Effectiveness of COVID-19 vaccines against severe outcomes in cancer patients: Real-world evidence from self-controlled risk interval and retrospective cohort studies.

BACKGROUND: The effectiveness of COVID-19 vaccines is generally reduced in cancer patients compared to the general population. However, there are only a few studies that compare the relative risk of breakthrough infections and severe COVID-19 outcomes in fully vaccinated cancer patients versus their unvaccinated counterparts. METHODS: To assess the effectiveness of COVID-19 vaccines in cancer patients, we employed (1) a self-controlled risk interval (SCRI) design, and (2) a retrospective matched cohort design. A SCRI design was used to compare the risk of breakthrough infection in vaccinated cancer patients during the period immediately following vaccination ("control window") and the period in which immunity is achieved ("exposure windows"). The retrospective matched cohort design was used to compare the risk of severe COVID-19 outcomes between vaccinated and unvaccinated cancer patients. For both studies, data were extracted from the Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service cohort, including demographics, medical history, and vaccination records of all individuals confirmed with COVID-19. We used conditional Poisson regression to calculate the incidence rate ratio (IRR) for breakthrough infection and Cox regression to estimate the hazard ratio (HR) for severe outcomes. RESULTS: Of 14,448 cancer patients diagnosed with COVID-19 between October 2020 and December 2021, a total of 217 and 3996 cancer patients were included in the SCRI and cohort study respectively. While the risk of breakthrough infections, measured by the incidence rate in the control and exposure windows, did not show statistically significant difference in vaccinated cancer patients (IRR=0.88, 95% CI: 0.64-1.22), the risk of severe COVID-19 outcomes was significantly lower in vaccinated cancer patients compared to those unvaccinated (HR=0.27, 95% CI: 0.22-0.34). CONCLUSION: COVID-19 vaccines significantly reduce the risk of severe outcomes in cancer patients, though their efficacy against breakthrough infections is less evident.

Risk of lymphadenopathy from SARS-CoV-2 vaccination in Korea: a self-controlled case series analysis.

OBJECTIVES: To assess the risk of lymphadenopathy following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. METHODS: A self-controlled case series design was used to determine whether the risk of lymphadenopathy was higher in the 1-day to 42-day risk interval after coronavirus disease 2019 (COVID-19) vaccination compared to the control period. In addition, subgroup analyses were conducted according to baseline characteristics, time since vaccination, and sensitivity analyses adjusted for the length of the risk interval. RESULTS: The risk of developing lymphadenopathy in the risk interval (1-42 days) after COVID-19 vaccination compared to the control period was significantly increased, with a relative incidence (RI) of 1.17 (95% confidence interval [CI], 1.17 to 1.18) when the first, second, and third doses were combined. The RI was greater on the day of vaccination (1.47; 95% CI, 1.44 to 1.50). In subgroup analyses by baseline characteristics, a significantly increased risk or trend toward increased risk was observed in most subgroups except for those aged 70 years and older, with a significant increase in risk in younger individuals, those with a Charlson's comorbidity index <5, and those who received mRNA vaccines (mRNA-1273>BNT162b2). Within the 1-day to 42-day post-dose risk period, the relative risk was highest during the 1-day to 7-day post-dose period (1.59; 95% CI, 1.57 to 1.60) compared to the control period, and then the risk declined. In the sensitivity analysis, we found that the longer the risk window, the smaller the RI. CONCLUSIONS: SARS-CoV-2 vaccination is associated with a statistically significant increase in the risk of lymphadenopathy, and this risk was observed only with mRNA vaccines.

Active surveillance for adverse events of influenza vaccine safety in elderly cancer patients using self-controlled tree-temporal scan statistic analysis.

Both cancer patients and the elderly are at high risk of developing flu complications, so influenza vaccination is recommended. We aimed to evaluate potential adverse events (AEs) following influenza vaccination in elderly cancer patients using the self-controlled tree-temporal scan statistic method. From a large linked database of Korea Disease Control and Prevention Agency vaccination data and the National Health Insurance Service claims data, we identified cancer patients aged over 65 who received flu vaccines during the 2016/2017 and 2017/2018 seasons. We included all the outcomes occurring on 1-84 days post-vaccination and evaluated all temporal risk windows, which started 1-28 days and ended 2-42 days. Patients who were diagnosed with the same disease during a year prior to vaccination were excluded. We used the hierarchy of ICD-10 to identify statistically significant clustering. This study included 431,276 doses of flu vaccine. We detected signals for 1 set: other dorsopathies on 1-15 days (attributable risk 16.5 per 100,000, P = 0.017). Dorsopathy is a known AE of influenza vaccine. No statistically significant clusters were found when analyzed by flu season. Therefore, influenza vaccination is more recommended for elderly patients with cancer and weakened immune systems.

Socioeconomic burden of pneumonia due to multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa in Korea.

We aimed to estimate the socioeconomic burden of pneumonia due to multidrug-resistant Acinetobacter baumannii (MRAB) and Pseudomonas aeruginosa (MRPA). We prospectively searched for MRAB and MRPA pneumonia cases and matched them with susceptible-organism pneumonia and non-infected patients from 10 hospitals. The matching criteria were: same principal diagnosis, same surgery or intervention during hospitalisation, age, sex, and admission date within 60 days. We calculated the economic burden by using the difference in hospital costs, the difference in caregiver costs, and the sum of productivity loss from an unexpected death. We identified 108 MRAB pneumonia [MRAB-P] and 28 MRPA pneumonia [MRPA-P] cases. The estimated number of annual MRAB-P and MRPA-P cases in South Korea were 1309-2483 and 339-644, with 485-920 and 133-253 deaths, respectively. The annual socioeconomic burden of MRAB-P and MRPA-P in South Korea was $64,549,723-122,533,585 and $15,241,883-28,994,008, respectively. The results revealed that MRAB-P and MRPA-P occurred in 1648-3127 patients, resulted in 618-1173 deaths, and caused a nationwide socioeconomic burden of $79,791,606-151,527,593. Multidrug-resistant organisms (MDRO) impose a great clinical and economic burden at a national level. Therefore, controlling the spread of MDRO will be an effective measure to reduce this burden.

Big data analysis of the risk factors and rates of perioperative transfusion in immediate autologous breast reconstruction.

Patients undergoing autologous breast reconstruction (ABR) are more likely to require perioperative transfusions due to the increased intraoperative bleeding. In addition to the mastectomy site, further incisions and muscle dissection are performed at the donor sites, including the back or abdomen, increasing the possibility of transfusion. The purpose of this study was to evaluate perioperative transfusion rates and risk factors according to the type of ABR through analysis of big data. Patients who underwent total mastectomy for breast cancer between 2014 and 2019 were identified. The patients were divided into mastectomy only and immediate ABR groups. The transfusion rate was 14-fold higher in the immediate ABR group (16.1%) compared to the mastectomy only group (1.2%). The transfusion rate was highest with the pedicled transverse rectus abdominis myocutaneous flap (24.2%). Performance of the operation in medical institutions located in the provinces and coronary artery disease (CAD) were significant risk factors for the need for transfusion. The perioperative transfusion risk among patients undergoing immediate ABR was related to the flap type, location of medical institution, and CAD. Based on the higher transfusion rate in this study (16.1%) compared to previous studies, the risk factors for the need for transfusion should be determined and evidence-based guidelines should be developed to reduce the transfusion rates.

Effects of menopausal hormone therapy on cardiovascular diseases and type 2 diabetes in middle-aged postmenopausal women: analysis of the Korea National Health Insurance Service Database.

OBJECTIVE: Although menopausal hormone therapy (MHT) is the most effective treatment for menopausal symptoms, menopausal women hesitate to start MHT due to concerns about adverse events. Recently, however, it has been recommended to use it for appropriate patients who have been evaluated for baseline diseases, age, and timing of initiation. We aimed to investigate the association of MHT with cardiovascular diseases (CVDs) and type 2 diabetes among middle-aged postmenopausal women in Korea. METHODS: Data were collected from the National Health Insurance Service database in Korea from 2002 to 2016. A total of 58,060 postmenopausal women (including 8,013 [13.8%] MHT users and 50,047 [86.2%] nonusers) were included. The time-dependent Cox regression model with a 1-year latency period was used to evaluate the hazard ratio (HR) and 95% confidence interval (CI) of the associations of MHT with CVDs and type 2 diabetes outcomes. Subgroup analyses by regimen type and cumulative duration were conducted. RESULTS: In the multivariate-adjusted model, MHT was not significantly associated with CVDs (HR = 1.085, 95% CI: 0.899-1.310) or type 2 diabetes (HR = 1.104, 95% CI: 0.998-1.221). Differential effects were not observed by regimen type, cumulative duration, and years since menopause subgroups. Sensitivity analyses also did not show adverse events by MHT on CVDs and type 2 diabetes. CONCLUSIONS: Although protective effects of MHT against CVDs or type 2 diabetes were not observed among postmenopausal women who had screened underlying diseases, our results may contribute to reducing the current concerns about the use of MHT for middle-aged postmenopausal women in Korea.

Video Summary:http://links.lww.com/MENO/A807 .

Medication Adherence and Persistence of Open-Angle Glaucoma Patients in Korea: A Retrospective Study Using National Health Insurance Claims Data.

This study aimed to analyze medication adherence and persistence among open-angle glaucoma patients in Korea. A retrospective study was conducted using the Korean National Health Insurance (NHI) claims database from 2016 to 2019. Newly diagnosed open-angle glaucoma patients who were prescribed with the intraocular pressure (IOP)-lowering eyedrops were included. Adherence was measured using the medication possession ratio (MPR), and persistence was measured using the duration of therapy during the 24 month follow-up period. During the study period, 14,648 open-angle glaucoma patients were identified, and 3118 (21.3%) and 4481 patients (30.6%) were adherent to and persistent with their glaucoma treatment, respectively. The mean MPR was 48.8%, and the mean duration of therapy was 357.2 days. Logistic regression analysis showed that patients who are older, female, using prostaglandins as the index medication, and visiting secondary or tertiary hospitals were significantly associated with greater rates of adherence (odds ratio (OR) = 1.21, 1.12, 1.27, and 1.73, respectively) and persistence (OR = 1.11, 1.17, 1.16, 1.17, and 1.36, respectively) during the study period. Patients with open-angle glaucoma in Korea had substandard medication adherence and discontinued their treatment. Ophthalmologists should pay more attention to younger, male patients to improve adherence.

A Systematic Review of the National Breast Implant Registry for Application in Korea: Can We Predict "Unpredictable" Complications?

Background and Objectives: Since silicone breast implants were introduced to the market several decades ago, the safety of breast implants has remained controversial. Recently, several studies have explored breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) and breast implant illness (BII). Several countries have developed national breast implant registries to improve the safety and quality of breast implant surgery. We performed a systematic review of the current status of national breast implant registries and propose a pilot form of an appropriate breast implant registry model for Korea. Materials and Methods: The systematic review was conducted in accordance with the "preferred reporting items for systematic reviews and meta-analyses (PRISMA) pro forma". PubMed and Google Scholar databases were searched to identify all articles containing information on national breast implant registries. We limited the search to articles written in the English language from 2010 to 2020. Articles were reviewed by two independent authors. Results: A total of 63 articles related to national breast implant registries, registry principles and national breast implant registry annual reports were identified. After reviewing the literature, 25 national breast implant registry-related articles were included in the full-text synthesis. Currently, four countries, The Netherlands, Australia, Sweden, and the UK, have breast implant registries with well-formed sources for big data. Overall, similarities in data points were detected for three categories: implant-related complications, operation details, and device information. However, there were differences for each registry in terms of governance, funding, and capture rate. Conclusion: After reviewing other countries' experiences, tentative datasets for the Korean Breast Implant Registry (K-BIR) were developed. The K-BIR can improve the quality of breast implant surgery in Korea by providing datasets on overall processes and outcome measures with quality indicators and risk adjustment factors. This approach will register characteristics of patients and monitor breast implants, complications, and surgical procedures to improve the outcomes of breast implant surgery in Korea. In addition, it can be used as a track-and-trace system with automated notifications to patients in the event of a product recall or other safety concerns related to a specific type of implant.

Risk of Cataract Surgery and Age-Related Macular Degeneration After Initiation of Denosumab vs Zoledronic Acid for Osteoporosis: A Multi-Database Cohort Study.

BACKGROUND AND OBJECTIVE: There is a relative lack of head-to-head comparisons of denosumab against other osteoporosis drugs on safety. We aimed to explore ocular outcomes in patients with osteoporosis initiating denosumab vs zoledronic acid. METHODS: We conducted a cohort study using claims data (2010-15) from two large US commercial insurance databases including patients with osteoporosis who were aged 50 years or older and initiators of denosumab or zoledronic acid. The primary outcomes were (1) receipt of cataract surgery and development of (2) wet age-related macular degeneration and (3) dry age-related macular degeneration within 365 days after initiation of denosumab vs zoledronic acid. Propensity score fine stratification and weighting were used to control for potential confounding, and we calculated the incidence rate and hazard ratio for each outcome in the cohorts. The estimates from the two databases were combined with a fixed-effects model meta-analysis. RESULTS: The study cohort included 50,821 denosumab and 67,471 zoledronic acid initiators. In the propensity score-weighted analysis, compared to zoledronic acid use, denosumab was associated with a modestly decreased risk of undergoing cataract surgery (hazard ratio 0.91; 95% confidence interval 0.85-0.98) but not with the risk of wet age-related macular degeneration (hazard ratio 1.29; 95% confidence interval 0.99-1.70) or dry age-related macular degeneration (hazard ratio 1.03; 95% confidence interval 0.98-1.09). CONCLUSIONS: In this large population-based cohort study of 118,292 patients with osteoporosis, initiation of denosumab was associated with a modestly decreased risk of cataract surgery vs zoledronic acid. The risk of age-related macular degeneration was similar between the two drugs.

Healthcare resource use and costs of diabetic macular oedema for patients with antivascular endothelial growth factor versus a dexamethasone intravitreal implant in Korea: a population-based study.

OBJECTIVES: To estimate the costs and healthcare resources of patients with diabetic macular oedema (DME) who received intravitreal antivascular endothelial growth factor (anti-VEGF) agents or a dexamethasone intravitreal implant (DEX-implant) in Korea. DESIGN: Retrospective cohort study. SETTING: The Korean National Health Insurance claim data from 1 January 2015 to 30 June 2017 were retrieved from the Health Insurance Review and Assessment Service. PARTICIPANTS: Adult patients with DME who were diagnosed with diabetic retinopathy or DME and received ranibizumab, aflibercept or a DEX-implant in conjunction with intravitreal injection were included. Patients whose primary diagnoses were age-related macular degeneration or retinal vein occlusion were excluded. MAIN OUTCOME MEASURES: Healthcare resource utilisation and costs related to DME in the 12-month postindex period. RESULTS: During the study period, 182 patients and 414 patients were identified in the anti-VEGF and DEX-implant groups, respectively, and there was no significant difference in the demographic characteristics between the two groups. The outpatient eye care-related medical costs were US$3002.33 for the anti-VEGF group vs US$2250.35 for the DEX-implant group (p<0.0001). After adjusting the relevant covariates based on the generalised linear model, the estimated outpatient eye care-related medical costs were 33% higher in the anti-VEGF group than in the DEX-implant group (p<0.0001, 95% CI 22% to 45%). The utilisation pattern of the two groups showed no significant difference except for the number of intravitreal injections, which was higher in the anti-VEGF group (2.69±2.29) than in the DEX-implant group (2.09±1.37, p<0.001). CONCLUSION: The average annual eye-related medical cost of the DEX-implant group was significantly lower than that of the anti-VEGF group during the study period, which was mainly due to decreased utilisation of eye care-related injections. Further long-term studies are needed.

Effectiveness and Safety of Clopidogrel Co-administered With Statins and Proton Pump Inhibitors: A Korean National Health Insurance Database Study.

Simultaneous competition for cytochrome P450 (CYP) 2C19 and CYP3A4 might diminish clopidogrel's antiplatelet effect by impacting its metabolic activation. This pharmacoepidemiologic study investigated whether proton pump inhibitors (PPIs) and CYP3A4-metabolized statins individually and jointly increase thrombotic events by attenuating clopidogrel's effectiveness. From Korean nationwide claims data (2007-2015), we selected 59,233 patients who initiated clopidogrel and statins after coronary stenting and compared thrombotic risks by PPI or CYP3A4-metabolized statin use or both. PPIs were associated with increased thrombotic risks (hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.12-1.45), unlike CYP3A4-metabolized statins (HR 1.03, 95% CI 0.98-1.07). PPIs with high CYP2C19-inhibitory potential were more relevant than those with low potential (HR 1.28, 95% CI 1.02-1.61). Joint effects of PPIs and CYP3A4-metabolized statins were nonsignificant (relative excess risk due to interaction -0.14, 95% CI -0.34 to 0.07). Concurrent PPIs were associated with increased thrombotic risks in patients receiving clopidogrel and statins; CYP3A4-metabolized statins did not exacerbate PPI-associated risks.

Prevalence of extraintestinal manifestations in Korean inflammatory bowel disease patients.

BACKGROUND: The prevalence of inflammatory bowel disease (IBD) in South Korea is increasing. Although extraintestinal manifestations (EIMs) are an important factor in the clinical outcomes of IBD patients, EIMs have not yet been investigated in Korea. Thus, we conducted a cross-sectional study to assess the prevalence of EIMs in Korean IBD patients. METHODS: The 2014 claims data from the National Health Insurance System (NHIS) of Korea were used. IBD patients were identified by codes for Crohn disease (CD) and ulcerative colitis (UC) in the NHIS registration system for rare or intractable diseases. International Classification of Diseases, Tenth Edition codes were used to identify EIM cases. To estimate the prevalence of EIMs in the general population of Korea, we used national sample data. Standardized prevalence ratios (SPRs) were calculated to compare the prevalence rates of EIMs among IBD patients to those among the general population of Korea. RESULTS: A total of 13,925 CD patients and 29,356 UC patients were identified. CD and UC patients were different in terms of demographics and utilization of medication. Among the 17 EIMs investigated, pyoderma gangrenosum, osteomalacia, Sweet syndrome, and scleritis were observed in very few patients. The SPRs were greater than 1 for all EIMs. Aphthous stomatitis, rheumatoid arthritis, and osteoporosis were highly prevalent in both CD and UC patients, but the SPRs of the EIMs were not high. CONCLUSION: The study confirmed that EIMs are more prevalent among IBD patients than among the general population of Korea. The prevalence of EIMs in IBD patients suggests the need for greater attention and effort in clinical practice.

Serum 25-hydroxyvitamin D and Age-Related Cataract.

PURPOSE: Cataract and insufficient vitamin D intake are both increasing worldwide concerns, yet little is known about the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and age-related cataract. We performed this study to determine the association between serum 25(OH)D levels and age-related cataract in adults. METHODS: Study participants comprised 16,086 adults aged 40 years or older who had never been diagnosed with or undergone surgery for cataract using Korean National Health and Nutrition Examination Survey data from 2008 to 2012. Participants were assessed to have cataract when diagnosed with cortical, nuclear, anterior subcapsular, posterior subcapsular, or mixed cataract. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the magnitude and significance of the association between serum 25(OH)D levels and cataract in multivariable logistic regression models. RESULTS: The OR for nuclear cataract with the highest quintile of serum 25(OH)D levels was 0.86 (95% CI 0.75-0.99) compared to the lowest quintile. A linear trend across quintiles was significant. Natural log-transformed serum 25(OH)D levels were also significantly associated with nuclear cataract (OR 0.84, 95% CI 0.75-0.95). The opulation-attributable fraction of nuclear cataract due to serum 25(OH)D insufficiency (<30 ng/mL) was 8.8% (p = 0.048). CONCLUSIONS: Serum 25(OH)D levels were inversely associated with the risk of nuclear cataract. Prospective studies investigating the effects of serum 25(OH)D levels on the development of nuclear cataract are needed to confirm our findings.

AGE, SEX, AND TIME-SPECIFIC TRENDS IN SURGICAL APPROACHES FOR RHEGMATOGENOUS RETINAL DETACHMENT: A Nationwide, Population-Based Study Using the National Claim Registry.

PURPOSE: To investigate the primary surgical approach for rhegmatogenous retinal detachment (RRD) according to age group, sex, and year in Korea. METHODS: We retrospectively identified patients from the national claims database who underwent primary surgery for RRD from 2007 to 2011 using the diagnostic code and surgical codes for RRD. Patients were categorized into three groups according to surgical treatment; scleral buckling, vitrectomy, and combined operation. We analyzed the frequency and proportion of primary surgical approach for RRD according to age group, sex, and year. RESULTS: Of 24,928 RRD patients, 11,372 (45.6%) patients underwent scleral buckling, 10,583 (42.5%) patients underwent vitrectomy, and 2,973 (11.9%) underwent a combined operation. Regression analysis showed that relative proportion of surgical approach had linear relationship with age; the percentage of patients undergoing vitrectomy increased by an average of 7.55% every 10 years (P < 0.001). This age-related trend was observed for both sexes. Scleral buckling tended to be preferred in younger patients (<45 years) and vitrectomy in older patients (≥45 years). Men tended to undergo vitrectomy significantly more than women in patients aged 15 years to 34 years. There was no consistent trend over time in the primary surgical approach during the study period. CONCLUSION: Age and sex of RRD patients influence the selection of primary surgical approaches. Young patients tend to undergo scleral buckling, whereas older patients tend to receive vitrectomy. Among young patients, men are more likely to undergo vitrectomy than women. No discernible trend over time was observed in the surgical approach over the 5-year study period.

Brief Report: Utilization of the First Biosimilar Infliximab Since Its Approval in South Korea.

OBJECTIVE: The US Food and Drug Administration is considering an application for a biosimilar version of infliximab, which has been available in South Korea since November 2012. The aim of the present study was to examine the utilization patterns of both branded and biosimilar infliximab and other tumor necrosis factor (TNF) inhibitors in South Korea before and after the introduction of this biosimilar infliximab. METHODS: Using claims data from April 2009 to March 2014 from the Korean Health Insurance Review and Assessment Service database, which includes the entire South Korean population, the number of claims for biosimilar infliximab was assessed. A segmented linear regression model was used to examine the utilization patterns of infliximab (the branded and biosimilar versions) and other TNF inhibitors (adalimumab and etanercept) before and after the introduction of the biosimilar infliximab. RESULTS: In total, 20,976 TNF inhibitor users were identified from the South Korean claims database, including 983 with a prescription claim for biosimilar infliximab. Among all of the claims for any version of infliximab, the proportion of biosimilar infliximab claims increased to 19% through March 2014. Before November 2012, each month there were 33 (95% confidence interval [95% CI] 32, 35) more infliximab claims, 44 (95% CI 40, 48) more etanercept claims, and 50 (95% CI 47, 53) more adalimumab claims. After November 2012, there were significant changes in the slopes for trend in usage, with additional increases in the use of branded and biosimilar infliximab (9 more claims per month, 95% CI 2, 17) and decreases in the use of etanercept (-52 claims per month, 95% CI -66, -38) and adalimumab (-21 claims per month, 95% CI -35, -6). CONCLUSION: During the first 15 months since its introduction in South Korea, one-fifth of all infliximab claims were for the biosimilar version. Introduction of biosimilar infliximab may affect the use of other TNF inhibitors, and the magnitude of change in usage will likely differ in other countries.

Risk and Risk Periods for Stroke and Acute Myocardial Infarction in Patients with Central Retinal Artery Occlusion.

PURPOSE: To investigate the risk of stroke and acute myocardial infarction (AMI) in patients with incident central retinal artery occlusion (CRAO). DESIGN: A self-controlled case series (SCCS) study. PARTICIPANTS: Patients with incident CRAO from the entire Korean population of 48 million individuals. METHODS: We used the Korean national claim database (2007-2011) for analyses. After identifying patients with incident CRAO, the relative incidence rate ratios (IRRs) for stroke and AMI in risk periods were measured in these patients using a SCCS method. MAIN OUTCOME MEASURES: The IRRs of stroke and AMI by risk periods. RESULTS: Of 1655 patients with incident CRAO in 2009-2010, 165 had stroke/AMI (ischemic stroke in 139, hemorrhagic stroke in 13, and AMI in 15) in the observation period spanning 365 days before and after the occurrence of CRAO. The IRR of stroke/AMI 1 to 30 days after CRAO occurrence significantly increased (14.0; 95% confidence interval [CI], 8.90-22.00); the IRR peaked during the 1 to 7 days after CRAO occurrence (44.51; 95% CI, 27.07-73.20), and the increased risk was present for the first 30 days. The IRR of stroke/AMI also significantly increased 1 to 30 days (6.82; 95% CI, 4.01-11.60) and 31 to 90 days (2.86; 95% CI, 1.66-4.93) before CRAO occurrence. Subanalysis for only ischemic stroke showed similar, magnified IRRs in the risk periods compared with all events. The IRRs were not significantly different between sexes or age groups (<65 vs. ≥65 years). CONCLUSIONS: Patients with incident CRAO are at increased risk of ischemic stroke just after CRAO occurrence, and the risk is particularly increased during the first week immediately after the CRAO occurrence. The results suggest that patients with incident CRAO require immediate neurologic evaluation and preventive treatment to reduce mortality and morbidity.

A comparison of risperidone and haloperidol for the risk of ischemic stroke in the elderly: a propensity score-matched cohort analysis.

OBJECTIVE: With an increase in antipsychotic use in the elderly, the safety profile of antipsychotics has been emphasized. Strong concerns have been raised about whether the risk of ischemic stroke differs between risperidone and haloperidol. This study compared the risk of ischemic stroke between elderly patients taking risperidone and haloperidol. METHOD: We conducted a retrospective cohort study using the Korea Health Insurance Review and Assessment Service database, applying a propensity-matched analysis. The cohort consisted of elderly patients who were newly prescribed haloperidol or risperidone between January 1, 2006 and December 31, 2009. Patients with prior cerebrovascular diseases (ICD-10, I60-I69), transient ischemic attack (ICD-10, G45), or cerebral tumors (ICD-10, C31) during 365 days prior to the initiation date were excluded. The study subjects were selected by propensity score matching. The outcome was defined as the first hospitalization for ischemic stroke (ICD-10, I63). Cox regression models were used to estimate the hazard ratio (HR) and 95% confidence intervals (95% CI) for ischemic stroke with haloperidol compared with risperidone use. RESULTS: A total of 14,103 patients were included in the propensity-matched cohort for each drug. Overall, the incidence rate was higher for haloperidol users compared to the risperidone users (6.43 per 1000 person-years vs. 2.88 per 1000 person-years). A substantially increased risk was observed in haloperidol users (adjusted HR = 2.02, 95% CI, 1.12-3.62). CONCLUSIONS: The evidence showed that haloperidol should be prescribed in the elderly with caution.

Acute renal failure following oral sodium phosphate bowel preparation: a nationwide case-crossover study.

BACKGROUND AND STUDY AIMS: Oral sodium phosphate (OSP) is a cleansing agent for colonoscopy. Recent reports have cited an increased risk of acute renal failure (ARF) in OSP bowel purgative users, but this risk remains under debate. This study was performed to evaluate the association between OSP and ARF in patients who underwent colonoscopy. PATIENTS AND METHODS: A population-based case-crossover study was conducted using the Korean Health Insurance Review and Assessment Service (HIRA) claims data from 1 January 2005 to 31 December 2009. The study population consisted of patients aged ≥ 50 years who underwent colonoscopies after an OSP prescription prior to their first hospitalization for ARF. For each patient, one hazard and four control periods were matched at specified time windows. Conditional logistic regression analysis was used to estimate the odds ratio (OR) and 95 % confidence interval (CI), adjusting for concomitant medications that could induce ARF. RESULTS: A total of 1105 patients were included (54 % male). The adjusted ORs for ARF related to the use of OSP when applying the 1-, 2-, 4-, 8-, or 12-week time windows were 3.7 (95 %CI 2.37 - 5.67), 3.5 (95 %CI 2.45 - 4.89), 3.0 (95 %CI 2.30 - 3.95), 2.4 (95 %CI 1.93 - 2.96), and 2.0 (95 %CI 1.69 - 2.46), respectively. When adopting an 8-week time window, the adjusted OR was 2.5 (95 %CI 1.98 - 3.16) for the subgroup without chronic renal failure. CONCLUSIONS: The use of OSP was significantly associated with ARF both in patients with and without co-morbidities.

Levothyroxine dose and fracture risk according to the osteoporosis status in elderly women.

OBJECTIVES: To evaluate the association between fracture risk and levothyroxine use in elderly women with hypothyroidism, according to previous osteoporosis history. METHODS: We conducted a cohort study from the Korean Health Insurance Review and Assessment Service claims database from January 2005 to June 2006. The study population comprised women aged ≥65 years who had been diagnosed with hypothyroidism and prescribed levothyroxine monotherapy. We excluded patients who met any of the following criteria: previous fracture history, hyperthyroidism, thyroid cancer, or pituitary disorder; low levothyroxine adherence; or a follow-up period <90 days. We categorized the daily levothyroxine doses into 4 groups: ≤50 µg/d, 51 to 100 µg/d, 101 to 150 µg/d, and >150 µg/d. The hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with the Cox proportional hazard model, and subgroup analyses were performed according to the osteoporosis history and osteoporosis-specific drug prescription status. RESULTS: Among 11 155 cohort participants, 35.6% had previous histories of osteoporosis. The adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.56 (95% CI, 1.03 to 2.37) in osteoporosis subgroup. In the highly probable osteoporosis subgroup, restricted to patients who were concurrently prescribed osteoporosis-specific drugs, the adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.93 (95% CI, 1.14 to 3.26). CONCLUSIONS: While further studies are needed, physicians should be concerned about potential levothyroxine overtreatment in elderly osteoporosis patients.

Prevention of venous thromboembolism, 2nd edition: Korean Society of Thrombosis and Hemostasis Evidence-based Clinical Practice Guidelines.

In 2010, we proposed the first Korean Guidelines for the Prevention of Venous Thromboembolism (VTE). It was applicable to Korean patients, by modifying the contents of the second edition of the Japanese guidelines for the prevention of VTE and the 8th edition of the American College of Chest Physicians (ACCP) evidence-based clinical practice guidelines. From 2007 to 2011, we conducted a nationwide study regarding the incidence of VTE after major surgery using the Health Insurance Review and Assessment Service (HIRA) database. In addition, we have considered the 9th edition of the ACCP Evidenced-Based Clinical Practice Guidelines, published in 2012. It emphasized the importance of clinically relevant events as opposed to asymptomatic outcomes with preferences for both thrombotic and bleeding outcomes. Thus, in the development of the new Korean guidelines, three major points were addressed: 1) the new guidelines stratify patients into 4 risk groups (very low, low, moderate, and high) according to the actual incidence of symptomatic VTE from the HIRA databases; 2) the recommended optimal VTE prophylaxis for each group was modified according to condition-specific thrombotic and bleeding risks; 3) guidelines are intended for general information only, are not medical advice, and do not replace professional medical care and/or physician advice.