Byung Chul Chun

Influenza vaccine coverage rates and perceptions on vaccination in South Korea

Summary Objective This survey was performed to assess the level of influenza vaccine coverage, to understand the driving forces and barriers to vaccination and determine vaccination interventions for the following year in Korean population. Methods A national sample of 1720 community dwelling adults of age 18 and older were surveyed by individual visits during April 2005. Demographics, state of influenza vaccination, reasons for vaccination or non-vaccination and perceptions on vaccinations were asked by questionnaire. Results Influenza vaccination coverage in general population and high risk group was 34.3% and 61.3%, respectively. Predictors for vaccination were ≥65 of age, performance of regular exercise, vaccination in the previous season, experience of influenza-like illness, belief that vaccine can prevent common cold and opinion that vaccine must be taken annually. The most common reason for vaccination for both whole population and high risk groups was to prevent both influenza and common cold, while the most common reason for non-vaccination was the thought that he/she was healthy enough not to be in need for vaccination. Having more information on influenza and vaccination as well as doctors recommendation for vaccination appeared to be the most important modus operandi to encourage influenza vaccination among non-vaccinees. Conclusions Doctors recommendation was the most important factor in encouraging people to be vaccinated against influenza. Doctors should be geared up with precise information and actively encourage high risk population in order to increase vaccination coverage.

Red blood cell transfusions are associated with lower mortality in patients with severe sepsis and septic shock: a propensity-matched analysis*.

Objectives:To evaluate the effects of transfusions in patients with severe sepsis and septic shock on mortality. Design:Propensity-matched analysis of a prospective observational database (April 2005 to February 2009). Setting:Twenty-two medical and surgical intensive care units in 12 teaching hospitals in Korea. Patients:One thousand fifty-four patients with community-acquired severe sepsis and septic shock. InterventionsNone. Measurements and Main Results:Of the 1,054 patients, 407 (38.6%) received a blood transfusion. The mean pretransfusion hemoglobin level was 7.7 ± 1.2 g/dL. Transfused patients had higher 28-day and in-hospital mortality rates (32.7% vs. 17.3%; p < .001, 41.3% vs. 20.3%; p < .001, respectively) and a longer duration of hospital stay (21 [interquartile range, 10–35] vs. 13 [interquartile range, 8–24] days; p < .001), but were more severely ill at admission (lower systolic blood pressure, higher Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score at admission). In 152 pairs matched according to the propensity score depending on patient transfusion status, transfused patients had a lower risk of 7-day (9.2% vs. 27.0%; p < .001), 28-day (24.3% vs. 38.8%; p = .007), and in-hospital mortality rates (31.6% vs. 42.8%; p = .044). After adjusting for blood transfusion as a time-dependent variable in multivariable analysis, blood transfusion was independently associated with lower risk of 7-day (hazard ratio 0.42, 95% confidence interval 0.19–0.50, p = .026), 28-day (hazard ratio 0.43, 95% confidence interval 0.29–0.62, p < .001), and in-hospital mortality (hazard ratio 0.51, 95% confidence interval 0.39–0.69, p < .001). Conclusions:In this observational study of patients with community-acquired severe sepsis and septic shock, red blood cell transfusions were associated with lower risk of mortality.

A cluster of lung injury cases associated with home humidifier use: an epidemiological investigation

Background In April 2011 a tertiary hospital in Seoul, Korea reported several cases of severe respiratory distress of unknown origin in young adults. Methods To find the route of transmission, causative agent and patient risk factors of the outbreak, an investigation of the epidemic was initiated. Clinicopathological conferences led to the suspicion that the cases related to an inhalation injury. An age- and sex-matched case–control study was therefore performed to examine the inhalation exposure of the patients to various agents. Results Of the 28 confirmed cases, 18 agreed to participate. A total of 121 age- and sex-matched controls with pulmonary, allergic or obstetric disease were selected. All patients and controls completed questionnaires with questions about exposure to various inhalants. The crude ORs for patient exposure to indoor mould, humidifier use, humidifier detergent use and insecticide use were 4.4 (95% CI 1.5 to 13.1), 13.7 (95% CI 1.8 to 106.3), 47.3 (95% CI 6.1 to 369.7) and 3.9 (95% CI 1.3 to 11.7), respectively. However, when considered concurrently, indoor mould and insecticide use lost statistical significance. Moreover, humidifier use was ruled out as the cause because of a lack of biological plausibility and the weak strength of the association. This suggested that humidifier disinfectant was the cause of the outbreak. This information led the Korean government to order the removal of humidifier detergents from the market. In the years following the ban, no additional cases were detected. Conclusions Epidemiological evidence strongly suggests that the lung injury outbreak was caused by humidifier detergent use at home.

Outcome and management of spinal tuberculosis according to the severity of disease: a retrospective study of 137 adult patients at Korean teaching hospitals.

Study Design. A retrospective study examining the clinical features, management, and treatment outcome of patients with spinal tuberculosis (TB). Objective. To determine the influence of disease severity and treatment modality on outcome of patients with spinal TB. Summary of Background Data. Although anti-TB chemotherapy is now the mainstay treatment for spinal TB, it may not be applicable to all situations, especially in patients with risk of deformity, instability, and progression of neurologic deficit. Methods. In this retrospective study (1994–2003), medical records and radiographic findings of patients with spinal TB were reviewed at 7 teaching hospitals in South Korea. The duration of triple chemotherapy with isoniazid, rifampin, and ethambutol, disease severity, operative procedures, and outcome were analyzed. The outcome was assessed as both favorable and unfavorable according to predefined criteria. Results. A total of 137 patients were diagnosed with spinal TB during the study period. Twenty-one patients were lost to follow-up and excluded from analysis. The mean age was 44.07 ± 16.57 years. The most common vertebral area involved was the lumbar (44.8%). The mean number of vertebra involved was 2.25. The mean angle of kyphosis was 21.58°. Forty-seven patients (35.1%) had severe symptoms. Radical surgery was carried out in 84 (62.2%) patients. Twenty patients were treated with short-term chemotherapy, while 96 under long-term. At the end of chemotherapy, 94 patients had achieved a favorable status and 22 an unfavorable one. Statistically, there was no significant difference between the 2 groups in terms of gender, chemotherapy duration, or the severity of spinal TB; however, age (P = 0.025; odds ratio = 0.963; 95% confidence interval 0.932–0.995) and radical surgery (P = 0.043; odds ratio = 3.047; 95% confidence interval 1.038–8.942) were significantly related to a favorable outcome by logistic analysis. Conclusions. Our results showed that a younger age and radical surgery in conjunction with anti-TB chemotherapy were significant favorable prognostic factors.

Mortality and cancer incidence in Korean patients with systemic lupus erythematosus: results from the Hanyang Lupus Cohort in Seoul, Korea

The rates of mortality and cancer have not been compared between Korean systemic lupus erythematosus (SLE) patients and the general population. The objective of this study was to compare the observed mortality and cancer incidence rates of SLE patients with the expected age-, sex- and calendar-matched incidence rates of a comparable general control population. This study included 466 SLE patients who were in the Hanyang Lupus Cohort, Seoul and we excluded the males from the analyses because the number of males was too small to expect any incidence of cancer or death. We used the national female mortality rates from 1992 to 2001 as recorded by the Korean National Statistical Office as the standard mortality rates, and the Seoul Cancer Registry data as the standard cancer incidence rate. Ten of the females in our study died, giving a crude mortality rate of 596.0/100 000 person-years (PY) and a standardized mortality ratio (SMR) of 3.02. The crude cancer incidence was 179.3/100 000 PYand the standard incidence ratio was 1.04. These results demonstrate that the SMR is significantly higher in SLE patients than in the general population, whereas the incidence of cancer is the same in these two groups.

Epidemiological and genetic analysis of a sustained community-wide outbreak of hepatitis A in the Republic of Korea, 2008: A hospital-based case–control study

BACKGROUND The epidemiological shift of hepatitis A has contributed to a sustained community-wide outbreak in Korea during 2008. OBJECTIVES To assess the risk factors associated with hepatitis A virus (HAV) propagation, and to analyze the circulating genotype in the sustained community-wide outbreak. STUDY DESIGN The hospital-based case-control study was conducted in an 850-bed university hospital in Seoul from April to August, 2008. For molecular analysis of HAV isolates, a 488-bp gene fragment of the VP1 region was amplified and sequenced. RESULTS In the multivariated logistic regression model, the risk factors of HAV infection adjusted by age were contacts with hepatitis A case (OR 3.98, 95% CI: 1.36-11.66), residence with child aged <or=5 years (OR 3.43, 95% CI: 1.32-8.87), consuming uncooked lettuce (OR 3.98, 95% CI: 1.83-8.68) or carrot (OR 2.38, 95% CI: 2.38-5.09), drinking tap water (OR 3.68, 95% CI: 1.62-8.37) or portable spring water (OR 2.71, 95% CI: 1.11-6.62) supplied by water purifiers, and eating out (OR 3.87, 95% CI: 1.53-9.78). All isolates analyzed belonged to genotype IIIA. There were 42 nucleotide differences in the sequenced VP1 region among the isolates. Amino acid sequences were identical with each other. CONCLUSIONS Our study suggests that sporadically contaminated food- or water-borne sources as well as person-to-person transmission might lead a sustained community-wide HAV outbreak and pre-existing dominant genotype IA might be replaced with genotype IIIA as a major epidemic strain in Korea. Our findings urge the health authority to make public guidelines for HAV vaccination and outbreak control.

Blood Stream Infections in Patients in the Burn Intensive Care Unit

Background The study on bacteremia helps empirically select the proper antibiotics before the results of culture test about causative pathogen. The purpose of this study is to investigate causative pathogen in bloodstream infection, changing aspects based on elapsed time after burn, relationship with other sites and resistance of important causative pathogen against antibiotics through analysis on bacteria isolated from blood culture of patients hospitalized in burn intensive care unit (BICU). Materials and Methods A retrospective study was conducted targeting patients hospitalized in BICU from January 2007 to June 2011. Changes of causative pathogen in bloodstream infection based on elapsed time after injury were analyzed. We would like to examine the relationship between bloodstream infection and infection on other body parts by comparing results of cultures in burn wound site, sputum, urine and catheter tip. Antibiotics resistance patterns of Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus species, and Klebsiella pneumoniae were studied. Results A total of 2,337 burn patients were hospitalized in BICU for 54 months. Causative pathogen was cultured in blood cultures from 397 patients (17.0%). P. aeruginosa (169, 30.1%) was the most cultured and A. baumannii (107, 19.0%) and S. aureus (81, 14.4%) were followed. It was confirmed that the relative frequency of A. baumannii tended to get lower as the period got longer after injury, but the relative frequency of K. pneumoniae got higher as the period got longer after injury. With comparison without bacteremia, P. aeruginosa bacteremia showed high probability in which the same bacteria were cultured in wound site, sputum and cathether tip, and A. baumannii bacteremia and candida bacteremia had high probability in sputum, and urine and catheter tip, respectively. 95.9% of P. aeruginosa and 95.3% of A. baumannii showed the resistance against carbapenem. 96.3% of S. aureus was methicillin resistant and 36.2% of Enterococcus species were vancomycin resistant. 75.0% of K. pneumonia were extended-spectrum beta-lactamase (ESBL)-producing bacteria. Conclusions Since the highly antibiotic resistant microorganisms were isolated from the patients hospitalized in BICU during early phase, the empirical selection of antibiotics targeting these pathogens should be considered before the results of microbiologic culture test. In addition, use of empirical antifungal agent after 1 week of injury can be considered for patients who have risk factor of fungal infection.

Trends of Antibiotic Consumption in Korea According to National Reimbursement Data (2008-2012): A Population-Based Epidemiologic Study.

AbstractThis study determined the trends in the quantities and patterns of nationwide antibiotic consumption in the Republic of Korea (ROK).This nationwide descriptive epidemiological study was conducted in the ROK between 2008 and 2012. The quantities and patterns of total systemic antibiotic prescriptions were analyzed using National Health Insurance claims data collected through the Health Insurance Review and Assessment service. Data concerning systemic antibiotics were collected using measurement units of the defined daily dose (DDD) per 1000 people per day according to the Anatomical Therapeutic Chemical classification.Over the 5-year study period, the annual consumption of systemic antibiotics ranged from 21.68 to 23.12 DDD per 1000 people per day. Outpatient antibiotic use accounted for 80.9% of total consumption. A regression model with autoregressive errors showed significant increased consumption of major antibiotic subgroups, including 3rd-generation cephalosporins, carbapenems, and glycopeptides (P < 0.001). However, the antibiotic use of 1st- (P = 0.003), 2nd- (P = 0.004), and 3rd-generation (P = 0.018) cephalosporins among patients who underwent surgery under monitoring by the antimicrobial stewardship programs for perioperative prescription was significantly lower than in those who underwent surgery without monitoring programs. In time-series analysis, total antibiotic consumption demonstrated significant seasonality (P < 0.001).The consumption of broad-spectrum antibiotics was noted to have increased in the ROK from 2008 to 2012, providing a possible explanation for the changing epidemiology of multidrug resistance. Larger prospective studies are needed to investigate the impact on public health of monitoring programs of perioperative antibiotic usage.

Epidemiological and Clinical Characteristics of Community-Acquired Severe Sepsis and Septic Shock: A Prospective Observational Study in 12 University Hospitals in Korea

A prospective multicenter observational study was performed to investigate the epidemiology and outcomes of community-acquired severe sepsis and septic shock. Subjects included 1,192 adult patients admitted to the 22 participating intensive care units (ICUs) of 12 university hospitals in the Korean Sepsis Registry System from April, 2005 through February, 2009. Male accounted for 656 (55%) patients. Mean age was 65.0 ± 14.2 yr. Septic shock developed in 740 (62.1%) patients. Bacteremia was present in 422 (35.4%) patients. The 28-day and in-hospital mortality rates were 23.0% and 28.0%, respectively. Men were more likely to have comorbid illnesses and acute organ dysfunctions, and had higher mortality and clinical severity compared to women. While respiratory sources of sepsis were common in men, urinary sources were predominant in women. In the multivariate logistic regression analysis, cancer (odds ratio 1.89; 95% confidence interval 1.13-3.17), urinary tract infection (0.25; 0.13-0.46), APACHE II score (1.05; 1.02-1.09), SOFA score on day 1 (1.13; 1.06-1.21) and metabolic dysfunction (2.24, 1.45-3.45) were independent clinical factors for gender-related in-hospital mortality. This study provided epidemiological and clinical characteristics of community-acquired severe sepsis and septic shock in ICUs in Korea, and demonstrated the impact of clinical factors on gender difference in mortality.

Epidemiology of hemorrhagic fever with renal syndrome in endemic area of the Republic of Korea, 1995-1998.

We conducted an epidemiologic study to understand temporal and spatial patterns of hemorrhagic fever with renal syndrome (HFRS) in the Republic of Korea (ROK). We estimated the incidence among civilians in endemic areas through the active surveillance system during the major epidemic periods, from September to December, between 1996 and 1998. We also estimated the prevalence among Korean military personnel from 1995 to 1998. In addition, we assessed seroprevalence, subclinical infection rate, and vaccination rates in both civilians and military personnel. The incidence in civilians ranged from 2.1 to 6.6 per 100,000 person-months. The annual prevalence in the military personnel was 40-64 per 100,000 military populations, and remained generally constant throughout the study period with seasonal variation. This is the prospective epidemiologic data set on HFRS in the ROK since the inactivated Hantaan virus vaccine was licensed for use in the late 1990s. These results will be invaluable in establishing a national immunization program against HFRS.