Incidence of atrial fibrillation in patients with renal infarction: A retrospective cohort analysis of the Korean national health insurance registry.

BACKGROUND: Regarding the pathophysiology of renal infarction (RI), cardioembolic causes could have large proportion. However, there are notable variations in prevalence of atrial fibrillation (AF) among patients with RI across different studies, ranging from 17 to 65%. The primary objective of this study is to analyze the incidence of AF in patients with RI. METHODS: This nationwide retrospective cohort study enrolled 5200 patients with RI from the Korean National Institute of Health Services database spanning the years 2013 to 2019. The study accessed the AF incidence rate within 12 months in patients without a prior history of AF. Events occurring within 3 months of RI diagnosis were excluded to mitigate cases diagnosed during the initial screening or those with AF diagnoses that were potentially overlooked in the past. RESULTS: AF occurred in 19.1% of patients with RI over the entire period (median: 2.5 years, interquartile range 1.04-4.25 years). The majority of AF cases (16.1%) occured within the first year, resulting in an overall incidence rate of 7.0 per 100 person-years. Patients with newly developed AF were, on average, older than those who did not develop AF (64.1 vs. 57.3 years, P < 0.001). The independent predictors of AF were identified as age, male sex, higher body mass index, current smoking, ischemic heart disease, and heart failure. CONCLUSIONS: Physicians should consider the implementation of active rhythm monitoring for patients with RI to identify potential occurrence of subclinical AF, even if not initially diagnosed during the initial screening after RI diagnosis.

Prognosis of amyotrophic lateral sclerosis patients after tracheostomy invasive ventilation in Korea.

Background: Tracheostomy invasive ventilation (TIV) is applied to a subset of amyotrophic lateral sclerosis (ALS) patients; however, its frequency and impact on prognosis vary across countries. Methods: We conducted a nationwide retrospective cohort study using Korean National Health Insurance claims data. All patients diagnosed with sporadic ALS from 2012 to 2017 were included, with the observation period until 2020. The survival time between the TIV and non-TIV groups was compared using propensity score matching analysis, and prognostic factors were assessed within the TIV group. Results: This study included 3484 ALS patients (mean [standard deviation] age, 62.4 [11.9] years, 60.4% male), among whom 1230 (35.3%) underwent TIV. After 1:1 propensity score matching, the survival duration between the two groups was not significantly different (28 vs. 25 months, p = 0.057). Cox regression indicated that older age (hazard ratios [HRs] for each decade compared to <40 years: 3.89, 3.83, 5.30, 6.78, and 8.40 [≥80 years]; p < 0.005 for all) and lower income (HR, 1.28; 95% confidence interval [CI], 1.09-1.52; p = 0.003) negatively impacted survival, while gastrostomy (HR, 0.57; 95% CI, 0.50-0.66; p < 0.001) and supportive care services (HR, 0.43; 95% CI, 0.32-0.59; p < 0.001) were associated with prolonged survival. Conclusions: TIV was administered to more than one-third of Korean ALS patients without significant survival prolongation. Older age, lower income, lack of gastrostomy, and insufficient supportive care were independent poor prognostic factors for survival, underscoring the importance of comprehensive management for ALS patients.

Temporal Trend of the Incidence and Characteristics of Renal Infarction: Korean Nationwide Population Study.

BACKGROUND: Large-scale studies about epidemiologic characteristics of renal infarction (RI) are few. In this study, we aimed to analyze the incidence and prevalence of RI with comorbidities in the South Korean population. METHODS: We investigated the medical history of the entire South Korean adult population between 2013 and 2019 using the National Health Insurance Service database (n = 51,849,591 in 2019). Diagnosis of RI comorbidities were confirmed with International Classification of Disease, Tenth Revision, Clinical Modification codes. Epidemiologic characteristics, distribution of comorbidities according to etiologic mechanisms, and trend of antithrombotic agents were estimated. RESULTS: During the 7-years, 10,496 patients were newly diagnosed with RI. The incidence rate increased from 2.68 to 3.06 per 100,000 person-years during the study period. The incidence rate of RI increased with age peaking in the 70s with 1.41 times male predominance. The most common comorbidity was hypertension, followed by dyslipidemia and diabetes mellitus. Regarding etiologic risk factor distribution, high embolic risk group, renovascular disease group, and hypercoagulable state group accounted for 16.6%, 29.1%, and 13.7% on average, respectively. For the antithrombotic treatment of RI, the prescription of antiplatelet agent gradually decreased from 17.0% to 13.0% while that of anticoagulation agent was maintained around 35%. The proportion of non-vitamin K antagonist oral anticoagulants remarkably increased from only 1.4% to 17.6%. CONCLUSION: Considering the progressively increasing incidence of RI and high prevalence of coexisting risk factors, constant efforts to raise awareness of the disease are necessary. The current epidemiologic investigation of RI would be the stepping-stone to establishing future studies about clinical outcomes and optimal treatment strategies.

Increased incidence of dementia following herpesvirus infection in the Korean population.

Herpesviruses affect the development of dementia. We investigated the association between herpes infection and subsequent diagnoses of dementia. Data from the National Health Insurance Service of South Korea were used. Patients aged ≥50 years with the relevant diagnostic codes in the reference year 2009 were included and prospectively reviewed from January 2010 to December 2018. All study participants were followed from the index date until the onset of dementia, death, or the study endpoint. The three cohorts comprised 92,095 patients with herpes simplex virus (HSV) infections, 97,323 patients with varicella-zoster virus (VZV) infections, and 183,779 controls. During the follow-up period, 15,831 (17.19%) subjects with HSV infection and 17,082 (17.55%) VZV-infected subjects, compared to 27,028 (14.17%) control subjects, were subsequently diagnosed with dementia (all, P < .001). The adjusted hazard ratio for developing dementia was found to be 1.18 (95% confidence interval [CI]; 1.16-1.20) in HSV and 1.09 (95% CI; 1.07-1.11) in VZV patients (all, P < .001). HSV1 infections such as oral or ocular subtypes, but not HSV2, anogenital subtype, were associated with dementia, including several subtypes such as Alzheimer's disease (AD), vascular dementia, and dementia with Lewy bodies. VZV infection is also associated with AD. In this Korean nationwide population-based cohort study, both HSV and VZV infections were associated with a higher risk of dementia, particularly AD. Among the subtypes of HSV infection, HSV1 is associated with a risk of dementia. Further studies including appropriate public health interventions could evaluate the causality of these relationships.

Analysis of treatment outcomes according to the cycles of adjuvant chemotherapy in gastric cancer: a retrospective nationwide cohort study.

BACKGROUND: One-year S-1 or six-month capecitabine/oxaliplatin (CAPOX) has been the standard adjuvant chemotherapy for gastric cancer (GC). We investigated outcomes according to the cycles of adjuvant chemotherapy, using data from the Korean Health Insurance and Assessment Service. METHODS: A total of 20,552 patients, including 13,614 patients who received S-1 and 6,938 patients who received CAPOX extracted from 558,442 patients were retrospectively analyzed. The five-year overall survival rate was evaluated according to the duration of adjuvant chemotherapy. RESULTS: The five-year overall survival rate gradually increased according to the increase in adjuvant chemotherapy cycles in both the S-1 (≤ 5 cycles: 48.4%, hazard ratio [HR] 4.06, 95% confidence interval [CI] 3.74-4.40, P < 0.0001; 5 < cycles ≤ 6: 55.4%, HR 3.08, 95% CI 2.65-3.57, P < 0.0001; 6 < cycles ≤ 7: 64.1%, HR 2.11, 95% CI 1.84-2.41, P < 0.0001; 7 < cycles < 8: 71.1%, HR 1.60, 95% CI 1.39-1.84, P < 0.0001; ≥ 8 cycles: 77.9%) and the CAPOX groups (≤ 4 cycles: 43.5%, HR 3.20, 95% CI 2.84-3.61, P < 0.0001; 5 cycles: 45.3%, HR 2.63, 95% CI 2.11-3.27, P < 0.0001; 6 cycles: 47.1%, HR 2.09, 95% CI 1.76-2.49, P < 0.0001; 7 cycles: 55.3%, HR 1.63, 95% CI 1.35-1.96, P < 0.0001; ≥ 8 cycles: 67.2%). CONCLUSIONS: Reducing the treatment cycles of adjuvant chemotherapy in GC with S-1 or CAPOX showed inferior survival outcomes. Completing the standard duration of adjuvant chemotherapy with S-1 or CAPOX would be strongly recommended.

Influence of concomitant percutaneous transluminal angioplasty with percutaneous coronary intervention on clinical outcomes of stable lower extremity artery diseases.

Concomitant percutaneous transluminal angioplasty (PTA) at the time of percutaneous coronary intervention (PCI) is often performed because lower extremity artery disease (LEAD) commonly coincides with coronary artery disease. We investigated the impact of concomitant PTA on both cardiovascular and limb outcomes in the Korean National Health Insurance Service registry. Among 78,185 patients undergoing PCI, 6563 patients with stable LEAD without limb ischemia were included. After 1:5 propensity score matching was conducted, 279 patients in the PTA + PCI group and 1385 patients in the PCI group were compared. Multivariate Cox proportional hazard models showed that the risk of all-cause death was higher in the PTA + PCI group than in the PCI group, whereas the risks of myocardial infarction, repeat revascularization, stroke, cardiovascular death and bleeding events were not different between the 2 groups. In contrast, the risks of end-stage renal disease and unfavorable limb outcomes were higher in the PTA + PCI group. Mediation analyses revealed that amputation and PTA after discharge significantly mediated the association between concomitant PTA and all-cause death. Concomitant PTA was not associated with an increased risk of cardiovascular events but may increase the risk of all-cause death mediated by unfavorable renal and limb outcomes in patients with stable LEAD.

Increased risks of aortic regurgitation and atrial fibrillation in radiographic axial spondyloarthritis patients: a 10-year nationwide cohort study.

Background: To compare the incidences of aortic regurgitation, atrial fibrillation (AF), and atrioventricular (AV) block II-III between radiographic axial spondyloarthritis (r-axSpA) patients and the general population (GP). Methods: National Health Insurance Services data were used. R-axSpA patients (N = 8877) and the age- and sex-matched GP (N = 26,631) were followed from August 2006 to December 2019. Incidence rates and standardized incidence ratios (SIRs) of aortic regurgitation, AF, and AV block II-III were compared between these groups. Ten-year incidence rates and hazard ratios (HRs) were calculated by the Kaplan-Meier method and Cox regression analysis. Results: Incidence rates of aortic regurgitation, AV block II-III, and AF in the r-axSpA group were 0.42, 0.21, and 4.0 per 1000 person-years (PYs), respectively. In the r-axSpA group, the SIR for aortic regurgitation was highest among 40- to 49-year-old men (4.11). Incidence rates of aortic regurgitation and AF were higher in the r-axSpA group than in the GP group (0.42 versus 0.18 per 1000 PYs 4.00 versus 3.13 per 1000 PYs, both p < 0.001, respectively), whereas the difference was insignificant for AV block II-III (0.21 versus 0.14 per 1000 PYs, p = 0.222). In multivariate analysis, r-axSpA was associated with a higher hazard (risk) for the development of aortic regurgitation and AF [HR (95% confidence interval) = 2.55 (1.49-4.37) and 1.20 (1.04-1.39), respectively], but the difference was insignificant for AV block II-III [HR (95% confidence interval) = 1.17 (0.59-2.31)]. Conclusions: Compared with the GP, r-axSpA patients are at increased risk of aortic regurgitation and AF, but not AV block II-III. These patients should be carefully monitored for occurrence of aortic regurgitation and AF.

Anaerobe coverage is important for the prognosis of pyogenic liver abscess: A population-based study in Korea.

BACKGROUND: Gram-negative bacteria such as Klebsiella pneumoniae and Escherichia coli are the most common cause of pyogenic liver abscess (PLA). We investigated whether the use of anaerobic-covering antibiotics is essential for the treatment of pyogenic liver abscess. METHODS: We analyzed the Health Insurance Review and Assessment Service data in Korea between 2007 and 2017. We classified PLA into two groups: a group using antibiotics that inhibited only aerobic strains (anaerobe (-) group) and a group using antibiotics that inhibited both aerobic and anaerobic strains (anaerobe (+) group). The primary outcome was the difference in in-hospital mortality between the two groups. RESULTS: During this period, a total of 30,690 PLA patients were obtained. There were 6733 patients in the anaerobe (-) group and 23,957 patients in the anaerobe (+) group. In-hospital mortality was significantly lower in the anaerobe (+) group than the anaerobe (-) group (7.9% vs. 15.6%, p < 0.001). In multivariate analysis, the use of anaerobic antibiotics reduced the in-hospital mortality by 42% (odds ratio 0.42, 95% confidence interval 0.38-0.46, p < 0.001) after adjusting for age and comorbidities. Furthermore, the improvement of in-hospital mortality was present regardless of the presence of cancer or diabetes. CONCLUSION: The use of broad-spectrum empirical antibiotics covering anaerobic strains is important for the treatment of pyogenic liver abscess.

Long-term prognosis and causes of death among survivors after out-of-hospital cardiac arrest: A population-based longitudinal study.

BACKGROUND: We aimed to identify the long-term prognosis and causes of death of out-of-hospital cardiac arrest (OHCA) survivors. METHODS: Using claims data from the National Health Insurance Service (NHIS) database, we included 4937 OHCA patients (aged ≥ 18 years) who were hospitalized between January 2005 and December 2015 and had survived for 30 days or more. The endpoints were long-term mortality and causes of death. Subgroup analyses were performed based on whether cardiac procedures were performed, and risk factors associated with cardiac and noncardiac deaths were identified. RESULTS: We followed 4937 OHCA patients for a median of 3.3 years and up to 14 years of follow-up. The all-cause 1-, 3-, 5-, and 10-year cumulative mortality were 35.2%, 46.5%, 52.3%, and 62.7%, respectively. Regarding the 1130 OHCA survivors who had undergone cardiac procedures, the all-cause 1-, 3-, 5-, and 10-year cumulative mortality were 10.7%, 16.9%, 21.4%, and 30.6%, respectively. More patients (56.2%) died from noncardiovascular causes than from cardiovascular causes (43.8%) among the 2738 total patients who had died. The proportion of patients with cardiac death was significantly higher in the patient group with a cardiac procedure than in the group without a cardiac procedure (49.6% vs. 31.7%; P value < 0.001). A higher Charlson comorbidity index (CCI) was associated with an increased risk of cardiac mortality in the cardiac procedure group. CONCLUSIONS: The long-term mortality among OHCA survivors remains high, particularly within the first year. Individual characteristics are crucial for the follow-up of OHCA survivors and may help improve their long-term prognosis.

Validation of Cancer Diagnosis Based on the National Health Insurance Service Database versus the National Cancer Registry Database in Korea.

PURPOSE: This study aimed to assess the feasibility of operational definitions of cancer patients in conducting cancer-related studies using the claims data from the National Health Insurance Service (NHIS). MATERIALS AND METHODS: Cancer incidence data were obtained from the Korean Central Cancer Registry, the NHIS primary diagnosis, and from the rare and intractable disease (RID) registration program. RESULTS: The operational definition with higher sensitivity for cancer patient verification was different by cancer type. Using primary diagnosis, the lowest sensitivity was found in colorectal cancer (91.5%; 95% confidence interval [CI], 91.7 to 92.0) and the highest sensitivity was found in breast cancer (97.9%; 95% CI, 97.8 to 98.0). With RID, sensitivity was the lowest in liver cancer (91.9%; 95% CI, 91.7 to 92.0) and highest in breast cancer (98.1%; 95% CI, 98.0 to 98.2). In terms of the difference in the date of diagnosis in the cancer registration data, > 80% of the patients showed a < 31-day difference from the RID definition. CONCLUSION: Based on the NHIS data, the operational definition of cancer incidence is more accurate when using the RID registration program claims compared to using the primary diagnosis despite the relatively lower concordance by cancer type requires additional definitions such as treatment.

Seeking adaptation from uncertainty: Coping strategies of South Korean women with endometriosis.

Women with endometriosis may experience uncertainty owing to the characteristics of the disease, including vague symptom patterns, delayed diagnosis, and long-term management with no cure. However, women use various coping strategies to adapt to the uncertainty caused by their endometriosis. This descriptive qualitative study explored the coping experiences of women with endometriosis to reduce their uncertainty about the disease and to achieve successful adaptation to their lives with endometriosis. By using convenience and purposive sampling methods, qualitative data were collected from 14 women in South Korea (mean age = 37.7 years, age range = 27-54 years), who were diagnosed with endometriosis through laparoscopy or open surgery. All interview data were thematically analyzed. Four themes were identified as adaptive coping experiences: (1) gaining self-control over the ambiguous disease; (2) regaining the daily routines destroyed by the disease; (3) being emotionally supported and expressing oneself when feeling unsupported by society; and (4) taking an active role in one's treatment plan by being self-directed. Patients' sense of self-control and self-directedness regarding the disease and the treatment process were important to adapt to life with endometriosis. In addition, regaining stable daily routines as well as being emotionally supported were critical for decreasing their uncertainty. This paper has widespread implications, including the need for training or a continuing education program for health professionals to enhance their competencies when caring for women with endometriosis and the need for social efforts to increase awareness of the disease.

A population-based study of pyogenic liver abscess in Korea: Incidence, mortality and temporal trends during 2007-2017.

BACKGROUND/AIMS: Although the epidemiology of pyogenic liver abscess (PLA) continues to change, only a few population-based studies have been conducted in Korea. This study investigated the epidemiology and clinical outcomes of PLA patients during a period of 10 years. METHODS: We analysed the Health Insurance Review and Assessment Service data between 2007 and 2017. The data included annual incidence rates, demographic data, underlying diseases, complications and mortality of PLA patients. RESULTS: The annual incidence of PLA for all age groups was 10.9 per 100 000 population. The incidence was gradually increased from 5.7 per 100 000 in 2007 to 14.4 per 100 000 in 2017. In patients with liver abscess, the prevalence of diabetes and malignancy were 37.24% and 26.5% respectively. Metastatic infection was reported in 1.74% of the patients, and endophthalmitis was most common. The mean in-hospital mortality was 9.6%, and there was no significant difference in mortality by year during the observation period. Mortality increased with age and was greatly affected by the underlying diseases, especially cancer. Based on the multivariate analysis results, the mortality of PLA patients was associated with older age, female sex, diabetes, malignancy and chronic kidney disease. CONCLUSION: The PLA incidence is rapidly increasing in Korea, especially in people with comorbidities. In addition, the causes and risk factors of PLA infections are changing and thus further research on epidemiology, different diagnosis and management approaches is required.

Brachytherapy utilization rate and effect on survival in cervical cancer patients in Korea.

OBJECTIVE: External beam radiation therapy (EBRT) with concurrent chemotherapy followed by intracavitary brachytherapy is the standard treatment in locally advanced cervical cancer. This study examined the brachytherapy utilization rate and evaluated the effect of brachytherapy on survival in cervical cancer patients in Korea. METHODS: In this study, data from the Korea Central Cancer Registry and Korean National Health Insurance Service and data on mortality from Statistics Korea were linked and used. Patients with other cancers, distant metastasis at diagnosis, or unknown stage or who underwent hysterectomy were excluded. A total of 12,721 cervical cancer patients were analyzed in this study. RESULTS: The brachytherapy utilization rate (%) was calculated as the proportion of patients who received brachytherapy among those who received curative EBRT. The brachytherapy utilization rate decreased from 84% in 2005 to 78% in 2013 (p<0.001). Brachytherapy utilization rates varied by region, ranging from 72% to 100% except for in Jeju Island, where the rate was 56%. The brachytherapy utilization rate was lower in patients older than 80 years; patients with localized disease, non-squamous cell carcinoma, or Charlson comorbidity index 3 or more; patients diagnosed after 2010; patients from certain regions; patients receiving medical aid; and patients who underwent gynecologic procedures. Multivariable Cox regression analysis showed that brachytherapy when added to curative EBRT was independently associated with better cancer-specific survival (CSS) and overall survival (OS) than curative EBRT only. CONCLUSION: The brachytherapy utilization rate decreased from 2005 to 2013 and varied by region in Korea. Brachytherapy use is independently associated with significantly higher CSS and OS in cervical cancer.

Adverse outcomes after surgeries in patients with liver cirrhosis among Korean population: A population-based study.

BACKGROUND: Patients with liver cirrhosis have an increased risk of in-hospital mortality or postoperative complication after surgery. However, large-scale studies on the prognosis of these patients after surgery are lacking. The aim of the study was to investigate the adverse outcomes of patients with liver cirrhosis after surgery over five years. METHODS AND FINDINGS: We used the Health Insurance Review and Assessment Service-National Inpatient Samples (HIRA-NIS) between 2012 and 2016. In-hospital mortality and hospital stay were analyzed using the data. Mortality rates according to the surgical department were also analyzed. Of the 1,662,887 patients who underwent surgery, 16,174 (1.0%) patients had cirrhosis. The in-hospital mortality (8.0% vs. 1.0%) and postoperative complications such as respiratory (6.0% vs. 5.3%) or infections (2.8% vs. 2.4%) was significantly higher in patients with cirrhosis than in those without cirrhosis. In addition, the total hospitalization period and use of the intensive care unit were significantly higher in patients with liver cirrhosis. In propensity score matching analysis, liver cirrhosis increased the risk of adverse outcome significantly [adjusted OR (aOR) 1.67, 95% CI 1.56-1.79, P<0.001], especially in-hospital mortality. In liver cirrhosis group, presence of decompensation or varices showed significantly increased postoperative complication or mortality. Adverse outcomes in patients with cirrhosis was the highest in patients who underwent otorhinolaryngology surgery (aOR 1.86), followed by neurosurgery (aOR 1.72), thoracic and cardiovascular surgery (aOR 1.56), and plastic surgery (aOR 1.36). CONCLUSION: The adverse outcomes of patients with cirrhosis is significantly high after surgery, despite advances in cirrhosis treatment.