Impact of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) GFR Estimating Equations on CKD Prevalence and Classification Among Asians

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Protective effect of smoking against pterygium development in men: a nationwide longitudinal cohort study in South Korea

Objective: The present study aimed to evaluate the association between smoking and incident pterygium in adult Korean men. Design: A retrospective nationwide longitudinal cohort. Setting: National Health Insurance database of South Korea. Participants: This study included Korean men (age range: 40-79 years) registered in the Korea National Health Insurance Service database from 2002 through 2013. We compared HRs for pterygium between 90 547 current/past and 90 547 never-smokers via 1:1 propensity-matched analysis. Primary outcome measure: Incident cases of pterygium were identified from the database. Results: Pterygium developed in 5389 (6.0%) never-smokers and 3898 (4.3%) past/current smokers (P<0.001). The incidence of pterygium per 1000 person-years in never-smokers and in past/current smokers was 6.5 and 4.7, respectively (age-adjusted HR, 0.73; 95% CI, 0.70 to 0.76). This protective effect was more pronounced among current smokers than among past smokers (for current smokers: HR, 0.68; 95% CI, 0.65 to 0.71 and for past smokers: HR, 0.85; 95% CI, 0.80 to 0.90). A longer duration of smoking and higher amounts of cigarette consumption were associated with a lower incidence of pterygium. Conclusions: Longitudinally, cigarette smoking was associated with a reduced risk of pterygium, and this protective effect was more pronounced among current smokers than among past smokers.ope

Adopting machine learning to automatically identify candidate patients for corneal refractive surgery

Recently, it has become more important to screen candidates that undergo corneal refractive surgery to prevent complications. Until now, there is still no definitive screening method to confront the possibility of a misdiagnosis. We evaluate the possibilities of machine learning as a clinical decision support to determine the suitability to corneal refractive surgery. A machine learning architecture was built with the aim of identifying candidates combining the large multi-instrument data from patients and clinical decisions of highly experienced experts. Five heterogeneous algorithms were used to predict candidates for surgery. Subsequently, an ensemble classifier was developed to improve the performance. Training (10,561 subjects) and internal validation (2640 subjects) were conducted using subjects who had visited between 2016 and 2017. External validation (5279 subjects) was performed using subjects who had visited in 2018. The best model, i.e., the ensemble classifier, had a high prediction performance with the area under the receiver operating characteristic curves of 0.983 (95% CI, 0.977-0.987) and 0.972 (95% CI, 0.967-0.976) when tested in the internal and external validation set, respectively. The machine learning models were statistically superior to classic methods including the percentage of tissue ablated and the Randleman ectatic score. Our model was able to correctly reclassify a patient with postoperative ectasia as an ectasia-risk group. Machine learning algorithms using a wide range of preoperative information achieved a comparable performance to screen candidates for corneal refractive surgery. An automated machine learning analysis of preoperative data can provide a safe and reliable clinical decision for refractive surgery.ope

Association Between Starting Hemodialysis for End-Stage Renal Disease and Incident Cataract Surgery: A 12-Year Nationwide Cohort Study

PURPOSE: To evaluate incident cataract surgery in subjects who started hemodialysis for end-stage renal disease. METHODS: A nationwide propensity score-matched cohort study was performed by using a 12-year longitudinal national health insurance database of 1,025,340 subjects. The hemodialysis cohort was composed of patients who started hemodialysis between January 2003 and December 2007 (n = 291). The control cohort was composed of randomly selected patients (5 per patient in the hemodialysis cohort; n = 1467) who were matched to the hemodialysis cohort according to a propensity score based on year of hemodialysis initiation, age, sex, residential area, household income, and frequency of medical attention. Each selected patient was followed up until 2013. Cox proportional hazard regression analysis was used to calculate the overall hazard of hemodialysis initiation in regard to incident cataract surgery after adjusting for the above factors, hypertension, and diabetes mellitus. RESULTS: Starting hemodialysis was associated with increased incident cataract surgery (hazard ratio [HR] = 1.79; 95% confidence interval [CI], 1.34-2.41). Diabetes mellitus (HR = 1.68; 95% CI, 1.22-2.32) also increased the incidence of cataract surgery. With respect to age, the effect size of hemodialysis for incident cataract surgery was greater among younger adults (aged <60 years; HR = 5.32; 95% CI, 3.06-9.26) than among older adults (aged ≥60 years; HR = 1.17; 95% CI, 0.79-1.72). CONCLUSIONS: Patients who began hemodialysis for end-stage renal disease were more likely to undergo cataract surgery than control subjects, and this risk was more pronounced in younger patients.ope

Multi-categorical deep learning neural network to classify retinal images: A pilot study employing small database

Deep learning emerges as a powerful tool for analyzing medical images. Retinal disease detection by using computer-aided diagnosis from fundus image has emerged as a new method. We applied deep learning convolutional neural network by using MatConvNet for an automated detection of multiple retinal diseases with fundus photographs involved in STructured Analysis of the REtina (STARE) database. Dataset was built by expanding data on 10 categories, including normal retina and nine retinal diseases. The optimal outcomes were acquired by using a random forest transfer learning based on VGG-19 architecture. The classification results depended greatly on the number of categories. As the number of categories increased, the performance of deep learning models was diminished. When all 10 categories were included, we obtained results with an accuracy of 30.5%, relative classifier information (RCI) of 0.052, and Cohen's kappa of 0.224. Considering three integrated normal, background diabetic retinopathy, and dry age-related macular degeneration, the multi-categorical classifier showed accuracy of 72.8%, 0.283 RCI, and 0.577 kappa. In addition, several ensemble classifiers enhanced the multi-categorical classification performance. The transfer learning incorporated with ensemble classifier of clustering and voting approach presented the best performance with accuracy of 36.7%, 0.053 RCI, and 0.225 kappa in the 10 retinal diseases classification problem. First, due to the small size of datasets, the deep learning techniques in this study were ineffective to be applied in clinics where numerous patients suffering from various types of retinal disorders visit for diagnosis and treatment. Second, we found that the transfer learning incorporated with ensemble classifiers can improve the classification performance in order to detect multi-categorical retinal diseases. Further studies should confirm the effectiveness of algorithms with large datasets obtained from hospitals.ope

Clinical Association of Thyroid Stimulating Hormone Receptor Antibody Levels with Disease Severity in the Chronic Inactive Stage of Graves' Orbitopathy

PURPOSE: To investigate associations between serum thyroid stimulating hormone (TSH) receptor antibody (TRAb) levels and Graves' orbitopathy (GO) activity/severity in chronic-stage GO and compare the performance of two newly-developed TRAb assays (third-generation TSH-binding inhibition immunoglobulin [TBII] assay versus Mc4 thyroid-stimulating immunoglobulin [TSI] bioassay). METHODS: This study is a retrospective review of medical charts and blood tests from Korean GO patients who first visited the departments of ophthalmology and endocrinology, Yonsei University College of Medicine from January 2008 to December 2011, were diagnosed with GO and Graves' hyperthyroidism, and were followed up for ≥18 months. Third-generation M22-TBII and Mc4-TSI assays were performed in the chronic-inactive GO patients in whom euthyroidism status was restored. Patients' GO activity/severity clinical activity scores (CAS), and modified NOSPECS scores were examined for a correlation with TRAb assays. RESULTS: Fifty patients (mean age, 41.3 years; 41 females) were analyzed. The mean duration of Graves' hyperthyroidism symptom was 63 months (range, 18 to 401 months) and that of GO was 46 months (range, 18 to 240 months). All patients had been treated previously with anti-thyroid drugs for a median period of 52.3 months, and two patients underwent either radioiodine therapy or total thyroidectomy. Mean CAS and NOSPECS scores were 0.5 ± 0.9 (standard deviation) and 4.8 ± 3.1, respectively. Mean M22-TBII and Mc4-TSI values were 7.5 ± 10.2 IL/L and 325.9 ± 210.1 specimen-to-reference control ratio. TSI was significantly correlated with NOSPECS score (R = 0.479, p 0.05), because GO inflammatory activity subsided in the chronic stages of GO. CONCLUSIONS: In chronic-inactive GO after euthyroid restoration, GO activity score did not associate with serum levels of TRAb or TBII. However, levels of the functional antibody Mc4-TSI did correlate with GO severity. Therefore, the TSI bioassay is a clinically relevant measure of disease severity even in chronic inactive GO.ope

Factors Associated with Age-related Macular Degeneration: The Korea National Health and Nutrition Examination Survey 2008-2012

Purpose: To evaluate the associations between early/late age-related macular degeneration (AMD) and systemic and ocular parameters using national population-based data. Methods: From 2008 to 2012, a total of 16,897 participants of the Korea National Health and Nutrition Examination Survey underwent ophthalmologic examinations by the Korean Ophthalmological Society. Cases of early and late (neovascular and geographic atrophy) AMD were identified using digital fundus images. Risk factors were identified using logistic regression. Results: Age-standardized prevalence of early and late AMD among subjects aged 40 years and older was 5.5% and 0.6%, respectively. Increasing age was the most significant risk factor for both early and late AMD (adjusted odds ratio [aOR]: 1.09, 95% confidence interval [CI]; 1.07?1.10; aOR: 1.14, 95% CI: 1.10?1.19, respectively). Patients who slept, on average, more than nine hours per day (aOR: 0.68, 95% CI: 0.47?1.00) and who were in the lowest quintile (≤ 38.21 g/dL) of high-density lipoprotein (HDL) cholesterol (aOR: 0.68, 95% CI: 0.51?0.92) were significantly associated with a lower prevalence of early AMD. Increasing spherical equivalent (SE) [aOR]: 0.53 of the first quintile of SE ≤ -1.38 diopters (D), 95% CI: 0.35?0.78; aOR: 1.41 of the fifth quintile of SE ≥ +0.69 D, 95% CI: 1.07?1.86] was associated with a higher prevalence of early AMD. Lower quartile of systolic blood pressure (≤ 110.0 mmHg) was associated with a lower prevalence of neovascular AMD (aOR): 0.25, 95% CI: 0.09?0.67). Conclusions: Aging was the most significant risk factor for both early and late AMD. Lower level of HDL cholesterol, longer duration of sleep, and myopia had protective associations with early AMD, while lower systolic blood pressure had a protective association with neovascular AMD.ope

Four-year nationwide incidence of retinitis pigmentosa in South Korea: a population-based retrospective study from 2011 to 2014

OBJECTIVE: To determine the incidence of retinitis pigmentosa (RP) in South Korea. DESIGN: Nationwide, population-based retrospective study. SETTING: Census population of South Korea PARTICIPANTS: This study involved the entire population of South Korea (n=47 990 761). Patients confirmed as having RP by an ophthalmologist from 1 January 2011 to 31 December 2014 were included. PRIMARY OUTCOME MEASURE: The average incidence of RP during the 4-year study period was estimated using population data from the 2010 Korean census. RESULTS: A total of 3144 (1567 men and 1577 women) patients confirmed as having RP were identified. The average incidence of RP was 1.64 cases/100 000 person-years (95% CI 1.58 to 1.70). The incidence of RP distribution skewed to the left across age groups, with one smaller peak observed in the 20-24-year-old age group (1.24 cases/100 000 person-years) and a larger peak observed in the 65-69-year-old age group (3.26 cases/100 000 person-years). The overall incidence was similar in men and women (1.64 cases/100 000 person-years (95% CI 1.56 to 1.73) for men; 1.63 cases/100 000 person-years (95% CI 1.55 to 1.72) for women). CONCLUSIONS: Our study's estimates of the nationwide population-based incidence of RP in an Asian population will help advance the understanding of the disease onset and allow healthcare systems to plan accordingly.ope

Sociodemographic and health behavioural factors associated with access to and utilisation of eye care in Korea: Korea Health and Nutrition Examination Survey 2008-2012

OBJECTIVE: To determine the sociodemographic and health behavioural factors associated with access to and utilisation of eye care in Korea. DESIGN: Nationwide cross-sectional study METHODS: 25,752 Koreans over the age of 30 were assessed from a national representative survey. We analysed independent variables of self-reporting eye clinic visits through multivariable analyses of sociodemographic factors. The time since the last visit to an eye clinic was used to assess access to and utilisation of eye care. RESULTS: Of the 25,752 respondents, 8237 (32.0%) visited an eye clinic in the past year, 11 028 (42.8%) were seen more than 1 year ago, while 6487 (25.2%) had never seen an ophthalmologist. Eye clinic utilisation was statistically associated with older age, female sex, higher household income, higher education levels, living in an urban area, and having comorbidities including diabetes and hypertension. Middle-aged men between 30 and 49 years were found to be less likely to receive eye care compared to the rest of the population, and the proportion that did plummeted after the financial crisis of 2007. CONCLUSIONS: There is a substantial sociodemographic disparity in eye care utilisation in Korea, and men with low financial income and education level are especially at risk. Use of eye care among middle-aged men has decreased since the global financial crisis that began in 2007, and therefore healthcare policies and public interventions should be targeted at vulnerable groups to promote access to medical care.ope

Factors Associated with Cataract in Korea: A Community Health Survey 2008-2012

PURPOSE: To investigate sociodemographic factors, health behaviors, and comorbidities associated with cataracts in a large, nationally representative Korean sample. MATERIALS AND METHODS: This cross-sectional study included 715554 adults aged 40 years or older who participated in the 2008-2012 Community Health Survey. Significant risk factors were identified using multivariate logistic regression analysis for self-reported cataract, and a nomogram for analysis of cataract risk was generated. RESULTS: Roughly 11% of participants (n=88464) reported being diagnosed with cataracts by a doctor. Age was the most important independent risk factor [adjusted odds ratio (aOR)=1.11, 99% confidence interval (CI), 1.11-1.11 for each increasing year]. Significant comorbidities with descending order of effect size (aOR, 99% CI), included diabetes mellitus (1.78, 1.71-1.85), osteoporosis (1.62, 1.56-1.69), arthritis (1.54, 1.48-1.59), hepatitis B infection (1.46, 1.31-1.63), atopic dermatitis (1.50, 1.33-1.69), angina (1.46, 1.35-1.57), allergic rhinitis (1.45, 1.36-1.55), dyslipidemia (1.38, 1.31-1.45), asthma (1.35, 1.26-1.44), and hypertension (1.23, 1.19-1.28). Subjects who sleep less than 6 hours/day were more likely to have cataract than subjects who sleep more than 9 hours/day as a reference group (aOR=1.22, 99% CI, 1.11-1.34). CONCLUSION: While the most important cataract risk factor was age, the ten comorbidities mentioned above were also significant risk factors. Interestingly, longer duration of sleep was associated with a protective effect against cataract development.ope