Continuity of care between dyslipidemia patients and multiple providers: A cohort study.

OBJECTIVE: This study aimed to investigate the impacts of continuity of care (COC) between patients and multiple providers, i.e., doctors and community pharmacists, on clinical and economic outcomes. METHODS: This is a retrospective cohort study and analyzed Korean national claims data for ambulatory care setting between 2007 and 2018. Patients with dyslipidemia newly diagnosed in 2008 were identified. COC between providers and patients was computed using the continuity of care index (COCI). Based on COCIs, the study patients were allocated to four groups: HM/HP, HM/LP, LM/HP, and LM/LP. Each symbol represents H for high, L for low, M for doctor, and P for pharmacist. The primary study outcome was the incidence of atherosclerotic cardiovascular disease (ASCVD). RESULTS: 126,710 patients were included. Percentages of patients in the four study groups were as follows: HM/HP 35%, HM/LP 19%, LM/HP 12%, and LM/LP 34%. During the seven-year outcome period, 8,337 patients (6.6%) developed an ASCVD, and percentages in the study groups were as follows; HM/HP 6.2%, HM/LP 6.3%, LM/HP 6.8%, and LM/LP 7.1%. After adjusting for confounding covariates, only the LM/LP group had a significantly higher risk of ASCVD than the reference group, HM/HP (aHR = 1.16 [95% confidence interval = 1.10~1.22]). The risk of inappropriate medication adherence gradually increased 1.03-fold in the HM/LP group, 1.67-fold in the LM/HP, and 2.26-fold in the LM/LP group versus the HM/HP group after adjusting for covariates. Disease-related costs were lower in the HM/HP and LM/HP groups. CONCLUSIONS: The study shows that patients with high relational care continuity with doctors and pharmacists achieved better clinical results and utilized health care less, resulting in reduced expenses. Further exploration for the group that exhibits an ongoing relationship solely with pharmacists is warranted.

Identifying pregnancy episodes and estimating the last menstrual period using an administrative database in Korea: an application to patients with systemic lupus erythematosus.

OBJECTIVES: This study developed an algorithm for identifying pregnancy episodes and estimating the last menstrual period (LMP) in an administrative claims database and applied it to investigate the use of pregnancy-incompatible immunosuppressants among pregnant women with systemic lupus erythematosus (SLE). METHODS: An algorithm was developed and applied to a nationwide claims database in Korea. Pregnancy episodes were identified using a hierarchy of pregnancy outcomes and clinically plausible periods for subsequent episodes. The LMP was estimated using preterm delivery, sonography, and abortion procedure codes. Otherwise, outcome-specific estimates were applied, assigning a fixed gestational age to the corresponding pregnancy outcome. The algorithm was used to examine the prevalence of pregnancies and utilization of pregnancy-incompatible immunosuppressants (cyclophosphamide [CYC]/mycophenolate mofetil [MMF]/methotrexate [MTX]) and non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy in SLE patients. RESULTS: The pregnancy outcomes identified in SLE patients included live births (67%), stillbirths (2%), and abortions (31%). The LMP was mostly estimated with outcome-specific estimates for full-term births (92.3%) and using sonography procedure codes (54.7%) and preterm delivery diagnosis codes (37.9%) for preterm births. The use of CYC/MMF/MTX decreased from 7.6% during preconception to 0.2% at the end of pregnancy. CYC/MMF/MTX use was observed in 3.6% of women within 3 months preconception and 2.5% during 0-7 weeks of pregnancy. CONCLUSIONS: This study presents the first pregnancy algorithm using a Korean administrative claims database. Although further validation is necessary, this study provides a foundation for evaluating the safety of medications during pregnancy using secondary databases in Korea, especially for rare diseases.

Prevalence and outcomes of chronic comorbid conditions in patients with sepsis in Korea: a nationwide cohort study from 2011 to 2016.

BACKGROUND: Chronic comorbid conditions are common in patients with sepsis and may affect the outcomes. This study aimed to evaluate the prevalence and outcomes of common comorbidities in patients with sepsis. METHODS: We conducted a nationwide retrospective cohort study. Using data from the National Health Insurance Service of Korea. Adult patients (age ≥ 18 years) who were hospitalized in tertiary or general hospitals with a diagnosis of sepsis between 2011 and 2016 were analyzed. After screening of all International Classification of Diseases 10th revision codes for comorbidities, we identified hypertension, diabetes mellitus (DM), liver cirrhosis (LC), chronic kidney disease (CKD), and malignancy as prevalent comorbidities. RESULTS: Overall, 373,539 patients diagnosed with sepsis were hospitalized in Korea between 2011 and 2016. Among them, 46.7% had hypertension, 23.6% had DM, 7.4% had LC, 13.7% had CKD, and 30.7% had malignancy. In-hospital mortality rates for patients with hypertension, DM, LC, CKD, and malignancy were 25.5%, 25.2%, 34.5%, 28.0%, and 33.3%, respectively, showing a decreasing trend over time (P < 0.001). After adjusting for baseline characteristics, male sex, older age, use of mechanical ventilation, and continuous renal replacement therapy, LC, CKD, and malignancy were significantly associated with in-hospital mortality. CONCLUSIONS: Hypertension is the most prevalent comorbidity in patients with sepsis, and it is associated with an increased survival rate. Additionally, liver cirrhosis, chronic kidney disease, and malignancy result in higher mortality rates than hypertension and DM, and are significant risk factors for in-hospital mortality in patients with sepsis.

Increased cardiovascular risk in Korean patients with systemic lupus erythematosus: a population-based cohort study.

To determine the increased risk of major adverse cardiovascular events (MACE) in patients with systemic lupus erythematosus (SLE) compared to the general population in Korea. Using data from the National Health Insurance Service database spanning 2008 to 2018, incident SLE patients aged 18 years and above were selected along with a 1:4 age- and sex-matched control group. The crude incidence rate (IR) of MACE was calculated as the number of events per 1000 person-years and the IR ratio (IRR) for MACE was adjusted using generalized estimating equations. Subgroup analysis was conducted to evaluate the risk differences of overall MACE and its composites based on age and sex stratification. The study included 8568 SLE patients and 34,272 controls. The cumulative IR of MACE per 1000 person-years in SLE patients and controls were 4.08 and 1.30, respectively. After adjusting for confounders, SLE patients had a higher risk of MACE compared to the general population (adjusted IRR of 2.40 [95% confidence interval [CI] 1.88-3.05]), with no gender differences observed. The increased risk of MACE in SLE patients was highest in the 18-39 age group (IRR 11.70, 95% CI 5.95-23.01) and gradually decreased with age. The increased risk of ischemic stroke (IRR 2.41, 95% CI 1.84-3.15) and myocardial infarction (IRR 2.19, 95% CI 1.30-3.68) in SLE patients was comparable. The risk of MACE in SLE patients is 2.40 times higher than that of the general population, with a higher relative risk observed in younger individuals.

Cost-of-illness changes before and after the diagnosis of systemic lupus erythematosus: a nationwide, population-based observational study in Korea.

OBJECTIVES: To estimate the direct healthcare cost progression from before to after systemic lupus erythematosus (SLE) diagnosis and to compare healthcare costs by disease severity. METHODS: Patients with incident SLE diagnosed between 2008 and 2018 were identified from the Korean National Health Insurance database. Annual direct healthcare costs for 5 years before and after SLE were estimated and compared with those of age-, sex-, and calendar month-matched (1:4) controls, without SLE. Direct healthcare costs were compared by disease severity of SLE using regression analysis. RESULTS: Among 11 173 patients with SLE and 45 500 subjects without SLE, annual direct healthcare costs per person increased in the year before SLE diagnosis and peaked in the first year after diagnosis. They were 7.7-fold greater in the SLE patients than in the subjects without SLE ($5,871 vs $759). Severe SLE was associated with 3.284-fold (95% CI 3.075-3.507) higher annual costs than mild SLE during the year after diagnosis. Older age (age 60-79 years), lupus nephritis, interstitial lung diseases, and comorbidities such as avascular necrosis and chronic kidney disease were associated with higher annual direct healthcare costs (times [95% CI]) in the first year after diagnosis; aged 60-69, 1.119 [1.034-1.211], aged 70-79, 1.470 [1.342-1.611], 1.794 [1.711-1.881], 1.435 [1.258-1.638], 6.208 [4.541-8.487], and 1.858 [1.673-2.064], respectively. CONCLUSION: Patients with SLE incurred significantly high direct healthcare costs than subjects without SLE during the first year after diagnosis. Disease severity, older age, major organ involvements and comorbidities were associated with increased healthcare costs.

Risk of end-stage renal disease in patients with early-onset lupus nephritis: A population-based cohort study.

OBJECTIVE: To compare the risk of end-stage renal disease (ESRD) between patients with early-onset lupus nephritis (EOLN) and those with delayed-onset LN (DOLN). METHODS: This retrospective study of incident cases of systemic lupus erythematosus (SLE) used nationwide Korean claims databases and data from 2008 through 2018. We divided LN patients into two groups: the EOLN group (with LN onset within 12 months of SLE diagnoses) and the DOLN group (with LN onset later than 12 months after SLE diagnoses). Patients were observed from the date of LN diagnosis to the development of ESRD, death, or the last follow-up. Cox proportional hazards modeling was used to predict hazard ratios (HRs) for progression to ESRD with death as a competing risk. RESULTS: We identified 3779 incident SLE patients who developed LN during follow-up: 60 % (n = 2281) had EOLN, and 40 % (n = 1489) had DOLN. Sixty-nine patients with EOLN (3.0 %) and 29 patients with DOLN (1.9 %) progressed to ESRD. After adjusting for confounders, the ESRD risk associated with EOLN was comparable to the risk associated with DOLN (HR 1.10, 95 % confidence interval [CI] 0.57 to 2.11). In the subgroup of patients on aggressive immunosuppressive therapy (670 with EOLN and 179 with DOLN), the ESRD risk was higher in the DOLN group (HR 2.6, 95 % CI 1.11 to 6.10). CONCLUSION: The risk of ESRD was comparable between patients with EOLN and DOLN. However, among patients on aggressive immunosuppressive therapy, compared with EOLN, DOLN was associated with a higher risk of progression to ESRD.

The Association Between Institutional Case Volume of Hematopoietic Stem Cell Transplantation and Mortality.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is a complex, high-risk procedure with significant morbidity and mortality. The positive impact of higher institutional case volume on survival has been reported in various high-risk procedures. The association between annual institutional HSCT case volume and mortality was analyzed using the National Health Insurance Service database. METHODS: Data on 16,213 HSCTs performed in 46 Korean centers between 2007 and 2018 were extracted. Centers were divided into low- or high-volume centers using an average of 25 annual cases as the cut-off. Adjusted odds ratios (OR) for 1-year mortality after allogeneic and autologous HSCT were estimated using multivariable logistic regression. RESULTS: For allogeneic HSCT, low-volume centers (≤25 cases/y) were associated with higher 1-year mortality (adjusted OR 1.17, 95% CI 1.04-1.31, P = .008). However, low-volume centers did not show higher 1-year mortality (adjusted OR 1.03, 95% CI 0.89-1.19, P = .709) for autologous HSCT. Long-term mortality after HSCT was significantly worse in low-volume centers (adjusted hazard ratio [HR] 1.17, 95% CI, 1.09-1.25, P < .001 and adjusted HR 1.09, 95% CI, 1.01-1.17, P = .024, allogeneic and autologous HSCT, respectively) compared with high-volume centers. CONCLUSION: Our data suggest that higher institutional HSCT case volume seems to be associated with better short- and long-term survival.

Gcap14 is a microtubule plus-end-tracking protein coordinating microtubule-actin crosstalk during neurodevelopment.

Regulation of microtubule dynamics is required to properly control various steps of neurodevelopment. In this study, we identified granule cell antiserum-positive 14 (Gcap14) as a microtubule plus-end-tracking protein and as a regulator of microtubule dynamics during neurodevelopment. Gcap14 knockout mice exhibited impaired cortical lamination. Gcap14 deficiency resulted in defective neuronal migration. Moreover, nuclear distribution element nudE-like 1 (Ndel1), an interacting partner of Gcap14, effectively corrected the downregulation of microtubule dynamics and the defects in neuronal migration caused by Gcap14 deficiency. Finally, we found that the Gcap14-Ndel1 complex participates in the functional link between microtubule and actin filament, thereby regulating their crosstalks in the growth cones of cortical neurons. Taken together, we propose that the Gcap14-Ndel1 complex is fundamental for cytoskeletal remodeling during neurodevelopmental processes such as neuronal processes elongation and neuronal migration.

Risk prediction models incorporating institutional case volume for mortality after hip fracture surgery in the elderly.

INTRODUCTION: While higher institutional case volume is associated with better postoperative outcomes in various types of surgery, institutional case volume has been rarely included in risk prediction models for surgical patients. This study aimed to develop and validate the predictive models incorporating institutional case volume for predicting in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly. MATERIALS AND METHODS: Data for all patients (≥ 60 years) who underwent surgery for femur neck fracture, pertrochanteric fracture, or subtrochanteric fracture between January 2008 and December 2016 were extracted from the Korean National Health Insurance Service database. Patients were randomly assigned into the derivation cohort or the validation cohort in a 1:1 ratio. Risk prediction models for in-hospital mortality and 1-year mortality were developed in the derivation cohort using the logistic regression model. Covariates included age, sex, type of fracture, type of anaesthesia, transfusion, and comorbidities such as hypertension, diabetes, coronary artery disease, chronic kidney disease, cerebrovascular disease, and dementia. Two separate models, one with and the other without institutional case volume as a covariate, were constructed, evaluated, and compared using the likelihood ratio test. Based on the models, scoring systems for predicting in-hospital mortality and 1-year mortality were developed. RESULTS: Analysis of 196,842 patients showed 3.6% in-hospital mortality (7084/196,842) and 15.42% 1-year mortality (30,345/196,842). The model for predicting in-hospital mortality incorporating the institutional case volume demonstrated better discrimination (c-statistics 0.692) compared to the model without the institutional case volume (c-statistics 0.688; likelihood ratio test p value < 0.001). The performance of the model for predicting 1-year mortality was also better when incorporating institutional case volume (c-statistics 0.675 vs. 0.674; likelihood ratio test p value < 0.001). CONCLUSIONS: The new institutional case volume incorporated scoring system may help to predict in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly population.

Association between cost-sharing and drug prescribing in Korean elderly veterans with chronic diseases: A real-world claims data study.

This study aimed to investigate the relationship between cost-sharing and drug prescribing and its appropriateness in Korean elderly veterans with chronic conditions. This is a cross-sectional study using real-world claims data. Veterans with primary hypertension or dyslipidemia were compared with two controls with higher levels of cost-sharing. Study subjects (age ≥65 years) were selected through stratified random sampling and matching the individual attributes. The primary outcome was the annual amount of drugs prescribed per patient, and the secondary outcomes included several other measures investigating multifaceted aspects of drug prescribing, medical institution utilization behavior, and prescribing appropriateness. Gamma regression models or logistic regression models were employed. Veterans were prescribed 59%~74% more drugs (exp (ß) = 1.59 [95% confidence interval [CI] = 1.55-1.64] ~ 1.74 [1.70-1.79]) compared to the National Health Insurance (NHI) patients. This was attributed mainly to longer prescribing days (44%) and slightly more prescriptions (6%~7%) than NHI patients. Veterans spent 14%~15% higher medication costs. Veterans were less likely to visit multiple medical institutions by estimates of 0.77 (0.76-0.79) ~ 0.80 (0.79-0.82). Similar but smaller differences were observed between veterans and medical aid (MedAid) patients. The veteran patients showed a more than 50% increased risk of therapeutic duplication than the other two controls (adjusted odds ratio [ORs] = 1.47 [1.37-1.57] ~ 1.61 [1.50-1.72]). Inappropriate drug prescribing was also more common in veterans than the two controls (adjusted ORs = 1.20 [1.11-1.31] ~ 1.32 [1.22-1.43]). In Korean elderly veterans with chronic illnesses, a level of cost-sharing was associated with having more prescribed medicines, and increased inappropriate prescribing.

Different inhaled corticosteroid doses in triple therapy for chronic obstructive pulmonary disease: systematic review and Bayesian network meta-analysis.

A systematic review and Bayesian network meta-analysis is necessary to evaluate the efficacy and safety of triple therapy with different doses of inhaled corticosteroids (ICS) in stable chronic obstructive pulmonary disease (COPD). We selected 26 parallel randomized controlled trials (41,366 patients) comparing triple therapy with ICS/long-acting beta-agonist (LABA), LABA/long-acting muscarinic antagonist (LAMA), and LAMA in patients with stable COPD for ≥ 12 weeks from PubMed, EMBASE, the Cochrane Library, and clinical trial registries (search from inception to June 30, 2022). Triple therapy with high dose (HD)-ICS exhibited a lower risk of total exacerbation in pre-specified subgroups treated for ≥ 48 weeks than that with low dose (LD)-ICS (odds ratio [OR] = 0.66, 95% credible interval [CrI] = 0.52-0.94, low certainty of evidence) or medium dose (MD)-ICS (OR = 0.66, 95% CrI = 0.51-0.94, low certainty of evidence). Triple therapy with HD-ICS exhibited a lower risk of moderate-to-severe exacerbation in pre-specified subgroups with forced expiratory volume in 1 s < 65% (OR = 0.6, 95% CrI = 0.37-0.98, low certainty of evidence) or previous exacerbation history (OR = 0.6, 95% CrI = 0.36-0.999, very low certainty of evidence) than triple therapy with MD-ICS. Triple therapy with HD-ICS may reduce acute exacerbation in patients with COPD treated with other drug classes including triple therapy with LD- or MD-ICS or dual therapies.

Effect of Hospital Case-Volume on Mortality after Ovarian Cancer Surgery: A Population-Based Retrospective Cohort Study.

OBJECTIVES: The goal of ovarian cancer surgery has recently shifted from optimal cytoreduction to more complete resection. This study attempted to reassess and update the association between surgical case-volume and both in-hospital and long-term mortality after ovarian cancer surgery using recent data. DESIGN: This study is a population-based retrospective cohort study. Participants/Material: Data from all adult patients who underwent ovarian cancer surgery in Korea between 2005 and 2019 were obtained from the national database. A total of 24,620 patients underwent ovarian cancer surgery in 362 hospitals during the period. SETTING: In-hospital and 1-, 3-, 5-year mortality were set as primary and secondary outcomes. METHODS: Hospitals were categorized into high-volume (>90 cases/year), medium-volume (20-90 cases/year), and low-volume (<20 cases/year) centers considering overall distribution of case-volume. Postoperative in-hospital and long-term mortality were analyzed using logistic regression after adjusting for potential risk factors. RESULTS: Compared to high-volume centers (0.54%), in-hospital mortality was significantly higher in medium-volume (1.40%; adjusted odds ratio, 2.92; confidence interval, 1.82-3.73; p < 0.001) and low-volume (1.61%; adjusted odds ratio, 2.94; confidence interval, 2.07-4.17; p < 0.001) centers. In addition, 1-year mortality was 6.26%, 7.06%, and 7.94% for high-volume, medium-volume, and low-volume centers, respectively, and the differences among the groups were significant. However, case-volume effect was not apparent in 3- and 5-year mortality after ovarian cancer surgery. LIMITATIONS: Lacking clinical information such as staging or histologic diagnosis due to the nature of the administrative data should be considered in interpreting the data. CONCLUSIONS: Case-volume effect was observed for in-hospital and 1-year mortality after ovarian cancer surgery, while it was not clearly found in 3- or 5-year mortality. Dilution of the case-volume effect might be attributed to the high accessibility to care.

Institutional case volume and mortality after aortic and mitral valve replacement: a nationwide study in two Korean cohorts.

BACKGROUND: There are only a handful of published studies regarding the volume-outcome relationship in heart valve surgery. We evaluated the association between institutional case volume and mortality after aortic valve replacement (AVR) and mitral valve replacement (MVR). METHODS: Two separate cohorts of all adults who underwent AVR or MVR, respectively, between 2009 and 2016 were analyzed using a Korean healthcare insurance database. Hospitals performing AVRs were divided into three groups according to the average annual case volume: the low- (< 20 cases/year), medium- (20-70 cases/year), and high-volume centers (> 70 cases/year). Hospitals performing MVRs were also grouped as the low- (< 15 cases/year), medium- (15-40 cases/year), or high-volume centers (> 40 cases/year). In-hospital mortality after AVR or MVR were compared among the groups. RESULTS: In total, 7875 AVR and 5084 MVR cases were analyzed. In-hospital mortality after AVR was 8.3% (192/2318), 4.0% (84/2102), and 2.6% (90/3455) in the low-, medium-, and high-volume centers, respectively. The adjusted risk was higher in the low- (OR 2.31, 95% CI 1.73-3.09) and medium-volume centers (OR 1.53, 95% CI 1.09-2.15) compared to the high-volume centers. In-hospital mortality after MVR was 9.3% (155/1663), 6.3% (94/1501), and 2.9% (56/1920) in the low-, medium-, and high-volume centers, respectively. Compared to the high-volume centers, the medium- (OR 1.97, 95% CI 1.35-2.88) and low-volume centers (OR 2.29, 95% CI 1.60-3.27) showed higher adjusted risk of in-hospital mortality. CONCLUSIONS: Lower case volume is associated with increased in-hospital mortality after AVR and MVR. The results warrant a comprehensive discussion regarding regionalization/centralization of cardiac valve replacements to optimize patient outcomes.

Underestimation of Radiation Doses by Compliance of Wearing Dosimeters among Fluoroscopically-Guided Interventional Medical Workers in Korea.

This study aimed to estimate the level of underestimation of National Dose Registry (NDR) doses based on the workers' dosimeter wearing compliance. In 2021, a nationwide survey of Korean medical radiation workers was conducted. A total of 989 medical workers who performed fluoroscopically-guided interventional procedures participated, and their NDR was compared with the adjusted doses by multiplying the correction factors based on the individual level of dosimeter compliance from the questionnaire. Ordinal logistic regression analysis was performed to identify the factors for low dosimeter wearing. Based on the data from the NDR, the average annual effective radiation dose was 0.95 mSv, while the compliance-adjusted dose was 1.79 mSv, yielding an 89% increase. The risks for low compliance with wearing a badge were significantly higher among doctors, professionals other than radiologists or cardiologists, workers not frequently involved in performing fluoroscopically-guided interventional procedures, and workers who did not frequently wear protective devices. This study provided quantitative information demonstrating that the NDR data may have underestimated the actual occupational radiation exposure. The underestimation of NDR doses may lead to biased risk estimates in epidemiological studies for radiation workers, and considerable attention on dosimetry wearing compliance is required to interpret and utilize NDR data.

Hospital case-volume and mortality after lung cancer surgery: A population-based retrospective cohort study.

OBJECTIVES: Recent advances in lung cancer treatment warrants reassessment of the volume-outcome association in lung cancer surgery. This study reassessed the relationship between surgical case-volume and both in-hospital and long-term mortality after lung cancer surgery using a current database to reflect recent advances. MATERIALS AND METHODS: Using the database of the National Health Insurance Service in Korea, data of all adult patients who underwent lung cancer surgery in Korea between 2005 and 2019 were obtained. Hospitals were categorized by the annual number of lung cancer surgeries. Risk-adjusted in-hospital and 1, 3, 5-year mortality after surgery were assessed. RESULTS: A total of 84,194 lung cancer surgeries were performed in 163 centers during the study period. High-volume centers were defined as > 200 cases/year, medium-volume centers as 60-200 cases/year, and low-volume centers as < 60 cases/year. After adjustment, in-hospital mortality was significantly lower in high-volume centers (1.03%) compared to medium-volume centers (2.06%, adjusted odds ratio [OR], 1.43; 95% confidence interval [CI], 1.23-1.65; P < 0.001), and low-volume centers (3.08%, OR, 1.32; 95% CI, 1.16-1.51; P < 0.001). Long-term mortality was also significantly lower in high-volume centers compared to the other groups. CONCLUSION: High-volume centers showed lower in-hospital and long-term mortality compared to centers with less case-volume.

COX-2 Inhibitor Use as an Early Treatment Option for Knee Osteoarthritis Patients in Korea: A Population-Based Cross-Sectional Study.

BACKGROUND: To investigate the use of cyclooxygenase-2 (COX-2) inhibitors as an initial drug treatment for knee osteoarthritis (OA) patients. METHODS: From 2013 to 2015, patients with knee OA were identified from the Korean nationwide claims database. Among them, we extracted incident cases of knee OA to identify the initial drug treatment. Trends in the use of non-steroid anti-inflammatory drugs (NSAIDs) including COX-2 inhibitors were analyzed during the first year after their diagnosis. Associated factors for COX-2 inhibitor use were examined using a multivariate logistic regression model. RESULTS: We identified 2,857,999 incident knee OA patients (955,259 in 2013, 981,314 in 2014, and 921,426 in 2015). The mean ± standard deviation age of patients was 64.2 ± 9.8 years. The frequency of COX-2 inhibitor use as initial treatment increased from 3.5% in 2013 to 7.2% in 2015 (P < 0.01). In patients taking the medication regularly for one year after diagnosis (medication possession ratio ≥ 50%), COX-2 inhibitor use also rapidly increased from 5.5% in 2013 to 11.1% in 2015 (P < 0.01). However, the frequencies of non-selective NSAID and analgesic use did not decrease remarkably. Factors associated with patients using COX-2 inhibitors on initial drug treatment were older age (odds ratio [OR], 1.08), female (OR, 1.24), and comorbidity (OR, 1.03). Type of institution, physician speciality, and insurance type of patients were also associated. CONCLUSION: In Korea, COX-2 inhibitors have rapidly increased as an initial treatment for knee OA patients, but it has not appeared to reduce the use of non-selective NSAIDs and analgesics.

Relationship between continuity of care and clinical outcomes in patients with dyslipidemia in Korea: a real world claims database study.

Dyslipidemia is a risk factor for atherosclerotic cardiovascular disease and requires proactive management. This study aimed to investigate the association between care continuity and the outcomes of patients with dyslipidemia. We conducted a retrospective cohort study on patients with dyslipidemia by employing the Korea National Health Insurance claims database during the period 2007-2018. The Continuity of Care Index (COCI) was used to measure continuity of care. We considered incidence of atherosclerotic cardiovascular disease as a primary outcome. A Cox's proportional hazards regression model was used to quantify risks of primary outcome. There were 236,486 patients newly diagnosed with dyslipidemia in 2008 who were categorized into the high and low COC groups depending on their COCI. The adjusted hazard ratio for the primary outcome was 1.09 times higher (95% confidence interval: 1.06-1.12) in the low COC group than in the high COC group. The study shows that improved continuity of care for newly-diagnosed dyslipidemic patients might reduce the risk of atherosclerotic cardiovascular disease.

Healthcare Resource Utilization After Living Liver Donation: A Retrospective Case-Control Study.

BACKGROUND: Living liver donation is generally considered safe, but donors may experience short- or long-term complications. The purpose of this study was to assess healthcare resource utilization after liver donation in living liver donors in comparison with the general population. METHODS: Outpatient or emergency department visits and hospital admissions were compared between living liver donors who underwent hepatic resection for living liver donation between 2004 and 2018 and the matched general population. Healthcare resource utilization data for 5 y after liver donation were collected from the National Health Insurance Service database. For every living liver donor, 4 individually matched nondonors were selected from the National Health Insurance Service database using age, sex, preexisting comorbidities, and previous healthcare utilization history. RESULTS: A total of 1886 living liver donors and 7309 nondonors were included. In the first year after donation, living liver donors required more outpatient department visits (7 [4-13] versus 3 [1-7], P < 0.001) and more emergency department visits (13.33% versus 0.15%, P < 0.001) compared with matched nondonors. A similar trend persisted for 5 y after donation. The number of hospital admissions of living liver donors was higher for up to 2 y after donation with longer hospital length of stay (13.0 [10.5-16.0] d versus 5.0 [3.0-9.0] d, P < 0.0001). CONCLUSIONS: Healthcare resource utilization in living liver donors for 5 y after donation was higher compared with matched nondonors. The higher healthcare resource demand may be related to postoperative complications or lowered threshold for healthcare resource utilization after donation.

Institutional case volume-incorporated mortality risk prediction model for cardiac surgery.

BACKGROUND: Most risk prediction models predicting short-term mortality after cardiac surgery incorporate patient characteristics, laboratory data, and type of surgery, but do not account for surgical experience. Considering the impact of case volume on patient outcome after high-risk procedures, we attempted to develop a risk prediction model for mortality after cardiac surgery that incorporates institutional case volume. METHODS: Adult patients who underwent cardiac surgery from 2009 to 2016 were identified. Patients who underwent cardiac surgery (n = 57,804) were randomly divided into the derivation cohort (n = 28,902) or the validation cohorts (n = 28,902). A risk prediction model for in-hospital mortality and 1-year mortality was developed from the derivation cohort and the performance of the model was evaluated in the validation cohort. RESULTS: The model demonstrated fair discrimination (c-statistics, 0.76 for in-hospital mortality in both cohorts; 0.74 for 1-year mortality in both cohorts) and acceptable calibration. Hospitals were classified based on case volume into 50 or less, 50-100, 100-200, or more than 200 average cardiac surgery cases per year and case volume was a significant variable in the prediction model. CONCLUSIONS: A new risk prediction model that incorporates institutional case volume and accurately predicts in-hospital and 1-year mortality after cardiac surgery was developed and validated.

Comparative Effectiveness of Azathioprine Versus Cyclosporine as an Initial Treatment for Idiopathic Inflammatory Myopathies: A Population-Based Observational Study.

OBJECTIVE: To compare the effectiveness of azathioprine (AZA) and cyclosporine (CsA) as initial treatments for patients with idiopathic inflammatory myopathies (IIM). METHODS: A retrospective cohort study was conducted using information from the National Health Insurance Service database of Republic of Korea. Patients with IIM who had started AZA or CsA as initial treatment between January 2007 and December 2011 were selected for the study. They were followed from the day of treatment initiation to the occurrence of study outcomes or the end of the study until December 2016. Effectiveness outcomes, defined as switching the drug or adding immunosuppressants, and discontinuation of corticosteroids, were compared between the two groups. The Cox proportional-hazards model was used to calculate the adjusted relative risk (aRR) with 95% confidence interval (CI) between the AZA and CsA groups. RESULTS: A total of 376 patients with incident IIM who used AZA (n = 288) or CsA (n = 88) were identified. The aRR of switching the drug or adding immunosuppressants (1.45 [95% CI 0.99-2.11]) was not significantly different between the CsA and AZA groups. Among patients who were treated with corticosteroids at baseline, the rate of discontinuation of corticosteroids was not different between the two groups (1.69 [95% CI 0.82-3.47]). CONCLUSIONS: The effectiveness of AZA and CsA as initial treatments for the management of IIM was comparable.