationwide, population-based study

BACKGROUND Studies investigating the epidemiology and mortality of Takayasu Arteritis (TA) are scarce. The objective of this study was to provide information regarding the epidemiology of TA, such as the incidence, prevalence, survival and cause of death in Korea. METHODS We used a national, population-based database maintained by the Rare Intractable Disease registration program and the Health Insurance Review and Assessment Service, which includes information on all TA patients, diagnosed based on uniform criteria. We also used data from Statistics Korea linked with RID database to confirm survival and cause of death. We analyzed data for the period 2008-2012. RESULTS During study period, there were 612 new patients with TA, with a female-to-male ratio of 4.3:1. The annual mean incidence was 0.24 per 105 people, and the prevalence was 2.82 per 105 people in 2012. The average annual mortality rate was 0.02 per 105 people, and the standardized mortality ratio was 3.1. The overall survival of patients with TA was 96.6%, which was significantly lower than that in the general population. Cardiovascular disease was the most common cause of death, accounting for 29 of the 64 deaths (45.3%), followed by neoplasms in 9 patients (14.1%). CONCLUSIONS The incidence and prevalence presented in this study are the highest ever reported. The survival of patients with TA was significantly lower than that of the general population, and the main cause of death was cardiovascular disease. This study reflects the need for greater awareness of TA, especially in Asian countries.