Nationwide Population-based Retrospective Cohort Study Research Articles

Antibiotic usage within the first year of life has a protective effect against ulcerative colitis in South Korea: A nationwide cohort study

BackgroundAntibiotic usage in early life has been proposed as a risk factor for inflammatory bowel disease, especially Crohn's disease. However, most studies were conducted in Western countries. AimsWe evaluated the association between antibiotic usage and the incidence of inflammatory bowel disease in the Asian population. MethodsThis nationwide population-based retrospective cohort study included 2,941,889 South Korean infants born between 2007 and 2015, using the National Health Insurance Service database. We assessed whether antibiotic use was associated with the incidence of inflammatory bowel disease. Additionally, we conducted sensitivity analyses, considering protopathic bias and dietary variables. The Cox proportional hazards model was used. ResultsAmong 2,941,889 infants, 2,566,390 (87 %) used antibiotics within a year after birth. Antibiotic usage within a year, number of antibiotic classes, and cumulative days of usage were shown to decrease the risk of ulcerative colitis. This association was particularly prominent with earlier antibiotic exposure. Penicillin was the only antibiotic class related to the reduced risk. The results were robust after adjusting for dietary variables and considering protopathic effect. ConclusionsAntibiotic exposure during the first year of life, particularly at a younger age, is linked to a reduced risk of early-onset ulcerative colitis in South Korea.

Maternal cigarette smoking before or during pregnancy increases the risk of severe neonatal morbidity after delivery: a nationwide population-based retrospective cohort study

BackgroundThe association of maternal cigarette smoking during pregnancy with severe neonatal morbidity (SNM) is still inconclusive. We aimed to examine the associations of the timing and the intensity of maternal...

HPV-associated cancers among people living with HIV: nationwide population-based retrospective cohort study 2004–21 in Estonia

Abstract Cancers represent the primary cause of mortality among people living with HIV (PLWH). However, comprehensive nationwide data regarding cancer incidence remains limited. Our objective was to evaluate the incidence rates of cancers, particularly those associated with human papillomavirus (HPV), within a nationwide study cohort. Using data from the Estonian Health Insurance Fund and the National Cancer Registry from 2004 to 2021, we calculated standardized incidence ratios (SIRs) for various cancer types among PLWH to compare to the general population with special emphases on HPV-associated cancers. A total of 7011 individuals (65.7% men) diagnosed with HIV were identified. HPV-associated cancers accounted for 21.4% of all incident cancer cases among PLWH. SIRs for HPV-associated cancers were 3.7 [95% confidence interval (CI) 2.2–6.2] among men living with HIV (MLWH) and 5.7 (95% CI 4.0–7.9) among women living with HIV (WLWH). In MLWH, the highest SIRs were for penile 12.5 (95% CI 4.0–38.7), followed by oropharyngeal 3.6 (95% CI 1.7–7.6) and anal–rectal cancers 2.7 (95% CI 1.1–6.4) in comparison to the general population. In WLWH, an increased incidence of cervical (SIR = 5.8, 95% CI 3.9–8.5), oropharyngeal (SIR = 6.1, 95% CI 1.5–24.3), and anal–rectal (SIR = 3.6, 95% CI 1.2–11.2) cancers was observed. A significantly increased risk of AIDS-defining and non-AIDS-defining cancers is reported. We demonstrate a substantially heightened risk of HPV-associated cancers among PLWH compared to the general population, underscoring the imperative for intensified screening and scaled-up vaccination along with improvement in adherence to antiretroviral therapy.

Long-term health outcomes of children born by cesarean section: A nationwide population-based retrospective cohort study in Taiwan

BackgroundTaiwan had high cesarean rate which exceeded the recommended threshold (15%), set by WHO. However, there have not a comprehensive study to discuss the long-term offspring consequences of cesarean section (CS). This study aimed to show whether allergy disorders, obesity and respiratory infection of children are associated with modes of delivery, using the National Health Insurance Research Database (NHIRD) of Taiwan. MethodsThis study used the maternal and child health database of NHIRD. We included the children who birth between 2004 and 2013 and inter-linked the database of the mother and children. The participants were followed until 2018/12/31. We performed a Cox proportional hazards model to identify the association of CS with respiratory tract infection, allergy disorder, and obesity diagnosed in childhood. ResultsCS significantly increased the risk of developed childhood asthma (adjusted hazard ratio [aHR] = 1.03; 95% confidence interval [CI]: 1.02–1.03), allergy rhinitis (aHR = 1.04; 95% CI: 1.04–1.05), atopic dermatitis (aHR = 1.05; 95% CI: 1.04–1.06), respiratory tract infection (aHR = 1.07; 95% CI: 1.06–1.07) and overweight (aHR = 1.29; 95% CI: 1.18–1.40) even after adjusting with confounding factor. Development of food allergy (aHR = 1.13; 95% CI: 0.87–1.47) was not associated with cesarean section. ConclusionThis study indicated that children delivered by CS more commonly developed respiratory tract infections, asthma, allergic rhinitis, atopic dermatitis, obesity than children delivered vaginally. Among these, obesity have a stronger association with cesarean section.

Relationship between smoking experience and risk of suicide mortality in South Korean adults: A nationwide population-based retrospective cohort study

BackgroundKorea has one of the highest suicide rates in the world. Many factors associated with suicidal thoughts or behaviors are known. This study examines the association between 1) smoking status or intensity (pack-years) and 2) risk of suicide mortality in South Korea. MethodsWe analyzed data from 3,966,305 individuals aged ≥20 who underwent health examinations conducted by the South Korean National Health Insurance Service in 2009 and were followed until December 2021. Participants were categorized based on their baseline smoking status and intensity. We performed a Multivariate Cox proportional hazards regression analysis with subgroup analysis by age, sex, body mass index, alcohol consumption, regular exercise, and depression. ResultsDuring an 11.1-year follow-up period, 12,326 individuals died by suicide. Compared with never-smokers, increased hazard ratios of suicide mortality were observed in current smokers (1.64, 95 % CI = 1.56–1.72), but not in ex-smokers. The suicide mortality risk of current smokers increased for all types of smoking intensity without a dose–response relationship. The association between smoking and suicide mortality risk was stronger among women, non-drinkers, adults aged <40 years, non-obese patients, and individuals without depression. LimitationGiven that the study used retrospective data, the causal relationship remains unclear. ConclusionCurrent smoking is associated with a significant increased risk of suicide mortality. Smoking cessation is crucial to prevent suicide, especially among young adults, non-obese individuals, non-drinkers, women, and those without depression. Government policies in South Korea should focus on raising awareness about smoking hazards and providing cessation education to reduce the suicide mortality.

Long-term exposure to air pollution and the risks of venous thromboembolism: a nationwide population-based retrospective cohort study.

To delineate the effects of exposure to air pollution on the risk of venous thromboembolism (VTE). The association between air pollution and arterial occlusive diseases has been well reported in the literature. VTE is the third most common acute cardiovascular syndrome; however, its relationship with exposure to air pollution has been controversial. This study linked data from the Taiwan National Health Insurance Research Database with that from the Taiwan Environmental Protection Administration. Patients who were first admitted for VTE between January 1, 2001, and December 31, 2013, were analyzed. A time-stratified, case-crossover design was employed. Three different exposure periods were defined: exposure for 1month, one quarter, and 1year. Four control periods were designated for each exposure period. The association between exposure to air pollutants and the risk of VTE was tested using logistic regression analysis. Subgroup analyses were also performed, stratified by age, sex, type of VTE, the use of hormone therapy, and level of urbanization at the site of residence. Exposures to particulate matter (PM) smaller than 2.5µm (PM2.5) and those smaller than 10µm (PM10) were associated with higher risks of VTE, with longer exposures associated with higher risk. The concentration of PM2.5 exposure for 1month was linearly associated with a greater risk of VTE up to 28.0µg/m3, beyond which there was no association. PM2.5 exposure for one quarter or 1year remained significantly associated with higher risks of VTE at higher concentrations. The increased risk in VTE associated with exposure to PM2.5 was more prominent in older patients and in patients not under hormone therapy. Similar results were observed for PM10 exposures. Exposure to PM, particularly PM2.5, leads to an increased risk of VTE, with possible accumulative effects. With increased PM production in industrializing countries, the effects of PM on VTE occurrence warrant further attention.

Association between gastrectomy and the risk of type 2 diabetes in gastric cancer survivors: A nationwide cohort study

AimPostprandial glycemic fluctuations after gastrectomy are seen in patients with gastric cancer but, no studies have investigated the association between gastrectomy and type 2 diabetes mellitus (T2DM) in gastric cancer survivors. This study aimed to elucidate the relationship between gastrectomy (total or subtotal) and incident T2DM. In addition, we explored whether vitamin B12 supplementation modulates this risk among patients who have undergone total gastrectomy. MethodsIn this large nationwide population-based retrospective cohort study using the National Health Insurance Service database of South Korea, we identified patients aged >20 years who underwent gastrectomy from 2008 to 2015 (n = 150,074) and age- and sex-matched controls without gastrectomy (n = 301,508). A Cox proportional hazards model was used. ResultsDuring the median follow-up duration of 4.4 years after the 2-year time lag after gastrectomy, of the 78,006 subjects, 4,597 (5.9 %) developed T2DM. Compared with matched controls, the adjusted hazard ratio (AHR[95 % confidence interval]) for T2DM of patients with total gastrectomy was 1.34[1.23;1.47]. The corresponding AHR after subtotal gastrectomy was 0.81[0.76;0.86]. Among the patients with total gastrectomy, the risk of T2DM was significantly increased in those who did not receive any vitamin B12 supplementation (AHR=1.60[1.33;1.92]), whereas the risk of T2DM was lower (close to being statistically significant) in those who received continuous vitamin B12 supplementation after gastrectomy (AHR=0.70[0.49;1.01]). ConclusionThese results show a significantly reduced risk of T2DM in gastric cancer patients undergoing subtotal gastrectomy and a significantly increased risk of T2DM in gastric cancer patients undergoing total gastrectomy, which is mitigated by continuous vitamin B12 supplementation.

Real‐World Incidence of Incident Noninfectious Uveitis in Patients Treated With BRAF Inhibitors: A Nationwide Clinical Cohort Study

To compare the incidence of noninfectious uveitis in skin melanoma or lung cancer patients who received BRAF inhibitors with that in those who received immune checkpoint inhibitors (ICIs) or conventional cytotoxic chemotherapy. Nationwide population-based retrospective clinical cohort study METHODS: From the Health Insurance Review and Assessment Service database of South Korea, we retrospectively defined 77,323 patients with skin melanoma or lung cancer who received BRAF inhibitor therapy (BRAF inhibitor-exposed group; n = 396), ICIs (ICI-exposed group; n = 22,474), or conventional cytotoxic chemotherapy (unexposed group; n = 54,453). We calculated the 1-year cumulative incidence of noninfectious uveitis in each group from the first day of BRAF inhibitor, ICI, or cytotoxic agent administration. During the first year of treatment initiation, the cumulative incidence of uveitis was 0.33%, 0.35%, and 2.27% in the unexposed, ICI-exposed, and BRAF inhibitor-exposed groups, respectively. Adjusted hazard ratios (aHR) indicated a 7.52-fold and 5.68-fold increased risk of uveitis in the BRAF inhibitor-exposed group compared with that in the unexposed and ICI-exposed groups (95% confidence interval [CI] 3.83-14.75, P < 0.001 and 95% CI 2.81-11.47, P < 0.001, respectively). After 1:4 propensity score matching, aHRs showed a 35.51-fold and 15.80-fold increased risk (95% CI 4.49-280.48, P = 0.001 and 95% CI 1.76-141.00, P = 0.014) of uveitis and severe uveitis, respectively, in the BRAF inhibitor-exposed versus unexposed patients. Crossover analysis within the BRAF inhibitor-exposed group showed a 3.71-fold increase in uveitis risk during 1-year post index date in comparison with 1-year prior to index date (95% CI 1.03-13.40, P = 0.046). In the BRAF inhibitor-exposed group, female sex, chronic kidney disease, and melanoma were associated with a trend of increased, albeit nonsignificant, risk of uveitis. Melanoma or lung cancer patients treated with BRAF inhibitors showed significantly higher risk of noninfectious uveitis than patients treated with conventional cytotoxic drugs or ICIs. These findings emphasize the importance of pretreatment patient education on BRAF-inhibitor-associated uveitis risk to enable prompt ophthalmic evaluation and treatment if symptoms arise during drug administration.

Risk of pulmonary embolism and deep vein thrombosis following COVID-19: a nationwide cohort study.

Recent studies elucidate that coronavirus disease 2019 (COVID-19) patients may face a higher risk of cardiovascular complications. This study aimed to evaluate association of COVID-19 with the risk of pulmonary embolism (PE) or deep vein thrombosis (DVT). This nationwide population-based retrospective cohort study included Korean adult citizens between January 2021 and March 2022 from the Korea Disease Control and Prevention Agency COVID-19 National Health Insurance Service cohort. The Fine and Gray's regression with all-cause death as a competing event was adopted to evaluate PE and DVT risks after COVID-19. This study included a total of 1,601,835 COVID-19 patients and 14,011,285 matched individuals without COVID-19. The risk of PE (adjusted hazard ratio [aHR], 6.25; 95% confidence interval [CI], 3.67-10.66; p<0.001) and DVT (aHR, 3.05; 95% CI, 1.75-5.29; p<0.001) was higher in COVID-19 group in individuals without complete COVID-19 vaccination. In addition, individuals with complete COVID-19 vaccination still had a higher risk of COVID-19-related PE (aHR, 1.48; 95% CI, 1.15-1.88; p<0.001). However, COVID-19 was not a significant risk factor for DVT among those with complete COVID-19 vaccination. COVID-19 was identified as an independent factor that elevated PE and DVT risks, especially for individuals without complete COVID-19 vaccination.

Association between Pentosan Polysulfate and Subsequent Maculopathy: Insights from a Nationwide Population-Based Study in Korea

PurposeTo determine the association between pentosan polysulfate (PPS) use and the subsequent development of maculopathy in Asian population. DesignA nationwide population-based retrospective cohort study using the Health Insurance Review and Assessment Service database. Participants103,553 individuals in the PPS user group and 205,792 individuals in the PPS non-user group, all newly diagnosed with cystitis between 2009 and 2020. MethodsThe association between PPS use and maculopathy was evaluated using a time dependent Cox proportional hazard model. Additionally, two sensitivity analyses were conducted by defining PPS users as individuals with an observation period over 6 months from the initial prescription or those with cumulative dose exceeding 9 g, employing the same analysis. Main Outcome MeasuresThe outcome measures included the hazard ratios (HR) representing the association between PPS use and maculopathy. ResultsPPS use was associated with an increased risk of subsequent maculopathy in univariate (HR, 1.7; 95% confidence intervals [CI], 1.66–1.75) and multivariate analysis (HR, 1.34; 95% CI, 1.31–1.38). These results were also confirmed in two sensitivity analyses. The mean cumulative dose of PPS for the cohort was 37.2 ± 76.7 g. ConclusionsIn this nationwide cohort study involving an Asian population, individuals with cystitis using PPS exhibit an increased risk of developing subsequent maculopathy.

Do patients with nephrotic syndrome have an increased risk of osteoporosis? A nationwide population-based retrospective cohort study in Taiwan

ObjectivesTo evaluate whether nephrotic syndrome (NS) and further corticosteroid (CS) use increase the risk of osteoporosis in Asian population during the period January 2000–December 2010.DesignNationwide population-based retrospective cohort study.SettingAll healthcare...

Risk of Subsequent Primary Cancers in Thyroid Cancer Survivors according to the Dose of Levothyroxine: A Nationwide Cohort Study.

Current research has not investigated the effect of thyroid-stimulating hormone suppression therapy with levothyroxine on the risk for developing subsequent primary cancers (SPCs). This study aimed to investigate the association between levothyroxine dosage and the risk for SPCs in thyroid cancer patients. We conducted a nationwide population-based retrospective cohort study form Korean National Health Insurance database. This cohort included 342,920 thyroid cancer patients between 2004 and 2018. Patients were divided into the non-levothyroxine and the levothyroxine groups, the latter consisting of four dosage subgroups according to quartiles. Cox proportional hazard models were performed to evaluate the risk for SPCs by adjusting for variables including cumulative doses of radioactive iodine (RAI) therapy. A total of 17,410 SPC cases were observed over a median 7.3 years of follow-up. The high-dose levothyroxine subgroups (Q3 and Q4) had a higher risk for SPC (adjusted hazard ratio [HR], 1.14 and 1.27; 95% confidence interval [CI], 1.05-1.24 and 1.17- 1.37; respectively) compared to the non-levothyroxine group. In particular, the adjusted HR of stomach (1.31), colorectal (1.60), liver and biliary tract (1.95), and pancreatic (2.48) cancers were increased in the Q4 subgroup. We consistently observed a positive association between high levothyroxine dosage per body weight and risk of SPCs, even after adjusting for various confounding variables. Moreover, similar results were identified in the stratified analyses according to thyroidectomy type and RAI therapy, as well as in a subgroup analysis of patients with good adherence. High-dose levothyroxine use was associated with increased risk of SPCs among thyroid cancer patients regardless of RAI therapy.

The Natural History of Carbapenemase-Producing Enterobacterales: Progression From Carriage of Various Carbapenemases to Bloodstream Infection.

Little is known about the risk of progression from carbapenemase-producing Enterobacterales (CPE) carriage to CPE bloodstream infection (BSI) outside of high-risk settings. We aimed to determine the incidence of CPE BSI among CPE carriers and to assess whether the incidence differs by carbapenemase, species, and setting. We conducted a nationwide population-based retrospective cohort study using national databases. The cohort consisted of all patients in Israel with CPE detected by screening from 1 January 2020 to 10 October 2022. We calculated the cumulative incidence of CPE BSI within 1 year among CPE carriers. We used a competing-risks model with BSI as the outcome and death as the competing risk. The study included 6828 CPE carriers. The cumulative incidence of CPE BSI was 2.4% (95% confidence interval [CI], 2.1-2.8). Compared with Klebsiella pneumoniae carbapenemase (KPC), the subhazard of BSI was lower for New Delhi metallo-β-lactamase (NDM) (adjusted subhazard ratio [aSHR], 0.72; 95% CI, .49-1.05) and oxacillinase-48-like (OXA-48-like) (aSHR, 0.60; 95% CI, .32-1.12) but these differences did not reach statistical significance. Compared with K. pneumoniae, the subhazard of BSI was lower for carriers of carbapenemase-producing Escherichia coli (aSHR, 0.33; 95% CI, .21-.52). The subhazard of BSI was higher among patients with CPE carriage first detected in intensive care units (aSHR, 2.10; 95% CI, 1.27-3.49) or oncology/hematology wards (aSHR, 3.95; 95% CI, 2.51-6.22) compared with medical wards. The risk of CPE BSI among CPE carriers is lower than previously reported in studies that focused on high-risk patients and settings. The risk of BSI differs significantly by bacterial species and setting, but not by carbapenemase.

Elevated prevalence and treatment of sleep disorders from 2011 to 2020: a nationwide population-based retrospective cohort study in Korea

ObjectivesThis study used National Health Insurance claims data from Korea to report the prevalence of sleep disorders and treatment status, including traditional Korean medicine, in the last 10 years.MethodsThis is...

Neuro-Ophthalmic Adverse Events of COVID-19 Infection and Vaccines: A Nationwide Cohort Study.

To evaluate the association of COVID-19 infection and vaccination with neuro-ophthalmic adverse events. In this nationwide population-based retrospective cohort study, 8,498,353 patients were classified into three groups: control, COVID-19 infection, and COVID-19 vaccination. We conducted separate analyses for the early phase (within 60 days) and late phases (61-180 days) to estimate the incidence rates and hazard ratio (HR) for each neuro-ophthalmic adverse event. The adverse events included in this analysis were optic neuritis, papilledema, ischemic optic neuropathy, third nerve palsy, fourth nerve palsy, sixth nerve palsy, facial palsy, nystagmus, ptosis, blepharospasm, anomalies of pupillary function, and Guillain-Barré syndrome/Miller Fisher syndrome (GBS/MFS). Neuro-ophthalmic adverse events other than ptosis and GBS/MFS exhibited no significant increase after COVID-19, and their incidence was extremely low. The incidence rate of ptosis in both phases was significantly higher in patients administered COVID-19 vaccination (HR = 1.65 in the early phase and HR = 2.02 in the late phase) than in the control group. Additionally, BNT162b2 conferred a lower ptosis risk than ChAdOx1. GBS/MFS had a significantly higher incidence rate in the early phase (HR = 5.97) in patients with COVID-19 infection than in the control group. Ptosis was associated with COVID-19 vaccination, particularly with the ChAdOx1 vaccine, while GBS/MFS was associated with COVID-19 infection. In contrast, no association was found between other neuro-ophthalmic adverse events and COVID-19 infection or vaccination. These results may provide helpful insights for diagnosing and treating the neuro-ophthalmological adverse events after COVID-19.

Risk of congestive heart failure and mortality following lymphovenous anastomosis: a nationwide population-based retrospective cohort study.

Lymphovenous anastomosis (LVA) enables lymphatic fluid to drain into the venous system. However, no study has investigated the association between LVA and heart failure (HF) caused by fluid overload in the blood circulating system. The purpose of our study was to determine whether LVA increases the risk of HF and mortality. This nationwide retrospective study evaluated a total of 1400 lymphedema patients who underwent LVA and two control cohorts with 28000 lymphedema who did not undergo LVA and 70000 age-matched and sex-matched participants from the Korean National Health Insurance database were included. Blood pressure, body mass index (BMI), glucose and cholesterol levels, smoking history, and comorbidities were obtained during National Health Insurance Service - Health Screening (NHIS-HealS). The incidence, adjusted risk for HF, and mortality were evaluated. Adjusted HRs for HF were 1.20 (confidence interval [CI], 1.03-1.40) and 1.30 (CI, 1.12-1.50), referenced by the general population control cohort and patients with lymphedema without LVA, respectively. In age, sex, BMI, and smoking status-stratified analyses, heightened risk of HF was evident across all sexes, spanning both young and old age groups, encompassing individuals with various smoking statuses, and those with a BMI of 18.5 or higher. Among these groups, the risk was notably greater in males compared to females, higher in younger individuals as opposed to older ones, and further elevated within the BMI range of 18.5-25. LVA is associated with an increased HF risk, independent of cardiovascular risk factors and associated comorbidities. This association is prominent in participants aged <50 years, in males, and in the normal-to-obese (BMI ≥18.5kg/m 2 ) group. Among patients with lymphedema, LVA did not significantly affect mortality.

Joblessness, decreased income, and disability in intensive care unit survivors of nontraumatic intracranial hemorrhage in South Korea

ObjectivesTo examine the proportions of unemployment, decreased household income, and newly acquired disability, and their impact on long-term mortality after intensive care unit (ICU) admission due to nontraumatic intracranial hemorrhage (IH). Materials and methodsThis nationwide population-based retrospective cohort study enrolled adult patients admitted to the ICU because of nontraumatic IH between 2010 and 2018 in South Korea. Patients who were alive ≥365 days after ICU admission were defined as nontraumatic IH survivors. ResultsIn total, 104,086 nontraumatic IH survivors were included in the final analysis. Among them, 7,225 (6.9 %) experienced job loss, 25,709 (24.7 %) experienced decreased household income, and 20,938 (20.1 %) had newly acquired disabilities, of whom 14,188 (13.6 %) had newly acquired brain disabilities. Male sex, increased duration of intensive care unit stay, comorbid status, hospital admission through the emergency room, nontraumatic intracerebral hemorrhage, receipt of surgery, mechanical ventilatory support, and increased total cost of hospitalization were associated with job loss, decreased household income, and newly acquired disabilities. However, these changes were not significantly associated with 2-year all-cause mortality (adjusted hazard ratio: 1.00, 95 % confidence interval: 0.95, 1.06; P = 0.997). ConclusionsMany nontraumatic IH survivors experienced unemployment, decreased household income, and newly acquired disability one year after ICU admission in South Korea. Some factors were potential risk factors for these changes, but the changes were not associated with 2-year all-cause mortality.

The importance of active rhythm monitoring in patients with renal infarction: Korean national health insurance registry

Abstract Background/Introduction Several studies reported that approximately 50% of renal infraction (RI) is caused by cardioembolic disease, particularly associated with atrial fibrillation (AF). However, in the Korean national health insurance database (NHIS), from 2013 to 2019, the prevalence of AF in patients with RI was only 15%. So, we aimed to analyze the incidence of newly developed AF in RI patients. Method This nationwide population-based retrospective cohort study included 5,200 patients with RI using the NHIS database from 2002 to 2012. We analyzed the incidence rate of AF during 12 months among the patients without previous history of AF. We selected clinical events after three months of RI diagnosis to exclude cases diagnosed by initial screening or with previously missed diagnosis of AF. The definition of RI, AF, and comorbidities use the ICD-10-CM codes. Result During the total follow-up period (median 2.5 years, interquartile range 1.04-4.25), AF occurred in 19.1% of RI patients (n=993). Most cases (n=837, 16.1%) occurred within a year, and the incidence of AF was 3.965 per 10,000 person-year. Patients with newly developed AF had a higher proportion of older age than those without AF (64.1 vs. 57.3 years, P&amp;lt;0.001). The prevalence of comorbidities, including hypertension (HTN), ischemic heart disease (IHD), and heart failure (HF), was higher in those with AF. The independent predictors of AF were age (adjusted hazard ratio [aHR] 1.05, 95% CI 1.04-1.05, P&amp;lt;0.001), male (aHR 1.26, 95% CI 1.09-1.45, P=0.002), body mass index (BMI) (aHR 1.04, 95% CI 1.02-1.06, P &amp;lt;0.001), current smoker (aHR 1.20, 95% CI 1.03-1.40, P =0.023), IHD (aHR 1.20, 95% CI 1.00-1.45, P =0.050) and HF (aHR 1.70, 95% CI 1.25-2.33, P =0.001). Additionally, the incidence of all-cause death was 14.264 per 10,000 person-year during the follow-up period. Conclusion Even if AF is not diagnosed in the initial screening after diagnosis of RI, the physician should consider active rhythm monitoring to detect subclinical AF for optimal management in these patients. Especially it might be helpful to reduce the burden of recurrent embolic events in those with risk factors, such as older age, male, higher BMI, current smoker, IHD, or HF.Cox regression analysisAtrial fibrillation cumulative incidence

Association between lipid levels and the risk of Parkinson's disease in individuals with diabetes mellitus: A nationwide population-based cohort study

IntroductionMany studies have examined the positive association between diabetes mellitus (DM) and the risk of Parkinson's disease (PD). Dyslipidemia has been reported to be prevalent in patients with diabetes; thus, lipid levels and the drugs for dyslipidemia could influence the development of PD in patients with DM. This study aimed to examine the association between lipid levels and the risk of PD in individuals with DM and evaluate whether the association changes with the use of statins. MethodsThis nationwide population-based retrospective cohort study included individuals with DM according to the International Classification of Diseases between 2009 and 2012. Among the 2,361,633 patients with DM followed up for up to 9 years, 17,046 were newly diagnosed with PD. Patients with DM were categorized into quartile groups of total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels. ResultsThere was an inverse association between lipid levels and PD development in the unadjusted model; however, this relationship became less significant after adjusting the use of statins in triglyceride and total cholesterol. In the analysis stratified by statin use, total cholesterol level was associated with decreased PD risk in non-statin users with DM; however, there was no significant association between total cholesterol level and PD risk in statin users. ConclusionWe found an inverse relationship between lipid levels and PD risk in patients with DM, which was influenced by statin use. Future studies about optimal target lipid levels relevant to PD risk considering statin dose in DM patients are needed.

Surgery of the primary tumor in patients with de novo metastatic breast cancer: a nationwide population-based retrospective cohort study in Belgium.

We aimed to assess the impact of surgery of primary tumor in overall survival (OS) of women with de novo metastatic breast cancer. Nationwide, population-based retrospective cohort study of women diagnosed with de novo metastatic breast cancer in Belgium, between Jan/2010-Dec/2014. Data was obtained from the Belgian Cancer Registry and administrative databases. "Surgery" group was defined by surgery of primary tumor up to nine months after diagnosis. We excluded women who did not receive systemic treatment or did not complete nine months follow-up after diagnosis. All the subsequent analyses reporting on overall survival and the stratified outcome analyses were performed based on this nine-month landmark cohort. OS was estimated using Kaplan-Meier method and compared using adjusted Cox proportional hazards models controlling for confounders with 95% confidence intervals (CI). We performed a stratified analysis according to surgery timing and a propensity score matching analysis. 1985 patients, 534 (26.9%) in the "Surgery" and 1451 (73.1%) in the "No Surgery" group. Patients undergoing surgery were younger (p < 0.001), had better performance status (PS) (p < 0.001), and higher proportion of HER2-positive and triple-negative breast cancer (p = 0.012). Median follow-up was 86.0 months (82.6-88.5). Median OS was 60.1 months (57.1-68.2) in the "Surgery" vs. 41.9 months (39.8-44.2) in the "No Surgery" group (adjusted HR 0.56; 0.49-0.64). OS was similar when surgery was performed upfront or after systemic treatment. Propensity score matching analysis confirmed the same findings. Among patients receiving systemic treatment for de novo metastatic breast cancer and surviving nine months or more, those who received surgery of the primary tumor within nine months of diagnosis have longer subsequent survival than those who did not.