1.Predicting renal function using fundus photography: role of confounders
Hyun-Woong PARK ; Hae Ri KIM ; Ki Yup NAM ; Bum Jun KIM ; Taeseen KANG
The Korean Journal of Internal Medicine 2025;40(2):310-320
Background/Aims:
The kidneys and retina are highly vascularized organs that frequently exhibit shared pathologies, with nephropathy often associated with retinopathy. Previous studies have successfully predicted estimated glomerular filtration rates (eGFRs) using fundus photographs. We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas in eGFR prediction.
Methods:
We enrolled patients with fundus photographs and corresponding creatinine measurements taken on the same date. One photograph per eye was randomly selected, resulting in a final dataset of 45,108 patients (88,260 photographs). Data including sex, age, and blood creatinine levels were collected for eGFR calculation using the MDRD and CKD-EPI formulas. EfficientNet B3 models were used to predict each parameter.
Results:
Deep neural network models accurately predicted age and sex using fundus photographs. Sex was identified as a confounding variable in creatinine prediction. The MDRD formula was more susceptible to this confounding effect than the CKD-EPI formula. Notably, the CKD-EPI formula demonstrated superior performance compared to the MDRD formula (area under the curve 0.864 vs. 0.802).
Conclusions
Fundus photographs are a valuable tool for screening renal function using deep neural network models, demonstrating the role of noninvasive imaging in medical diagnostics. However, these models are susceptible to the influence of sex, a potential confounding factor. The CKD-EPI formula, less susceptible to sex bias, is recommended to obtain more reliable results.
2.Predicting renal function using fundus photography: role of confounders
Hyun-Woong PARK ; Hae Ri KIM ; Ki Yup NAM ; Bum Jun KIM ; Taeseen KANG
The Korean Journal of Internal Medicine 2025;40(2):310-320
Background/Aims:
The kidneys and retina are highly vascularized organs that frequently exhibit shared pathologies, with nephropathy often associated with retinopathy. Previous studies have successfully predicted estimated glomerular filtration rates (eGFRs) using fundus photographs. We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas in eGFR prediction.
Methods:
We enrolled patients with fundus photographs and corresponding creatinine measurements taken on the same date. One photograph per eye was randomly selected, resulting in a final dataset of 45,108 patients (88,260 photographs). Data including sex, age, and blood creatinine levels were collected for eGFR calculation using the MDRD and CKD-EPI formulas. EfficientNet B3 models were used to predict each parameter.
Results:
Deep neural network models accurately predicted age and sex using fundus photographs. Sex was identified as a confounding variable in creatinine prediction. The MDRD formula was more susceptible to this confounding effect than the CKD-EPI formula. Notably, the CKD-EPI formula demonstrated superior performance compared to the MDRD formula (area under the curve 0.864 vs. 0.802).
Conclusions
Fundus photographs are a valuable tool for screening renal function using deep neural network models, demonstrating the role of noninvasive imaging in medical diagnostics. However, these models are susceptible to the influence of sex, a potential confounding factor. The CKD-EPI formula, less susceptible to sex bias, is recommended to obtain more reliable results.
3.Predicting renal function using fundus photography: role of confounders
Hyun-Woong PARK ; Hae Ri KIM ; Ki Yup NAM ; Bum Jun KIM ; Taeseen KANG
The Korean Journal of Internal Medicine 2025;40(2):310-320
Background/Aims:
The kidneys and retina are highly vascularized organs that frequently exhibit shared pathologies, with nephropathy often associated with retinopathy. Previous studies have successfully predicted estimated glomerular filtration rates (eGFRs) using fundus photographs. We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas in eGFR prediction.
Methods:
We enrolled patients with fundus photographs and corresponding creatinine measurements taken on the same date. One photograph per eye was randomly selected, resulting in a final dataset of 45,108 patients (88,260 photographs). Data including sex, age, and blood creatinine levels were collected for eGFR calculation using the MDRD and CKD-EPI formulas. EfficientNet B3 models were used to predict each parameter.
Results:
Deep neural network models accurately predicted age and sex using fundus photographs. Sex was identified as a confounding variable in creatinine prediction. The MDRD formula was more susceptible to this confounding effect than the CKD-EPI formula. Notably, the CKD-EPI formula demonstrated superior performance compared to the MDRD formula (area under the curve 0.864 vs. 0.802).
Conclusions
Fundus photographs are a valuable tool for screening renal function using deep neural network models, demonstrating the role of noninvasive imaging in medical diagnostics. However, these models are susceptible to the influence of sex, a potential confounding factor. The CKD-EPI formula, less susceptible to sex bias, is recommended to obtain more reliable results.
4.Predicting renal function using fundus photography: role of confounders
Hyun-Woong PARK ; Hae Ri KIM ; Ki Yup NAM ; Bum Jun KIM ; Taeseen KANG
The Korean Journal of Internal Medicine 2025;40(2):310-320
Background/Aims:
The kidneys and retina are highly vascularized organs that frequently exhibit shared pathologies, with nephropathy often associated with retinopathy. Previous studies have successfully predicted estimated glomerular filtration rates (eGFRs) using fundus photographs. We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas in eGFR prediction.
Methods:
We enrolled patients with fundus photographs and corresponding creatinine measurements taken on the same date. One photograph per eye was randomly selected, resulting in a final dataset of 45,108 patients (88,260 photographs). Data including sex, age, and blood creatinine levels were collected for eGFR calculation using the MDRD and CKD-EPI formulas. EfficientNet B3 models were used to predict each parameter.
Results:
Deep neural network models accurately predicted age and sex using fundus photographs. Sex was identified as a confounding variable in creatinine prediction. The MDRD formula was more susceptible to this confounding effect than the CKD-EPI formula. Notably, the CKD-EPI formula demonstrated superior performance compared to the MDRD formula (area under the curve 0.864 vs. 0.802).
Conclusions
Fundus photographs are a valuable tool for screening renal function using deep neural network models, demonstrating the role of noninvasive imaging in medical diagnostics. However, these models are susceptible to the influence of sex, a potential confounding factor. The CKD-EPI formula, less susceptible to sex bias, is recommended to obtain more reliable results.
5.Predicting renal function using fundus photography: role of confounders
Hyun-Woong PARK ; Hae Ri KIM ; Ki Yup NAM ; Bum Jun KIM ; Taeseen KANG
The Korean Journal of Internal Medicine 2025;40(2):310-320
Background/Aims:
The kidneys and retina are highly vascularized organs that frequently exhibit shared pathologies, with nephropathy often associated with retinopathy. Previous studies have successfully predicted estimated glomerular filtration rates (eGFRs) using fundus photographs. We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas in eGFR prediction.
Methods:
We enrolled patients with fundus photographs and corresponding creatinine measurements taken on the same date. One photograph per eye was randomly selected, resulting in a final dataset of 45,108 patients (88,260 photographs). Data including sex, age, and blood creatinine levels were collected for eGFR calculation using the MDRD and CKD-EPI formulas. EfficientNet B3 models were used to predict each parameter.
Results:
Deep neural network models accurately predicted age and sex using fundus photographs. Sex was identified as a confounding variable in creatinine prediction. The MDRD formula was more susceptible to this confounding effect than the CKD-EPI formula. Notably, the CKD-EPI formula demonstrated superior performance compared to the MDRD formula (area under the curve 0.864 vs. 0.802).
Conclusions
Fundus photographs are a valuable tool for screening renal function using deep neural network models, demonstrating the role of noninvasive imaging in medical diagnostics. However, these models are susceptible to the influence of sex, a potential confounding factor. The CKD-EPI formula, less susceptible to sex bias, is recommended to obtain more reliable results.
6.Prevalence and Associated Factors of Depression and Anxiety Among Healthcare Workers During the Coronavirus Disease 2019 Pandemic:A Nationwide Study in Korea
Shinwon LEE ; Soyoon HWANG ; Ki Tae KWON ; EunKyung NAM ; Un Sun CHUNG ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Ji-Yeon SHIN ; Sang-geun BAE ; Hyun Wook RYOO ; Juhwan JEONG ; NamHee OH ; So Hee LEE ; Yeonjae KIM ; Chang Kyung KANG ; Hye Yoon PARK ; Jiho PARK ; Se Yoon PARK ; Bongyoung KIM ; Hae Suk CHEONG ; Ji Woong SON ; Su Jin LIM ; Seongcheol YUN ; Won Sup OH ; Kyung-Hwa PARK ; Ju-Yeon LEE ; Sang Taek HEO ; Ji-yeon LEE
Journal of Korean Medical Science 2024;39(13):e120-
Background:
A healthcare system’s collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs.
Methods:
A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed.
Results:
A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety.
Conclusion
In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.
7.Triglyceride-Related Parameters and Symptomatic Atherosclerotic Lesions in Patients With Ischemic Stroke
Ki-Woong NAM ; Hyung-Min KWON ; Yong-Seok LEE
Journal of Lipid and Atherosclerosis 2024;13(2):155-165
Objective:
Recently, evidence has suggested that the pathophysiology and risk factors of intracranial atherosclerosis (ICAS) differs from those of extracranial atherosclerosis (ECAS). In addition, novel parameters reflecting metabolic conditions, such as insulin resistance or atherogenic dyslipidemia, based on triglycerides (TG) and other biomarkers, have emerged. In this study, we evaluated the association between TG-related parameters and symptomatic cerebral atherosclerosis in patients with acute ischemic stroke resulting from large artery atherosclerosis (LAA).
Methods:
We assessed consecutive acute LAA-stroke patients between January 2010 and December 2020. Based on the radiological findings, we classified the relevant symptomatic arteries that caused the index stroke into LAA-ICAS and LAA-ECAS. As TGrelated parameters, the atherogenic index of plasma (AIP) and TG-glucose (TyG) index were calculated according to the following formulas: AIP = log10 (TG Level/High-density Lipoprotein Cholesterol Level), TyG Index = Ln (TG Level × Glucose Level/2).
Results:
A total of 519 patients with LAA-stroke were evaluated. In multivariable logistic regression analysis to identify predictors of LAA-ICAS, AIP was significantly associated with LAA-ICAS (adjusted odds ratio [aOR], 3.60; 95% confidence interval [CI], 1.60–8.06). TyG index also showed a statistically significant relationship with LAA-ICAS (aOR, 1.60; 95% CI, 1.11–2.32). However, TG per se did not show a statistical association with LAA-ECAS.
Conclusion
TG-related parameters were more closely associated with stroke by ICAS than by ECAS. The metabolic conditions reflected by the AIP or TyG index, rather than hypertriglyceridemia itself, may play a greater role in determining the relevant vessel causally involved in a stroke.
9.Safety and pharmacokinetic comparison between fenofibric acid 135 mg capsule and 110 mg entericcoated tablet in healthy volunteers
Yu-Bin SEO ; Jae Hoon KIM ; Ji Hye SONG ; WonTae JUNG ; Kyu-Yeol NAM ; Nyung KIM ; Youn-Woong CHOI ; SangMin CHO ; Do-Hyung KI ; Hye Jung LEE ; JungHa MOON ; SeungSeob LEE ; JaeHee KIM ; Jang Hee HONG ; Sunwoo JUNG ; Jin-Gyu JUNG
Translational and Clinical Pharmacology 2023;31(2):95-104
This study aimed to compare the pharmacokinetic (PK) and safety profiles of 2 fenofibric acid formulations under fasting and fed conditions. The reference was a 135 mg capsule, while the test was a 110 mg enteric-coated tablet. This randomized, open-label, two-sequence, two-period crossover phase 1 clinical trial was conducted in healthy Korean men. Sixty participants were enrolled in each of the fasting and feeding groups. Blood samples were collected 72 hours after drug administration. PK parameters were calculated using a noncompartmental method with Phoenix WinNonlin ® . A total of 53 and 51 participants from the fasting and feeding groups, respectively, completed the study. The geometric mean ratio and 90% confidence intervals of the maximum concentration (C max ) and area under the concentration-time curve to the last measurable plasma concentration were 0.9195 (0.8795–0.9614) and 0.8630 (0.8472–0.8791) in the fasting study and 1.0926 (1.0102–1.1818) and 0.9998 (0.9675–1.0332) in the fed study, respectively. The time to reach C max of the enteric-coated tablet compared to that of the capsule was extended by 1 and 3 hours under fasting and fed conditions, respectively. In conclusion, enteric-coated tablets have a higher bioavailability than capsules. In addition, the enteric-coated tablet was smaller than the capsule, making it easier for patients to swallow.
10.Treatment Efficacy of Various Maneuvers for Lateral Canal Benign Paroxysmal Positional Vertigo With Apogeotropic Nystagmus: A Randomized Controlled Trial
Hyun Jin LEE ; Eun-Ju JEON ; Sungil NAM ; Seog-Kyun MUN ; Shin-Young YOO ; Seong Hyun BU ; Jin Woong CHOI ; Jae Ho CHUNG ; Seok Min HONG ; Seung-Hwan LEE ; Min-Beom KIM ; Ja-Won KOO ; Hyun Ji KIM ; Jae-Hyun SEO ; Seong-Ki AHN ; Shi Nae PARK ; Minbum KIM ; Won-Ho CHUNG
Clinical and Experimental Otorhinolaryngology 2023;16(3):251-258
Objectives:
The aim of this study was to determine the most effective treatment approach by comparing the impacts of various otolith reduction techniques in patients with apogeotropic lateral semicircular canal benign paroxysmal positional vertigo (LC-BPPV).
Methods:
We performed a multicenter randomized prospective study from January to December 2015, involving 72 consecutive patients with apogeotropic LC-BPPV. The patients were divided into three treatment groups: therapeutic head-shaking (group A), the Gufoni-Appiani maneuver (group B), and the cupulolith repositioning maneuver (CuRM; group C). Each group underwent evaluation and treatment up to the fourth week. Treatment success was defined as the disappearance of positional vertigo and nystagmus.
Results:
This study included 72 patients (49 male and 23 female), with a mean (±standard deviation) age of 55.4±13.5 years. The mean duration of vertigo experienced prior to treatment was 3.9±4.4 days. The mean latency and duration of nystagmus were 2.7±3.0 seconds and 47.9±15.8 seconds, respectively. The overall treatment frequency was 2.0±0.9. The number of treatments differed significantly among the three groups (P<0.05). After 4 weeks, the success rates for groups A, B, and C were 90.5%, 92.3%, and 100%, respectively. No significant difference was observed in the success rate across treatment methods and periods (P>0.05). However, CuRM was the only method with a 100% treatment success rate.
Conclusion
While no clear difference was observed among the three treatments for LC-BPPV, CuRM was found to be superior to the other approaches in the long term.

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