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.Characteristics and outcomes of portal vein thrombosis in patients with inflammatory bowel disease in Korea
Ki Jin KIM ; Su-Bin SONG ; Jung-Bin PARK ; June Hwa BAE ; Ji Eun BAEK ; Ga Hee KIM ; Min-Jun KIM ; Seung Wook HONG ; Sung Wook HWANG ; Dong-Hoon YANG ; Byong Duk YE ; Jeong-Sik BYEON ; Seung-Jae MYUNG ; Suk-Kyun YANG ; Chang Sik YU ; Yong-Sik YOON ; Jong-Lyul LEE ; Min Hyun KIM ; Ho-Su LEE ; Sang Hyoung PARK
The Korean Journal of Internal Medicine 2025;40(2):243-250
Background/Aims:
Portal vein thrombosis (PVT) frequently occurs in patients with inflammatory bowel disease (IBD), particularly when influenced by factors such as abdominal infections, IBD flare-ups, or surgical procedures. The implications of PVT range from immediate issues such as intestinal ischemia to long-term concerns including portal hypertension and its complications. However, there is a notable gap in comprehensive studies on PVT in IBD, especially with the increasing incidence of IBD in Asia. This research aimed to evaluate the clinical features and outcomes of PVT in patients with IBD at a leading hospital in South Korea.
Methods:
This retrospective analysis reviewed adult patients diagnosed with both IBD and PVT from 1989 to 2021 at a renowned South Korean medical center. The study focused on patient characteristics, specifics of PVT, administered treatments, and outcomes, all confirmed through enhanced CT scans.
Results:
A total of 78 patients met the study’s criteria. Notably, only 20.5% (16/78) were treated with oral anticoagulants; however, a vast majority (96.2%; 75/78) achieved complete radiographic resolution (CRR). When comparing patients receiving anticoagulants to those who did not, a significant preference for anticoagulant use was observed in cases where the main portal vein was affected, as opposed to just the left or right veins (p = 0.006). However, multivariable analysis indicated that neither anticoagulant use nor previous surgeries significantly impacted CRR.
Conclusions
Patients with IBD and PVT generally had favorable outcomes, regardless of anticoagulant use.
3.Short-term effects of PCSK-9 inhibitors on percutaneous coronary intervention in patients with acute coronary syndrome
Dong Hyun GIM ; In Young CHOI ; Young-Jae KI ; Hyun Kuk KIM ; Sung Soo KIM ; Keun-Ho PARK ; Heesang SONG ; Dong-Hyun CHOI
The Korean Journal of Internal Medicine 2025;40(3):438-448
Background/Aims:
Proprotein-converting enzyme subtilisin-kexin type 9 (PCSK9) inhibitors act more promptly and efficiently than statins and reduce the risk of cardiovascular events in patients with acute coronary syndrome (ACS). This study aimed to assess the short-term effects of perioperative administration of a single-dose PCSK9 inhibitor in patients with ACS.
Methods:
This study included 789 consecutive patients undergoing percutaneous coronary intervention (PCI) for ACS. The primary clinical endpoint was the occurrence of major adverse cardiovascular events (MACEs) within one month, including cardiac death, non-fatal myocardial infarction, unanticipated revascularization, stroke, stent thrombosis, and rehospitalization for ischemic causes or heart failure.
Results:
PCSK9 inhibitors were administered to 201 of 789 patients. MACEs occurred in eight patients (4.0%) in the treated group and 60 patients (10.2%) in the non-treated group for one month (hazard ratio 0.38, 95% confidence interval 0.18 to 0.80, p = 0.010). The benefit of PCSK9 inhibitors in terms of MACEs was greater in the subgroup of patients treated more than 1 hour before PCI than in the subgroup treated less than 1 hour before PCI or treated after PCI and in the non-treated group.
Conclusions
In patients undergoing PCI for ACS, the risk of MACEs was lower in those treated with perioperative single-dose PCSK9 inhibitors than in those in the untreated group. This benefit was especially noticeable in the subgroups treated > 1 hour before PCI than in those treated less than 1 hour before PCI or after PCI, regardless of the clinical presentation of ACS.
4.Force and moment analysis of clear aligners: Impact of material properties and design on premolar rotation
Dong-Woo KIM ; Hyun-Jun LEE ; Ki Beom KIM ; Sung-Hun KIM ; Seong-Sik KIM ; Soo-Byung PARK ; Youn-Kyung CHOI ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):212-223
Objective:
To quantitatively analyze and compare the forces and moments generated by thermoformed polyethylene terephthalate glycol (PETG) and direct-printed TC-85 clear aligners (CAs), with various margin designs, during premolar rotation.
Methods:
In total, 132 CAs were fabricated and divided into four groups (n = 33 per group). Group C consisted of thermoformed PETG aligners with a 2 mm gingival margin. Group E comprised direct-printed TC-85 aligners with equi-gingival margin, whereas Group G utilized direct-printed TC-85 aligners with 2 mm gingival margins.Finally, Group T featured direct-printed TC-85 aligners with an additional 1 mm thickness at the mesial embrasure. The forces and moments were measured using a 6-axis force/moment transducer at 2°, 3°, and 4° of rotation. All measurements were conducted at 37°C to simulate intraoral conditions. Forces were measured in the buccolingual, anteroposterior, and vertical directions, while moments were measured in the mesiodistal, buccolingual, and rotational planes.
Results:
The PETG aligners (Group C) showed significantly increased buccal and posterior force across the rotation angles (P < 0.05), whereas the intrusive force remained consistent. In contrast, the TC-85 aligners maintained consistent forces across all rotation angles.Direct-printed aligners demonstrated significantly lower intrusive forces than PETG aligners (P < 0.001). Group T exhibited reduced unwanted forces while maintaining effective rotational moments. Furthermore, all direct-printed aligners showed more predictable force delivery patterns than thermoformed aligners.
Conclusions
Direct-printed TC-85 aligners demonstrated superior force consistency and reduced unwanted side effects compared with traditional PETG aligners. Although marginal design modifications did not significantly improve rotational efficiency, they effectively reduced unwanted intrusive forces.
5.Immunologic Response and Effects of COVID-19Vaccines in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis
Ki Hyun LEE ; Hyunsue DO ; Jun Yong CHOI ; Yong-Beom PARK ; Sinyoung KIM ; Sang-Won LEE ; Su Jin JEONG
Yonsei Medical Journal 2025;66(5):259-268
Purpose:
The immunological response and adverse effects of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in patients receiving coronavirus disease-2019 (COVID-19) vaccines remain unclear. We aimed to evaluate the effects of these vaccines on AAV disease activity.
Materials and Methods:
We reviewed the medical records of 52 patients with AAV who had received at least second doses of the COVID-19 vaccine and evaluated their immunogenicity by measuring the anti-spike (S) antibody (Ab) titer levels using the Roche Elecsys® immunoassay. Responses to the Birmingham Vasculitis Activity Score (BVAS) tool and 36-Item Short Form Survey before and after vaccination were obtained to assess AAV disease activity. Vaccine reactivity was measured using a standardized questionnaire.
Results:
We enrolled 52 patients with AAV. No differences were found between those who received second and third doses of vaccination in terms of AAV type, disease activity, vaccine type, or the use of immunosuppressive agents, including steroids. The median anti-S Ab titer was 3967.0 after third doses compared to 419.0 after second doses (p=0.001). Except for mycophenolate mofetil (MMF), when immunosuppressants were administered in conjunction with steroids, the Ab titer was higher after the third vaccination than that after the second dose. The BVAS remained unchanged before and after second and third doses. No life-threatening adverse events were reported.
Conclusion
Although COVID-19 vaccine may not produce sufficient antibodies in patients taking MMF, the vaccine did not exacerbate disease activity or cause severe side effects. Therefore, COVID-19 vaccines should be considered in patients with AAV.
6.Breast cancer implant reconstructive surgery and radiotherapy: a retrospective analysis of medical records
Ji Young YUN ; Ki Jung AHN ; Hyunjung KIM ; Hee Yeon KIM ; Tae Hyun KIM ; Kyung Do BYUN ; Ji Sun PARK ; Yunseon CHOI
Annals of Surgical Treatment and Research 2025;108(5):295-301
Purpose:
This study aimed to analyze whether the occurrence of complications increases if radiotherapy (RT) is administered after breast reconstructive surgery using implants.
Methods:
This retrospective study included 80 patients who underwent breast reconstruction using implants, of which 16 (20.0%) underwent RT. Most patients underwent conventional fractionated RT (n = 13), and hypofractionated RT was performed in 3 patients. Most patients (n = 51, 63.8%) underwent delayed reconstruction, which involved implant replacement after tissue expander insertion. Only 29 patients (36.3%) underwent immediate reconstruction simultaneously with breast cancer surgery.
Results:
The median postoperative follow-up was 39.9 months (range, 8.7–120.3 months). Complications occurred in 18 (22.5%); infectionecrosis (n = 8), leakage/rupture (n = 8), and capsular contracture (n = 2). Infectionecrosis is common in patients undergoing RT. Complications occurred in 4 patients (25.0%) who received RT and 14 (21.9%) who did not receive RT, and complications did not significantly increase with RT (P = 0.511). There was no overall difference in complications between the immediate (4 of 29) and delayed (14 of 51) reconstruction groups (P = 0.129). Nine patients underwent reoperation because of complications; 3 (18.8%) received RT and 6 (9.4%) did not receive RT. The reoperation rate did not increase significantly with RT (P = 0.254). There were 3 cases of recurrence, and patients who received RT had no recurrence.
Conclusion
RT did not significantly increase the complication or reoperation rates if reconstructive surgery was performed using implants. Therefore, RT should be performed in patients at a high risk of recurrence.
7.Biportal endoscopic lumbar interbody fusion using a large polyetheretherketone cage: preliminary results
Sang-Min PARK ; Hyun-Jin PARK ; Ki-Han YOU ; Ho-Joong KIM ; Jin S. YEOM
Asian Spine Journal 2025;19(2):252-258
Methods:
Twelve consecutive patients underwent single-level BELIF for lumbar degenerative disease. The technique involves two small portals, one each for endoscopy and instruments. A large PEEK cage was inserted through a posterolateral approach. Clinical outcomes, including a Visual Analog Scale for back and leg pain, the Oswestry Disability Index, and the European Quality of Life-5 Dimensions, were assessed preoperatively and at 3, 6, and 12 months postoperatively. Fusion status was evaluated using computed tomography (CT) at 12 months.
Results:
The mean patient age was 69.1±7.2 years, with operations predominantly at the L4–5 level (83%). The mean operation time was 149.7±37.4 minutes, and the average surgical drainage was 201.4±59.7 mL. All clinical outcome measures showed significant improvement at 12 months (p<0.05). Fusion was achieved in 83.3% of patients. Cage subsidence (>1 mm) occurred in one patient (8.3%). Complications included one case each of incidental durotomy, wrong-site surgery, and wound dehiscence and three cases of asymptomatic hematoma.
Conclusions
BELIF using a large PEEK cage demonstrated promising clinical outcomes and fusion rates. The technique offers enhanced visualization and enables direct neural decompression while minimizing tissue trauma. The use of a large PEEK cage may contribute to improved stability and reduced subsidence risk.
8.Neuroinflammation in Adaptive Immunodeficient Mice with Colitis-like Symptoms
Sung Hee PARK ; Junghwa KANG ; Ji-Young LEE ; Jeong Seon YOON ; Sung Hwan HWANG ; Ji Young LEE ; Deepak Prasad GUPTA ; Il Hyun BAEK ; Ki Jun HAN ; Gyun Jee SONG
Experimental Neurobiology 2025;34(1):34-47
Emerging evidence suggests that systemic inflammation may play a critical role in neurological disorders. Recent studies have shown the connection between inflammatory bowel diseases (IBD) and neurological disorders, revealing a bidirectional relationship through the gut-brain axis.Immunotherapies, such as Treg cells infusion, have been proposed for IBD. However, the role of adaptive immune cells in IBD-induced neuroinflammation remains unclear. In this study, we established an animal model for IBD in mice with severe combined immune-deficient (SCID), an adaptive immune deficiency, to investigate the role of adaptive immune cells in IBD-induced neuroinflammation. Mice were fed 1%, 3%, or 5% dextran sulfate sodium (DSS) for 5 days. We measured body weight, colon length, disease activity index (DAI), and crypt damage. Pro-inflammatory cytokines were measured in the colon, while microglial morphology, neuronal count, and inflammatory cytokines were analyzed in the brain. In the 3% DSS group, colitis symptoms appeared at day 7, with reduced colon length and increased crypt damage showing colitis-like symptoms. By day 21, colon length and crypt damage persisted, while DAI showed recovery. Although colonic inflammation peaked at day 7, no significant increase in inflammatory cytokines or microglial hyperactivation was observed in the brain. By day 21, neuroinflammation was detected, albeit with a slight delay, in the absence of adaptive immune cells. The colitis-induced neuroinflammation model provides insights into the fundamental immune mechanisms of the gut-brain axis and may contribute to developing immune cell therapies for IBD-induced neuroinflammation.
9.Poor Prognosis of Pneumococcal Co-Infection in Hospitalized Patients with COVID-19: A Propensity Score-Matched Analysis
Soyoon HWANG ; Eunkyung NAM ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Nan Young LEE ; Yu Kyung KIM ; Ji Sun KIM ; Han Wook PARK ; Joon Gyu BAE ; Juhwan JEONG ; Ki Tae KWON
Infection and Chemotherapy 2025;57(1):172-178
The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.
10.National trends in surgical treatment and clinical outcomes among patients with aneurysmal subarachnoid hemorrhage in the Republic of Korea
Yung Ki PARK ; Byul-Hee YOON ; Eui-Hyun HWANG ; Jae Hoon KIM ; Hee In KANG ; Yu Deok WON ; Jin Whan CHEONG
Journal of Cerebrovascular and Endovascular Neurosurgery 2025;27(1):19-32
Objective:
In this study, changes in treatment methods and patient prognosis were analyzed using a Korean nationwide medical insurance information database.
Methods:
Patients with subarachnoid hemorrhage who received surgical treatment for cerebral aneurysm from 2005 to 2020 were included. The specific surgery type was classified using the surgical code and according to whether stents were used. Yearly trends in mortality rates and poor prognosis, using tracheostomy as proxy, were analyzed by a simple regression analysis. A multistep logistic regression analysis was performed to evaluate the risk factors of mortality and poor prognosis.
Results:
Overall, 83,587 patients were included. Females were predominant (64.5%). Microsurgical clip usage rate decreased by approximately two-thirds from 78.8% in 2005 to 24.4% in 2020. Contrarily, endovascular treatment proportion gradually increased, and stent-assisted coil embolization rate surpassed microsurgical clip usage rate in 2020 (24.6% vs. 24.4%). In the multivariate analysis, endovascular treatment correlated positively with 3-month mortality (hazard ratio [HR]: 1.13, 95% confidence interval [CI]: 1.07–1.19, P<0.0001), although correlated negatively with poor prognosis (tracheostomy) (HR: 0.93, 95% CI: 0.89–0.98, P=0.0050).
Conclusions
According to the treatment trend analysis, during the 16 years studied, for patients with subarachnoid hemorrhage due to ruptured cerebral aneurysm, the endovascular treatment rate increased rapidly and stent-assisted coil embolization rate surpassed that of microsurgical clip ligation. Diversification of treatment methods has led to a decrease in mortality and improved prognosis.

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