Development of the Korean Standardized Antimicrobial Administration Ratio as a Tool for Benchmarking Antimicrobial Use in Each Hospital.

BACKGROUND: The Korea National Antimicrobial Use Analysis System (KONAS), a benchmarking system for antimicrobial use in hospitals, provides Korean Standardized Antimicrobial Administration Ratio (K-SAAR) for benchmarking. This article describes K-SAAR predictive models to enhance the understanding of K-SAAR, an important benchmarking strategy for antimicrobial usage in KONAS. METHODS: We obtained medical insurance claims data for all hospitalized patients aged ≥ 28 days in all secondary and tertiary care hospitals in South Korea (n = 347) from January 2019 to December 2019 from the Health Insurance Review & Assessment Service. Modeling was performed to derive a prediction value for antimicrobial use in each institution, which corresponded to the denominator value for calculating K-SAAR. The prediction values of antimicrobial use were modeled separately for each category, for all inpatients and adult patients (aged ≥ 15 years), using stepwise negative binomial regression. RESULTS: The final models for each antimicrobial category were adjusted for different significant risk factors. In the K-SAAR models of all aged patients as well as adult patients, most antimicrobial categories included the number of hospital beds and the number of operations as significant factors, while some antimicrobial categories included mean age for inpatients, hospital type, and the number of patients transferred from other hospitals as significant factors. CONCLUSION: We developed a model to predict antimicrobial use rates in Korean hospitals, and the model was used as the denominator of the K-SAAR.

Association between the change of total cholesterol during adolescence and depressive symptoms in early adulthood.

Increasing evidence suggests that serum lipids are associated with depressive symptoms. However, previous studies have mostly employed a cross-sectional design and assessed middle-aged or older adult populations, making it difficult to discern the impact of lipid changes early in life on the development of depression. Accordingly, we sought to investigate changes in blood cholesterol levels during adolescence and the development of depressive symptoms in early adulthood. This prospective cohort study included participants aged 15-16 years from the JS High School Study (JSHS), with an average follow-up of 6 years. Participants had no diagnosed depression at baseline. Multivariable linear regression models were used to estimate associations between changes in total cholesterol during adolescence and depressive symptoms in adulthood. Changes in total cholesterol during adolescence were classified as "consistently low," "decreased," "moderate," "increased," or "consistently high". In men, depressive symptoms were higher in the consistently low (ß = 3.20, p = 0.036) and increased total cholesterol groups (ß = 3.48, p = 0.017), compared with the moderate group. In the consistently high group, although a positive linear association was observed, it lacked statistical significance (ß = 2.71, p = 0.067). While similar tendencies were noted in women, the associations were not statistically significant. Consistently low or increased total cholesterol levels during adolescence may pose an increased risk of depressive symptoms in early adulthood. These findings suggest that different strategies should be adopted to manage the lipid risk factors with consideration of age and sex.

Cancer development in patients with COPD: a retrospective analysis of the National Health Insurance Service-National Sample Cohort in Korea.

BACKGROUND: COPD is a well-known risk factor for lung cancer, independent of smoking behavior. By investigating the retrospective National Health Insurance Service-National Sample Cohort (NHIS-NSC) in Korea, this study attempted to prove the hypothesis that COPD is a risk factor for major cancers developing outside of the lungs. We also aimed to investigate the environmental factors associated with the development of lung cancer in COPD patients. METHODS: This study analyzed data from the NHIS-NSC over a 12-year period. Among the 514,795 subjects in the NHIS-NSC, 16,757 patients who were diagnosed with any cancer from 2002 to 2003 were excluded. This cohort enrolled six arms consisting of never-smokers without COPD (N = 313,553), former smokers without COPD (N = 41,359), smokers without COPD (N = 112,627), never-smokers with COPD (N = 7789), former smokers with COPD (N = 1085), and smokers with COPD (N = 2677). RESULTS: Incident rate of lung cancer per 100,000 person-year was higher according to smoking and COPD (216 in non-COPD and 757 in COPD among never-smokers, 271 in non-COPD and 1266 in COPD among former smokers, 394 in non-COPD and 1560 in COPD among smokers, p <  0.01). Old age, male sex, lower BMI, low exercise level, history of diabetes mellitus, smoking, and COPD were independent factors associated with the development of lung cancer (p <  0.01). Multi-variable analyses showed that COPD, regardless of smoking status, contributed to the development of lung cancer, and colorectal cancer and liver cancer among other major cancers (p <  0.01). CONCLUSION: Our data suggested that COPD was an independent risk factor for the development of lung cancer, and colorectal cancer and liver cancer among other major cancers in the Korean population, regardless of smoking status.

Epidemiological Characterization of a Directed and Weighted Disease Network Using Data From a Cohort of One Million Patients: Network Analysis.

BACKGROUND: In the past 20 years, various methods have been introduced to construct disease networks. However, established disease networks have not been clinically useful to date because of differences among demographic factors, as well as the temporal order and intensity among disease-disease associations. OBJECTIVE: This study sought to investigate the overall patterns of the associations among diseases; network properties, such as clustering, degree, and strength; and the relationship between the structure of disease networks and demographic factors. METHODS: We used National Health Insurance Service-National Sample Cohort (NHIS-NSC) data from the Republic of Korea, which included the time series insurance information of 1 million out of 50 million Korean (approximately 2%) patients obtained between 2002 and 2013. After setting the observation and outcome periods, we selected only 520 common Korean Classification of Disease, sixth revision codes that were the most prevalent diagnoses, making up approximately 80% of the cases, for statistical validity. Using these data, we constructed a directional and weighted temporal network that considered both demographic factors and network properties. RESULTS: Our disease network contained 294 nodes and 3085 edges, a relative risk value of more than 4, and a false discovery rate-adjusted P value of <.001. Interestingly, our network presented four large clusters. Analysis of the network topology revealed a stronger correlation between in-strength and out-strength than between in-degree and out-degree. Further, the mean age of each disease population was related to the position along the regression line of the out/in-strength plot. Conversely, clustering analysis suggested that our network boasted four large clusters with different sex, age, and disease categories. CONCLUSIONS: We constructed a directional and weighted disease network visualizing demographic factors. Our proposed disease network model is expected to be a valuable tool for use by early clinical researchers seeking to explore the relationships among diseases in the future.

Development of Antibiotic Classification for Measuring Antibiotic Usage in Korean Hospitals Using a Modified Delphi Method.

In 2019, a project designed to develop a system for measuring and comparing antibiotic usage in hospitals was launched in Korea. As part of this project, we developed a means to classify antibiotic usage in Korean hospitals using a modified Delphi method. In results, the following categories of antibiotic classification were accepted for use in Korean hospitals: 1) broad-spectrum antibacterial agents predominantly used for hospital-onset infections in adults, 2) broad-spectrum antibacterial agents predominantly used for community-acquired infections in adults, 3) antibacterial agents predominantly used for resistant gram-positive infections in adults, 4) narrow-spectrum beta-lactam agents in adults, 5) antibacterial agents predominantly used for extensive antibiotic resistant gram-negative bacteria in adults, and 6) total antibacterial agents.

Free triiodothyronine/free thyroxine ratio rather than thyrotropin is more associated with metabolic parameters in healthy euthyroid adult subjects.

OBJECTIVE: The interrelation between TSH, thyroid hormones and metabolic parameters is complex and has not been confirmed. This study aimed to determine the association of TSH and thyroid hormones in euthyroid subjects and the relationship between thyroid function and metabolic risk factors. Furthermore, this study examined whether thyroid function has predictive power for metabolic syndrome. DESIGN: This is a cross-sectional study that included subjects in a medical health check-up programme at a single institution. PATIENTS: The study included 132 346 participants (66 991 men and 65 355 women) aged over 18 years who had TSH, free T4 (FT4) and free T3 (FT3) levels within the institutional reference ranges. MEASUREMENTS: Thyrotropin, FT4, FT3 and metabolic parameters including height, weight, waist circumference, blood pressure, serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, insulin and glucose were measured. RESULTS: There was a positive association between FT3/FT4 ratio and TSH in both men and women after adjusting for age, body mass index, smoking status and menopausal status (in women). The FT3/FT4 ratio and TSH were positively associated with risk of metabolic syndrome parameters including insulin resistance. The FT3/FT4 ratio had a greater predictive power than TSH for metabolic syndrome in both men and women. CONCLUSIONS: Thyrotropin levels were positively associated with FT3/FT4 ratio within the euthyroid range. The higher FT3/FT4 ratio is associated with increased risk of metabolic syndrome parameters and insulin resistance. FT3/FT4 ratio has a better predictive power for metabolic syndrome than TSH.

Association between Nitrogen Stable Isotope Ratios in Human Hair and Serum Levels of Leptin.

Stable isotope ratios have been reported to be potential biomarkers of dietary intake and nutritional status. High serum levels of leptin, a hormone which regulates energy metabolism and food intake, are associated with insulin resistance and metabolic syndrome. However, little is known about the association between stable isotope ratios and the metabolic risk in humans. We investigated whether the carbon and nitrogen stable isotope ratios in hair are associated with serum leptin levels. Hair samples were collected from 399 healthy adults (233 men and 166 women) aged 40 to 70 years of a community-based cohort in Korea and the bulk stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) were measured for all hair samples. Serum leptin levels were analyzed by radioimmunoassay. δ15N showed positive correlations with serum leptin levels. In multivariate models, increasing δ15N were associated with elevated serum leptin levels (defined as ≥ the median values), whereas δ13C were not significantly associated with serum leptin levels. The odds ratio (95% confidence interval) per 1‰ increase in δ15N for an elevated serum leptin level was 1.58 (1.11-2.26). In participants with high body mass index, δ15N showed positive associations with serum leptin levels, whereas these associations were not seen in participants with low body mass index. The nitrogen stable isotopic ratio in hair is positively associated with serum leptin levels. The hair δ15N could be used as a clinical marker to estimate metabolic risk.

Underweight and mortality.

OBJECTIVE: According to most prospective studies, being underweight (BMI<18·5 kg/m2) is associated with significantly higher mortality than being of normal weight, especially among smokers. We aimed to explore in a generally lean population whether being underweight is significantly associated with increased all-cause mortality. DESIGN: Prospective cohort study. SETTING: Korea Medical Insurance Corporation study with 14 years of follow-up. SUBJECTS: After excluding deaths within the first 5 years of follow-up (1993-1997) to minimize reverse causation and excluding participants without information about smoking and health status, 94 133 men and 48 496 women aged 35-59 years in 1990 were included. RESULTS: We documented 5411 (5·7 %) deaths in men and 762 (1·6 %) in women. Among never smokers, hazard ratios (HR) for underweight individuals were not significantly higher than those for normal-weight individuals (BMI=18·5-22·9 kg/m2): HR=0·87 (95 % CI 0·41, 1·84, P=0·72) for underweight men and HR=1·12 (95 % CI 0·76, 1·65, P=0·58) for underweight women. Among ex-smokers, HR=0·86 (95 % CI 0·38, 1·93, P=0·72) for underweight men and HR=3·77 (95 % CI 0·42, 32·29, P=0·24) for underweight women. Among current smokers, HR=1·60 (95 % CI 1·28, 2·01, P<0·001) for underweight men and HR=2·07 (95 % CI 0·43, 9·94, P=0·36) for underweight women. CONCLUSIONS: The present study does not support that being underweight per se is associated with increased all-cause mortality in Korean men and women.

A prospective study of serum adiponectin and regression of metabolic syndrome: The ARIRANG study.

Increased serum adiponectin levels may play a protective role in metabolic syndrome. However, few prospective studies have examined the effect of serum adiponectin in the improvement of metabolic components in subjects with metabolic syndrome. We investigated the association of serum adiponectin levels with the regression of metabolic syndrome in a population-based longitudinal study. A total of 1308 adults (575 men and 733 women) with metabolic syndrome at baseline were examined and followed. Baseline serum adiponectin concentrations were measured by radioimmunoassay. During an average of 2.6 years of follow-up, metabolic syndrome had disappeared in 184 men (29.8%) and 235 women (32.1%). In multivariable adjusted models, the odds ratio (95% confidence interval) for regression of metabolic syndrome comparing the highest to the lowest quartiles of adiponectin levels was 0.93 (0.56-1.53) in men and 2.48 (1.54-4.01) in women. Increased serum adiponectin is a predictor for the regression of metabolic syndrome in women. Adiponectin may have potential therapeutic applications in metabolic disease.

Addition of N-terminal pro-B-type natriuretic peptide levels to electrocardiography criteria for detection of left ventricular hypertrophy: the ARIRANG study.

The utility of electrocardiography (ECG) in screening for left ventricular hypertrophy (LVH) in general populations is limited mainly because its low sensitivity. B-type natriuretic peptide (BNP) is released due to the remodeling processes of LVH and could improve the diagnostic accuracy for the ECG criteria for LVH. We hypothesized that addition of BNP levels to ECG criteria could aid LVH detection compared with ECG alone in a general population. We enrolled consecutive 343 subjects from a community-based cohort. LVH was defined as LV mass index > 95 g/m(2) for females and > 115 g/m(2) for males according to echocardiography. The area under the receiver operator characteristic (ROC) curve to detect LVH was 0.55 (95% confidence interval [CI], 0.50-0.61) in Sokolow-Lyon criteria and 0.53 (0.47-0.59) in the Cornell voltage criteria. After addition of N-terminal-proBNP levels to the model, the corresponding areas under the ROC were 0.63 (0.58-0.69) and 0.64 (0.59-0.69), respectively. P values for the comparison in areas under the ROC for models with and without N-terminal-proBNP levels were < 0.001. These data suggest that addition of N-terminal-proBNP levels to ECG criteria could significantly improve the diagnostic accuracy of LVH in general populations.

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.

Trend in the Incidence of Severe Partial Edentulism among Adults Using the Korean National Health Insurance Service Claim Data, 2014-2018.

PURPOSE: Missing teeth is one of the most important indicators of oral health behavior and the result of dental caries, periodontal disease, and injuries. This study examined a trend in the incidence of severe partial edentulism (SPE) using the Korean National Health Insurance Service (KNHIS) data. MATERIALS AND METHODS: Data of adults aged ≥20 years were obtained from the KNHIS for the 2014-2018 period. SPE was defined in dental information within a population with a treatment history of dental scaling as having 1 to 8 natural teeth. Crude incidence rates (CIRs) and age-standardized incidence rates (AIRs) with 95% confidence interval were calculated per 100000 persons. The Cochran Armitage trend (CAT) test and average annual percentage change were used to analyze SPE trends. RESULTS: The CIRs among Korean adults were from 346.29 to 391.11 in 2014-2016 and from 391.11 to 354.09 in 2016-2018. The AIRs trend statistically increased by 4.31% from 346.29 to 376.80 and decreased by 4.72% from 376.80 to 342.10. The AIRs in men increased by 4.00% and decreased by 3.01%. The AIRs in women decreased by 2.18% and increased by 2.11% (CAT; p<0.01). The AIRs by region and income also showed trends of increase and decrease. CONCLUSION: The study showed that the incidence trend of SPE increased and decreased from 2014 to 2018. This result would be able to aid in the planning of public oral health, and may also serve as fundamental data for verifying the impact of the public oral health policies implemented.

A prospective study of epicardial adipose tissue and incident metabolic syndrome: the ARIRANG study.

Increased epicardial adipose tissue (EAT) may be closely associated with the development of metabolic abnormalities. We investigated whether EAT predicts the incident metabolic syndrome in a community-based, middle-aged population. The study subjects were comprised of 354 adults (134 men and 220 women) aged 40 to 70 yr without metabolic syndrome. Baseline EAT thickness, measured by echocardiography, was compared between subjects who developed new-onset metabolic syndrome at follow-up survey and those who did not. After an average of 2.2 yr of follow-up, 32 men (23.9%) and 37 women (16.8%) developed metabolic syndrome. Median EAT thickness at baseline was significantly higher in male subjects who developed metabolic syndrome than those who did not (1.52 mm vs 2.37 mm, P<0.001). The highest quartile of EAT thickness (≥2.55 mm) was associated with increased risk of progression to metabolic syndrome (Odds ratio [OR], 3.09; 95% confidence interval [CI], 1.11-8.66) after adjustment for age, smoking, alcohol intake, regular exercise, total energy intake, high sensitive C-reactive protein and homeostasis model assessment of insulin resistance in men. A significant association of EAT with incident metabolic syndrome was not seen in women (OR, 1.25; 95% CI, 0.54-2.90). In conclusion, increased EAT thickness is an independent predictor for incident metabolic syndrome in men.

The association between carbon and nitrogen stable isotope ratios of human hair and hypertension.

BACKGROUND: The relationship between stable isotope ratios and dietary protein sources has been reported. However, few studies have examined the effect of stable isotope ratios on metabolic risk in humans. We investigated whether the stable isotope ratios of carbon and nitrogen in human hair are associated with blood pressure and hypertension. METHODS: We conducted a cross-sectional study of 392 subjects (228 men and 164 women). Hair samples of the subjects were used for the measurement of stable isotope ratios of carbon (δ13C) and nitrogen (δ15N). RESULTS: The δ13C and δ15N values showed positive correlations with diastolic blood pressure in the subjects without antihypertensive medication. In the subjects without antihypertensive medication, the multivariable-adjusted odds ratio (95% confidence interval) for hypertension was 1.55 (1.04-2.30) per 1‰ increase in δ15N and 1.22 (0.86-1.73) per 1‰ increase in δ13C, respectively. However, in the subjects with antihypertensive medication, neither δ13C nor δ15N values showed a significant association with hypertension. CONCLUSIONS: The stable isotopic ratio of nitrogen in scalp hair is independently associated with hypertension in subjects without antihypertensive medication. The hair δ15N value might be used as a surrogate marker to screen a high-risk population for hypertension.

Clinical outcomes, when matched at presentation, do not vary between adult-onset Henöch-Schönlein purpura nephritis and IgA nephropathy.

Henöch-Schönlein purpura nephritis (HSPN) is considered a systemic form of immunoglobulin A nephropathy (IgAN). Although these are different pictures of a single disease, there are no studies directly comparing long-term outcomes of these two clinical entities. To clarify this, we studied 120 patients with biopsy-proven HSPN and 1070 patients with IgAN. The primary outcome was the composite of a doubling of baseline serum creatinine, end-stage renal disease, or death. Secondary outcomes included the individual renal outcomes or the rate of decline in estimated glomerular filtration rate. In the unmatched cohort, patients with HSPN had more vasculitic symptoms, more favorable histologic features, and were more commonly treated with steroids than patients with IgAN. The risk of reaching the primary outcome was significantly lower in HSPN patients than patients with IgAN (hazard ratio, 0.67). The 1:2 propensity score matching gave matched pairs of 89 patients with HSPN and 178 patients with IgAN, resulting in no differences in baseline conditions. In this matched cohort, there were no significant differences in reaching the primary and secondary outcomes between the two groups. Thus, after adjustment by propensity score matching, clinical outcomes did not differ between HSPN and IgAN, suggesting the two forms of the same disease have a similar prognosis.

Effects of icodextrin on patient survival and technique success in patients undergoing peritoneal dialysis.

BACKGROUND: Many studies have suggested clinical benefits of icodextrin in peritoneal dialysis (PD) patients regarding fluid management, glycaemic control and metabolic improvement. However, reports on whether icodextrin can improve patient and technique survival is sparse. METHODS: A total of 2163 patients from 54 centres in Korea who initiated PD from July 2003 to December 2006 were enrolled. Outcomes data were retrieved retrospectively from the Baxter Korea database. Among these patients, 641 patients who had been prescribed icodextrin for >50% of their PD duration were defined as the 'icodextrin' group and the remaining 1522 patients as the 'non-icodextrin' group. Propensity score matching yielded 640 matched pairs of patients. We compared all-cause mortality and technique failure rates between the two groups. RESULTS: There were no significant differences in age, gender, diabetes, cardiovascular comorbidity, socioeconomic status, biocompatible solution use in short dwells or centre experience between the two groups. Death occurred in 92 (14.4%) patients in the icodextrin group compared with 128 (20.0%) in the non-icodextrin group [hazard ratio (HR), 0.69; 95% confidence interval (CI), 0.53-0.90; P = 0.006]. In addition, icodextrin use was associated with a significantly lower risk of technique failure (HR, 0.60; 95% CI, 0.40-0.92; P = 0.018). The icodextrin group had fewer technique failures due to non-compliance compared with the non-icodextrin group whereas peritonitis- or ultrafiltration failure-related technique failure was not different between the two groups. CONCLUSION: This study further supports previous findings of long-term utilization of icodextrin solution improving patient and technique survival in PD patients. To confirm these results, a large randomized prospective study is warranted.

Topographical anatomy of the suprascapular nerve and vessels at the suprascapular notch.

Suprascapular nerve entrapment caused by the superior transverse scapular ligament (STSL) causes pain, and limitation of motion in the shoulder. To relieve these symptoms, suprascapular nerve decompression is performed through the resection of STSL. To describe and classify the topographic anatomy of the suprascapular notch, 103 cadaveric shoulders were dissected. The mean length and width of STSLs were 11.2 and 3.4 mm, respectively. The bony bridges replacing STSL in four shoulders were 8.2 mm long and 3.5 mm wide on average. The suprascapular nerve always ran through the notch under the STSL. All shoulders had a single suprascapular artery, while multiple suprascapular veins appeared in 21.3%. The arrangement of the suprascapular vessels was classified into three types: in Type I (59.4%), all suprascapular vessels ran over the STSL; in Type II (29.7%), the vessels ran over and under the STSL simultaneously; in Type III (10.9%), all vessels ran under the STSL. In 48.9% of cadavers, these types were bilaterally matched. The omohyoid muscle originated distantly from the STSL in 38.0%, was adjacent to it in 44.0%, and was partially over the STSL in 18.0%. The number of suprascapular vessels running under the STSL was positively correlated with the size of the STSL and the middle diameter of the suprascapular notch. Age was inversely correlated with the length of STSL. The STSL was wider in males than in females. This study provides details of the structural variations in the region of the suprascapular notch.

Incidence of edentulism among older adults using the Korean National Health Insurance Service database, 2013-2018.

OBJECTIVES: Population aging is rapidly accelerating worldwide. Oral diseases related to aging are also on the rise. This study examined trends in the incidence of edentulism among the older Korean population using data from the Korean National Health Insurance Service (KNHIS). METHODS: Data on older adults, aged ≥75 years of age, were obtained from the KNHIS for the period 2013-2018. Edentulism was defined as a treatment history of complete dentures in the KNHIS database. The exclusion criteria consisted of both disease codes and treatment codes related to conservative dental treatment, including periodontal and extraction treatment afterward. Crude incidence rates (CIRs) and age-standardized incidence rates (AIRs) with 95% confidence intervals were calculated and reported per 100,000 person-years by the direct method. Trends were tested by Cochrane Armitage models. RESULTS: Statistically significant increasing trends in both CIRs and AIRs were found among the older Korean population registered in the KNHIS (CIRs, 707.92 to 895.92; AIRs, 705.11 to 889.68; p<0.01). The incidence tended to increase in both genders (p<0.01). Both CIRs and AIRs in specific regions also showed slight but significant annual increases except for Jeju Island (p<0.01 or <0.05). The incidence showed increasing trends (p<0.01) in all income quintiles apart from the highest quintile. The edentulism incidence was highest in the lowest income group (the first quintile). CONCLUSIONS: Our data showed that the incidence of edentulism among the elderly showed an increasing trend from 2013 to 2018. This result provides a basis for future epidemiological studies on the incidence of edentulism in the older Korean population.

The cancer risk according to three subtypes of ANCA-associated vasculitis: A propensity score-matched analysis of a nationwide study.

OBJECTIVE: It remains unknown whether cancer risk differs among the three subtypes of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) and what the cancer risk factors are. We conducted a nationwide study in Korea to evaluate the risk of cancer in patients with AAV and to identify the risk factors for cancer. METHODS: We analyzed the Health Insurance Review and Assessment database of Korea and identified 1982 patients diagnosed with AAV between January 1, 2007 and December 31, 2017. The patients and controls with no history of AAV or cancer were matched 1:4 by propensity scores. The study outcome measure was incidence of cancer during 11 years of follow-up. RESULTS: Patients with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) numbered 684, 606, and 692, respectively. The overall incidence of cancer was higher among patients with AAV than in controls (HR 1.32, 95% CI 1.08-1.61). The risk of hematological malignancy, lung cancer, and bladder cancer in the GPA group, lung cancer in the MPA group, and hematological malignancy in the EGPA group were significantly higher than in controls (HR 7.39, 3.20, 4.20, 2.86, and 4.65, respectively). Age, male sex, GPA subtype, and cyclophosphamide use were significantly associated with cancer risk in patients with AAV. CONCLUSION: Overall cancer incidence was increased in patients with AAV. Cancer risk was higher in patients with GPA than in those with MPA or EGPA. The use of cyclophosphamide was associated with an increased risk of cancer, while rituximab was not.