Retrospective Matched Case-control Study Research Articles

Lumbar localized fat distribution parameters are independent predictors of osteoporotic vertebral compression re-fractures (OVCRFs) following Percutaneous Kyphoplasty (PKP): a retrospective matched case-control study.

To investigate potential risk factors for osteoporotic vertebral compression re-fractures (OVCRFs) following percutaneous kyphoplasty (PKP). Patients who underwent PKP from January 2012 to January 2020 were included in this study within the same institution. Cases were defined as patients who experienced OVCRFs, while controls were matched based on corresponding clinical characteristics from those patients without OVCRFs. The lumbar localized fat distribution parameters, including the fat infiltration ratio (FIR) in muscles [multifidus (MF), erector spinae (ES), paravertebral muscles (PVM), and psoas major (PS)] and subcutaneous fat thickness (SFT), were compared between the two groups through radiological data. And other clinical data that may be relevant were also compared. Independent risk factors for OVCRFs after PKP were identified through a binary logistic regression analysis. A total of 1391 patients who underwent PKP were included in this study. 51 patients were categorized into the re-fracture group, and 102 patients were selected as matched controls from the remaining cohort. There were statistically significant differences between the two groups in metrics including MF-FIR, ES-FIR, PVM-FIR, PS-FIR, bone mineral density (BMD), body-mass index (BMI), SFT, hemoglobin (Hb), albumin (ALB), alkaline phosphatase (ALP), and triglycerides (TG) (P < 0.05). Binary logistic regression analysis demonstrated that PVM-FIR (P = 0.003), SFT (P < 0.001), BMD (P = 0.011), and ALP (P = 0.005) were independent predictors for the occurrence of OVCRFs. This study discovered that lumbar localized fat distribution parameters including PVM-FIR and SFT are independent predictors of OVCRFs. Additionally, BMD and ALP were found to be independent predictors of OVCRFs.

Impact of advanced trauma life support training on 30-day mortality in severely injured patients at a Kenyan tertiary center: a retrospective matched case-control study

IntroductionTrauma is a leading cause of mortality worldwide, particularly in low and middle-income countries (LMICs) like Kenya. This study evaluates the impact of Advanced Trauma Life Support (ATLS) training on 30-day mortality outcomes in severely injured patients at a tertiary care center in Kenya.MethodsA retrospective matched case-control study was conducted at Aga Khan University Hospital, Nairobi. The study included adult patients (≥ 18 years) with polytrauma (Injury Severity Score [ISS] > 15) from 2011 to 2022. Propensity score matching was used to pair 81 post-ATLS cases with 81 pre-ATLS controls based on age and ISS. Data analysis was performed using R Statistical language (version 4.3.0).ResultsThe 30-day mortality rate decreased significantly from 17% (95% CI: 9.4–27.4%) pre-ATLS to 6% (95% CI: 2.0-13.5%) post-ATLS (p = 0.028). No significant differences were found in baseline characteristics between the two groups. Road traffic accidents were the primary cause of trauma in both groups (72% pre-ATLS vs. 78% post-ATLS).ConclusionATLS training significantly reduced 30-day mortality in severely injured patients, demonstrating its effectiveness even in resource-limited settings. Further prospective randomized studies are recommended to confirm these findings and evaluate long-term outcomes.

Synthetic cartilage implant vs. first metatarsophalangeal arthrodesis for the treatment of hallux rigidus.

This study evaluated the outcome of the Cartiva synthetic cartilage implant (SCI) in the treatment of hallux rigidus. In the present retrospective matched case-control study, we compared 18 patients with Cartiva SCI (mean follow-up: 17.7 months) to 18 patients with metatarsophalangeal joint arthrodesis (mean follow-up: 20 months) using multiple function measures, along with four specified visual analog subscales for pain. Pre- and postoperative radiographs were compared, and radiographic abnormalities were documented. We observed no significant differences in function measures between groups. While both groups experienced significant pain reduction, the arthrodesis group reported significantly lower exertion pain than the Cartiva SCI group (p = 0.004). Radiographic abnormalities, including implant site enlargement (6/18, 33.3%), erosive changes of the metatarsal bone (11/18, 61.1%) or articular surfaces (10/18, 55.6%), and bright sclerotic margins (12/18, 66.7%), occurred in the Cartiva SCI group. The present study showed good functional results and a high satisfaction rate after MTP joint arthrodesis, which is considered the gold standard surgical treatment for higher grade hallux rigidus. While the Cartiva SCI group did not show significant differences from the arthrodesis in most aspects of function and clinical scores, the arthrodesis group tended to have better results in terms of satisfaction, residual pain, and revision rate. Even after the short follow-up period, there were some remarkable radiographic findings in the Cartiva SCI group, the long-term effects of which are not yet evident, but which may lead to implant loss. Cartiva SCI has advantages for patients who prioritize postoperative mobility, but the potential risks should be considered in the patient's informed consent. Therefore, the present study highlights the importance of MTP joint arthrodesis for the treatment of hallux rigidus. Level IV - Retrospective matched case-control study.

A retrospective analysis of tuberculosis in livestock farmers in Lahore district, Pakistan.

Mycobacterium tuberculosis is the main cause of tuberculosis in humans, accounting for numerous illnesses and thousands of fatalities globally. Data regarding the association of various risk factors and TB in livestock farmers in Pakistan is scarce. A retrospective matched case-control study of TB cases was performed in Lahore, Pakistan to investigate the potential risk factors that lead to the development of TB in Pakistani livestock farmers. A total of 170 participants were included in the study. The case was matched with control based on neighborhood and the case-control ratio was kept 1:1. Data were statistically analyzed using R version 4.2.1. Conditional logistic regression was conducted to identify biologically and statistically plausible risk factors associated with the TB outcome among livestock farmers. In univariable analysis, 10 risk factors were identified (p < 0.05). Gender, age, being married, family type, living in a big family, BCG vaccination status, history of smoking, working at a cattle farm, co-housing with cattle at night, , consumption of raw milk. The multivariable model identified four risk factors i.e., consumption of raw milk (Odds Ratio [OR]: 7.7; 95% Confidence Interval [CI]: 1.95-30.68), living in big family (OR: 6.2; 95% CI: 1.25-30.82) and working at cattle farm (OR: 4.2; 95% CI: 1.08-16.56), while gender was found to be a protective factor with OR < 1 (OR: 0.06; 95% CI: 0.01-0.26). This study demonstrated that sociodemographic risk factors and exposure to infected cattle can influence the development of TB in farmers.

Clinical characteristics and long-term disease course in patients with Crohn's disease as diagnosed by video capsule endoscopy: a multicenter retrospective matched case-control study.

Video capsule endoscopy is rarely used to diagnose Crohn's disease in patients with negative ileocolonoscopy or cross-sectional image findings. We evaluated clinical characteristics and long-term outcomes of these rare cases. This multicenter study included patients with Crohn's disease from 3 tertiary hospitals from January 2007 to October 2022. Patients with normal findings on ileocolonoscopy and computed tomography (CT)/magnetic resonance (MR) enterography but had ulcerations at the small bowel detected by video capsule endoscopy were included. The controls were patients with abnormal findings on endoscopy or CT/MR enterography. Controls were case-matched in a ratio of 3:1 for sex, calendar year of diagnosis, and age at diagnosis. Among 3,752 patients, 24 (0.6%) were diagnosed with Crohn's disease using video capsule endoscopy findings. The disease location (P< 0.001) and behavior at diagnosis (P= 0.013) of the cases significantly differed from that of controls. The perianal fistula modifier (25.0% vs. 33.3%, P= 0.446) did not differ significantly between the 2 groups. Initial disease activity and C-reactive protein and fecal calprotectin levels were significantly lower in cases versus controls. The median Lewis score was 838 (interquartile range, 393-1,803). Over 10 years of follow-up, the cases showed significantly lower cumulative risk of complicated behavior, biologics use, Crohn's disease-related hospitalization, and surgeries (log-rank test P< 0.05). Patients with Crohn's disease whose lesions were observed only by video capsule endoscopy were rare, and exhibit different clinical characteristics and a more favorable long-term disease course compared to those who were conventionally diagnosed.

COVID-19 infection during pregnancy and risk of early and late spontaneous miscarriages: A matched case-control population-based study.

To evaluate the effect of COVID-19 during the first trimester on the rate of first- and second-trimester miscarriages. Secondary aims include the effect on stillbirths and the correlation between symptom severity and pregnancy outcomes. A retrospective matched case-control population-based study extracted data from electronic medical records of a nationwide database of the second largest healthcare organization that provides medical services to over 2 000 000 patients in Israel. Pregnancy outcomes in COVID-19-positive pregnant patients in 2020 were compared with an age- and gestational-week-matched 1:2 case-control cohort of pre-pandemic pregnant patients that received medical care in 2019. Of 68 485 pregnant women treated in 2020, 2333 were COVID-19-positive during pregnancy: 215 during the first trimester, 791 during the second trimester, and 1327 during the third trimester. We compared these data with the control cohort of 4580 pre-pandemic pregnant patients. The rate of spontaneous miscarriage was significantly higher 146/2187 (6.3%) in COVID-19-positive patients versus 214/4580 (4.7%), (P < 0.01, odds ratio 1.34, 95% confidence interval 1.094-1.691). Most miscarriages occurred during the first trimester in both groups, yet the rates were significantly higher in the study group (5.4% vs 3.8%, P < 0.01). There was no association between COVID-19 severity and miscarriage risk. COVID-19 diagnosis during early pregnancy increased the rate of spontaneous miscarriage in our cohort compared with an age- and gestational-week-matched pre-pandemic control group.

Paper 01: Clinical Outcomes Following ACL Reconstruction with Slope Reducing High-Tibial Osteotomy: A Matched Case-Control Study

Objectives: Despite recent efforts, the reinjury rate following anterior cruciate ligament (ACL) reconstruction remains high, with documented reports of up to 30%. According to retrospective evidence, high posterior tibial slope (≥12°) has been identified as an anatomic risk factor contributing increased graft reinjury rates. Surgeons are therefore exploring the effectiveness of slope reducing high tibial osteotomy (SRO) as a means of modifying this potential risk factor. While cadaveric models suggest that this surgical procedure decreases the forces across the ACL graft, there are few clinical trials examining its’ safety and clinical effectiveness in patient samples. Therefore, the purpose of this study is to compare functional performance and graft reinjury rates between patients undergoing ACL reconstruction surgery with SRO versus matched controls undergoing isolated ACL reconstruction. We hypothesized that patients undergoing ACL reconstruction with SRO would exhibit similar performance outcomes with a low failure rate when compared to their matched counterparts. Methods: A retrospective matched-case control study was conducted in accordance with the ‘Strengthening the Reporting of Observational Studies in Epidemiology’ guidelines for patients undergoing ACL reconstruction (Figure 1), utilizing a single surgeon database (n=1978). The experimental group (ACL+SRO) consisted of patients ages 18-50 years old that were at least 24-months out of ACL reconstruction with a concomitant SRO. Patients were age, sex, and revision-matched to a cohort of individuals undergoing isolated ACL reconstruction. Exclusion criteria consisted of contralateral knee injury (&lt;24 months prior to surgery), isolated coronal-plane high tibial osteotomy, and multiligamentous knee injury. Patient demographics and surgical data were obtained, including pre/postoperative posterior tibial slope (o) for the ACL+SRO group and presurgery activity levels. Data were gathered at return to sports and included knee range of motion, single-leg balance, single-leg hop testing, and self-reported International Knee Documentation Committee and ACL-Return to Sports After Injury (ACL-RSI) scores. Complications and injury surveillance was conducted throughout the postoperative follow-up period. Primary outcome measures included the Single Assessment Numeric Scale (SANE), and graft failure rates at two-years. Secondary outcomes included return to sport rate and level of participation, and postoperative complications (infection, loss of motion, deep vein thrombosis, etc). Generalized Linear Models and chi-square analyses were conducted using SPSS (IBM, Chicago IL) to compare groups with an a-priori alpha level of .05. Results: Of the 1978 patients in the ACL registry, 48 met the study criteria and were included in the analyses (ACL+SRO group, n=24; Isolated ACL group, n=24). Baseline comparisons revealed that the ACL+SRO group had a higher bodyweight (200.9 ±35.1 vs 179.7 ±33.9, P &lt;.001) and subsequent higher body mass index (29.7 ±4.6 vs 26.7 ±5.0, P = .044), Table 1. Additional baseline differences included ACL graft type, and staged procedures ( P &lt; .05, Table 2). The mean preoperative posterior tibial slope was 17.0° ±2.7° and 7.0° ±2.2° following SRO (mean diff: -10.0°, P &lt;.001). Table 3 depicts the comparisons at return to sport, with the ACL+SRO group demonstrating longer time to return ( P &lt; .001) and lower ACL-RSI scores ( P = .027). At 2 years, there were no statistical differences in SANE score (85.3 ±7.3 vs 88.2 ±9.7, P = .349), graft reinjury rate (0.0% vs 0.0%, P = 1.000), rate of return to sports (85.7% vs 91.7%, P = .844), or level of return to sports between groups with 45.8% (n=11) of the ACL+SRO group returning to a level I or II cutting and pivoting sport versus 54.2% (n=13) in the Isolated ACL group ( P = .656). There were no reported postoperative infections or deep vein thromboses in either group (P &gt; .05). Conclusions: The current study suggests that SRO in the setting of ACL reconstruction for large posterior tibial slope deformities is effective at correcting malalignment, restoring objective and self-reported function, and avoiding graft failure out to 2 years. This procedure also holds promise to allow a majority of patients to return to various levels of sporting activities. To our knowledge, this is the first comparative study examining the return to sports and 2-year outcomes of this population to a matched isolated ACL cohort. While these data do provide evidence for ongoing investigation, we recommend the performance of larger clinical trials to confirm these results. [Figure: see text][Figure: see text][Figure: see text][Figure: see text]

Predicting COVID 19-Associated Pulmonary Aspergillosis Risk in Low- and Middle-Income Countries: A Matched Case-Control Study.

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a life-threatening fungal infection. Studies focusing on CAPA in low- and middle-income countries are limited. This retrospective matched case-control study was conducted at a tertiary care center in South India. Cases of CAPA were classified using the 2020 European Confederation of Medical Mycology/International Society for Human and Animal Mycology consensus criteria. A total of 95 cases were matched 1:1 with COVID-19 patients without CAPA. Matching was done based on age and period of admission. Inverse probability weighting was used to account for imbalances in COVID-19 severity and intensive care unit (ICU) admission. Data on demographics, clinical details, microbiologic and radiologic data, and treatment outcomes were collected. A predictive score for CAPA was developed from baseline risk factors. The predictive score identified lymphopenia, European Organisation for Research and Treatment of Cancer risk factors, and broad-spectrum antibiotic use as the main risk factors for CAPA. Positivity for bacterial pathogens in blood or bronchoalveolar lavage samples reduced the risk of CAPA. The predictive model performed well in cross-validation, with an area under the curve value of 82%. CAPA diagnosis significantly increased mortality and shift to ICU. The predictive model derived from the current study offers a valuable tool for clinicians, especially in high-endemic low- and middle-income countries, for the early identification and treatment of CAPA. With further validation, this risk score could improve patient outcomes.

Genetic Variation in ABCB1, ADRB1, CYP3A4, CYP3A5, NEDD4L and NR3C2 Confers Differential Susceptibility to Resistant Hypertension among South Africans.

Resistant hypertension (RHTN) prevalence ranges from 4 to 19% in Africa. There is a paucity of data on the role of genetic variation on RHTN among Africans. We set out to investigate the role of polymorphisms in ABCB1, ADRB1, CYP3A4, CYP3A5, NEDD4L, and NR3C2, on RHTN susceptibility among South Africans. Using a retrospective matched case-control study, 190 RHTN patients (cases: blood pressure (BP) ≥ 140/90 mmHg on ≥3 anti-hypertensives or BP < 140/90 mmHg on >3 anti-hypertensives) and 189 non-RHTN patients (controls: <3 anti-hypertensives, BP < 140/90 or ≥140/90 mmHg), 12 single nucleotide polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), quantitative PCR and Sanger sequencing. Genetic association analyses were conducted using the additive model and multivariable logistic regression. Homozygosity for CYP3A5 rs776746C/C genotype (p = 0.02; OR: 0.44; CI: 0.22-0.89) was associated with reduced risk for RHTN. Homozygous ADRB1 rs1801252G/G (p = 0.02; OR: 3.30; CI: 1.17-10.03) and NEDD4L rs4149601A/A genotypes (p = 0.001; OR: 3.82; CI: 1.67-9.07) were associated with increased risk for RHTN. Carriers of the of ADRB1 rs1801252-rs1801253 G-C haplotype had 2.83-fold odds of presenting with RHTN (p = 0.04; OR: 2.83; CI: 1.05-8.20). These variants that are associated with RHTN may have clinical utility in the selection of antihypertensive drugs in our population.

Risk factors for neonatal hypoxic ischemic encephalopathy and therapeutic hypothermia: a matched case-control study

BackgroundPeripartum asphyxia is one of the main causes of neonatal morbidity and mortality. In moderate and severe cases of asphyxia, a condition called hypoxic-ischemic encephalopathy (HIE) and associated permanent neurological morbidities may follow. Due to the multifactorial etiology of asphyxia, it may be difficult prevent, but in term neonates, therapeutic cooling can be used to prevent or reduce permanent brain damage. The aim of this study was to assess the significance of different antenatal and delivery related risk factors for moderate and severe HIE and the need for therapeutic hypothermia.MethodsWe conducted a retrospective matched case-control study in Helsinki University area hospitals during 2013–2017. Newborn singletons with moderate or severe HIE and the need for therapeutic hypothermia were included. They were identified from the hospital database using ICD-codes P91.00, P91.01 and P91.02. For every newborn with the need for therapeutic hypothermia the consecutive term singleton newborn matched by gender, fetal presentation, delivery hospital, and the mode of delivery was selected as a control. Odds ratios (OR) between obstetric and delivery risk factors and the development of HIE were calculated.ResultsEighty-eight cases with matched controls met the inclusion criteria during the study period. Maternal and infant characteristics among cases and controls were similar, but smoking was more common among cases (aOR 1.46, CI 1.14–1.64, p = 0.003). The incidence of preeclampsia, diabetes and intrauterine growth restriction in groups was equal. Induction of labour (aOR 3.08, CI 1.18–8.05, p = 0.02) and obstetric emergencies (aOR 3.51, CI 1.28–9.60, p = 0.015) were more common in the case group. No difference was detected in the duration of the second stage of labour or the delivery analgesia.ConclusionsSmoking, induction of labour and any obstetric emergency, especially shoulder dystocia, increase the risk for HIE and need for therapeutic hypothermia. The decisions upon induction of labour need to be carefully weighed, since maternal smoking and obstetric emergencies can hardly be controlled by the clinician.

Evaluating risk factors for development of a parastomal hernia: a retrospective matched case-control study

Evaluating risk factors for development of a parastomal hernia: a retrospective matched case-control study

Comparison of early visual outcomes after SMILE using VISUMAX 800 and VISUMAX 500 for myopia: a retrospective matched case–control study

VISUMAX 800 was introduced to improve the patient experience and clinical outcomes of small incision lenticule extraction (SMILE). This was a retrospective, matched, and case–control study (1:2) controlled for preoperative central corneal thickness and refractive error that compared early refractive and visual outcomes after SMILE using VISUMAX 800 and VISUMAX 500 to treat myopia. We included 50 eyes that underwent the VISUMAX 800 SMILE and 100 eyes that underwent the VISUMAX 500 SMILE. SMILE using VISUMAX 800 was performed using the CentraLign aid for vertex centration. Cyclotorsion was controlled by an OcuLign assistant in the VISUMAX 800 group after corneal marking. Corneal higher-order aberrations (HOAs) were evaluated using a Pentacam 1 month after surgery. No differences were observed in the pre- and post-operative refractive and visual outcomes at 1 day, 1 month, and 6 months after surgery. VISUMAX 800 induced less total HOAs than VISUMAX 500 (P = 0.036). No statistically significant differences were observed in the amounts of induced spherical aberrations or vertical and horizontal comas. No differences were observed in the 1 month and 6 months refractive and visual outcomes between two SMILE procedures, except for VISUMAX 800, which resulted in lower postoperative total HOAs than VISUMAX 500.

Risk Factors for and Outcomes Following Early Acquisition of Mycobacterium abscessus Complex After Lung Transplantation.

Lung transplant recipients are at increased risk of Mycobacterium abscessus complex (MABC) acquisition and invasive infection. We analyzed risk factors and outcomes of early post-lung transplant MABC acquisition. We conducted a retrospective matched case-control study of patients who underwent lung transplant from 1/1/2012 to 12/31/2021 at a single large tertiary care facility. Cases had de novo MABC isolation within 90 days post-transplant. Controls had no positive MABC cultures and were matched 3:1 with cases based on age and transplant date. Recipient demographics and pre-/peri-operative characteristics were analyzed, and a regression model was used to determine independent risk factors for MABC acquisition. We also assessed 1-year post-transplant outcomes, including mortality. Among 1145 lung transplants, we identified 79 cases and 237 matched controls. Post-transplant mechanical ventilation for >48 hours was independently associated with MABC acquisition (adjusted odds ratio, 2.46; 95% CI, 1.29-4.72; P = .007). Compared with controls, cases required more days of hospitalization after the MABC index date (28 vs 12 days; P = .01) and had decreased 1-year post-transplant survival (78% vs 89%; log-rank P = .02). One-year mortality appeared highest for cases who acquired M. abscessus subsp. abscessus (31% mortality) or had extrapulmonary infections (43% mortality). In this large case-control study, prolonged post-transplant ventilator duration was associated with early post-lung transplant MABC acquisition, which in turn was associated with increased hospital-days and mortality. Further studies are needed to determine the best strategies for MABC prevention, surveillance, and management.

54 Identifying Geographic Clusters of H. pylori Associated Metastatic Early-Onset Gastric Cancer: A case-control study in Los Angeles

OBJECTIVES/GOALS: More young adults (age &lt;50 years) are diagnosed with metastatic gastric cancer (mGC) every year. We will evaluate the association between environmental risk factors (including historical racial residential segregation) clinical, pathologic, molecular features and H.pylori associated early-onset mGC (mE-GC). METHODS/STUDY POPULATION: This retrospective matched case-control study of patients (1:2 by diagnosis year) with mGC (early-onset [E-GC; &lt;50 years]; vs older-onset [O-GC; &gt;50 years]) from 2000-2022 from the Los Angeles Cancer Surveillance Program (LA-CSP) will be enriched by a chart-abstracted cohort from USC Norris Comprehensive Cancer (NCCC). This annotated database captures sociodemographic, medical, and pathologic features of patients treated for mGC at NCCC. It will link to LA-CSP data exploring neighborhood features (obesity rate, poverty, insurance, access to care, ethnic enclave, historical segregation, etc.) of cases and controls to identify, characterize, and compare geographic “hotspot” neighborhoods of mE-GC. We hypothesize younger Hispanic and Asian patients are at higher risk of H.pylori associated mGC. RESULTS/ANTICIPATED RESULTS: From 2000-2022, 339 patients (mE-GC n = 113; mO-GC n=226) were treated at NCCC. We will have characterized clinical and pathological features of mE-GC vs mO-GC. We determined the proportion of H. pylori associated mE-GC vs mO-GC. We will have established the geographical distribution of patients with mE-GC vs mO-GC to identify high-risk neighborhoods. We will link neighborhood risk factors such as food scarcity, poverty, health care access, ethnic enclaves, to the distinct clinical and pathological features of mE-GC, including H. pylori status. Descriptive statistics, chi-square, t-tests, and multivariable regression will be used to compare mE-GC to mO-GC. After controlling for underlying demographics and tumor features, we anticipate clusters of mE-GC and mO-GC in areas of historical racial segregation. DISCUSSION/SIGNIFICANCE: Linking neighborhood and individual risk factors for mE-GC will inform early detection and prevention efforts for vulnerable individuals in high-risk neighborhoods. Building community partnerships within these neighborhoods is essential for developing interventions targeting H. pylori treatment to reduce health disparities in mE-GC.

Full Thickness Prophylactic Scleral Windows Decrease the Rate of Choroidal Effusion and Drainage Surgery after Ahmed Glaucoma Valve Implantation.

To evaluate the effect of creating a full-thickness prophylactic scleral window (PSW) during Ahmed glaucoma valve (AGV) surgery on the rate of postoperative choroidal effusion and choroidal drainage surgery. In this retrospective matched case-control study, after insertion of AGV tube a PSW was created in one group. The control-matched group had AGV without a PSW. Primary outcome measures were the rate of choroidal effusion formation and choroidal drainage surgery. In total, 544 patients (604 eyes) had undergone AGV implantation from 2013 to 2017. The PSW group consisted of 111 eyes of 111 patients and the control group had 111 eyes of 98 matched patients. There were no differences for systemic diseases, number of anti-glaucoma drugs, aspirin use, smoking, laterality of the operated eye, axial length, and central corneal thickness between the groups. Out of 12 eyes with choroidal effusion, only one belonged to the PSW group (P=0.02). Six eyes in the control group needed choroidal drainage surgery, but none of the eyes in the PSW group required this procedure (P=0.02). No intra- and postoperative issues were observed at the site of the scleral window in the PSW group. PSW creation during AGV surgery is a safe method to decrease the rate of choroidal effusion and choroidal drainage surgery.

P259 Clinical characteristics and long-term disease course in patients with Crohn’s disease diagnosed by video capsule endoscopy; A retrospective multicentre matched case-control study

Abstract Background Video capsule endoscopy (VCE) is a non-invasive and accurate diagnostic modality that allows for direct visualization of the small intestinal mucosa in Crohn’s disease (CD). In rare cases, lesions not detected by other diagnostic modalities in patients suspected to have CD are solely identified through VCE. We aim to evaluate the clinical characteristics and long-term outcomes of these rare cases. Methods A retrospective multicentre matched case-control analysis was conducted in patients with CD across three hospitals in Korea, from January 2007 to April 2023. To perform a matched case-control study, we defined cases (VCE group) as patients with normal findings at colonoscopy and cross-sectional imaging, ultimately diagnosed with CD by VCE; the controls were patients with CD diagnosed with specific findings at endoscopy or cross-sectional imaging (non-VCE group). Controls were matched to cases with a ratio of 3:1 for sex, calendar year of diagnosis, and age at diagnosis. Clinical characteristics and outcomes between the two groups were compared. Results Of the 3,137 patients diagnosed with CD during the study period, 24 were diagnosed solely by VCE. When compared to 72 matched patients with CD, the mean duration from symptom onset to diagnosis did not significantly differ (27.2 months [SD 10.2] vs. 25.3 months [SD 8.9], p=0.394). There was a significant difference in the proportion of Montreal behaviour (p&amp;lt;0.001). In the VCE group, non-stricturing and non-penetrating (B1) type and stricturing (B2) type accounted for 91.7 and 8.3%, respectively. However, there was no significant difference in the perianal fistula modifier (25% vs. 33.3%, p=0.446). Within the VCE group, 45.8% underwent the examination due to abdominal pain with diarrhoea, followed by 25.0% with perianal disease, and 20.8% with unexplained iron deficiency anaemia. Regarding capsule findings, the ileum was mostly involved (87.5%), while the jejunum and duodenum were affected in 70.8 and 16.7% of cases, respectively. Fifteen patients had two or three segments affected. The Median Lewis score was 838 [IQR 393–1803]. Concerning the cumulative incidence of clinical outcomes over 10 years, complicated behaviour, need for biologics, and CD-related hospitalization and surgery were all significantly lower in the VCE group than in the non-VCE group (p&amp;lt;0.005). Conclusion Patients diagnosed with CD solely by VCE are rare. In this study, they exhibited different clinical characteristics and a more favourable long-term disease course compared to the general population of patients with CD. This included a lower incidence of complicated behaviour, reduced need for biologics, and CD-related hospitalization and surgery.

Sialocele and Its Association with Hypercortisolism and Long-Term Glucocorticoid Treatment in Dogs: Retrospective Case-Control Study.

Dogs with sialocele often have concurrent hypercortisolism or are receiving long-term glucocorticoid treatment. However, their association has not been investigated. This retrospective matched case-control study investigated the association between hypercortisolism, long-term glucocorticoid treatment, and sialocele in dogs. We retrospectively reviewed the records from 1 January 2018 to 31 December 2022. Records of 19 dogs diagnosed with sialocele were investigated for hypercortisolism and long-term glucocorticoid treatment. Two age- and breed-matched controls for each sialocele dog (38 dogs) were investigated for the same concurrent diseases. Logistic regression analysis was used. The odds of sialocele in dogs with hypercortisolism were 15.56 times those of dogs without hypercortisolism (p = 0.02; 95% CI: 1.54-156.79). The odds of sialocele in dogs with long-term glucocorticoid treatment (median, 8 months; range, 5-13) were 7.78 times those of dogs without long-term glucocorticoid treatment (p = 0.03; 95% CI: 1.23-49.40). No associations were found between age, sex, body weight, and the presence of sialocele. The results indicate that sialocele was significantly associated with hypercortisolism and long-term glucocorticoid treatment in dogs. Therefore, dogs with hypercortisolism or receiving long-term glucocorticoid therapy should be screened for possible sialocele. Additionally, dogs with sialocele should be identified for concurrent hypercortisolism and prolonged glucocorticoid exposure.

Risk factor for interstitial pregnancy following ipsilateral salpingectomy? A retrospective matched case control study

BackgroundInterstitial pregnancy may still happen even after ipsilateral salpingectomy, resulting in massive hemorrhage. Therefore, the purpose of the study is to identify risk factors associated with interstitial pregnancy following ipsilateral salpingectomy and discuss possible prevention.MethodsWe conducted a retrospective cohort study in a single, large, university-affiliated hospital. Data of 29 patients diagnosed with interstitial pregnancy following ipsilateral salpingectomy from January 2011 to November 2020 were assigned into the case group (IP group). Whereas there were 6151 patients with intrauterine pregnancy after unilateral salpingectomy in the same period. A sample size of 87 control patients was calculated to achieve statistical power (99.9%) and an α of 0.05. The age, BMI and previous salpingectomy side between the two group were adjusted with PSM at a ratio of 1:3. After PSM, 87 intrauterine pregnancy patients were successfully matched to 29 IP patients.ResultsAfter PSM, parous women were more common and intrauterine operation was more frequent in the IP group compared with control group (P<0.05). There was only one patient undergoing IVF-ET in the IP group as compared with 29 cases in the control group (3.4% vs. 33.3%, P<0.05). Salpingectomy was performed on 5 patients in the IP group and 4 patients in the control group due to hydrosalpinx (P<0.05). Logistic regression indicated that hydrosalpinx was the high risk factor of interstitial pregnancy following ipsilateral salpingectomy (OR = 8.175).ConclusionsHydrosalpinx appears to be an independent factor contributing to interstitial pregnancy following ipsilateral salpingectomy in subsequent pregnancy.

1704. Stenotrophomonas maltophilia Infection in a Neonatal Intensive Care Unit (NICU): A Retrospective Study of Risk Factors and Outcomes in an Inner-City Hospital

Abstract Background Stenotrophomonas maltophilia is an aerobic, non-fermenting, Gram-negative bacillus associated with opportunistic and multi-drug resistant infections. The objective of this study was to identify risk factors and outcomes associated with S. maltophilia isolation or infection in a level IIIB neonatal intensive care unit (NICU). Methods This was a retrospective matched case-control study. Cases were matched 2:1 for birth weight, gestational age, and year of NICU admission. The Chi-square test and Fisher’s exact test were used for comparisons of categorical variables. Continuous variables were analyzed with the Mann-Whitney U test. Results A total of 15 S. maltophilia isolates were identified from 15 neonates between January 1, 2008 and April 1, 2020 and matched to 30 controls. Median birth weight and gestational age of the cases was 675 g (IQR, 522.5-997.5 g) and 26 weeks (IQR, 24.86-27.14 weeks), respectively. The trachea was the most frequent site of isolation (9 of 15 isolates); colonization was suspected in 2 cases. Other sites included blood (1 case), conjunctiva (2 cases), and peritoneum (3 cases). The following factors were associated with risk of isolation or infection in cases compared to controls: total days of antibiotic exposure (24 vs 15 days, P = 0.01), total number of antibiotic courses (3 vs 2.5, P = 0.043), total days of broad-spectrum antibiotic exposure (19 vs 9.25 days, P = 0.015), and total days of meropenem exposure (9 vs 3 days, P = 0.008). Total length of NICU stay was significantly longer among cases versus controls (134 vs 68.5 days, P = 0.006). Mortality rate was also significantly higher in cases versus controls (N = 15, 33.33% vs N = 30, 0%; P &amp;lt; 0.001); 3 of 3 infants with peritoneal infection died. All 15 isolates were initially susceptible to levofloxacin, and 14 were susceptible to trimethoprim-sulfamethoxazole. Conclusion Broad-spectrum antibiotic exposure, especially to meropenem, may lead to selection of resistant bacteria and promote S. maltophilia colonization and infection. S. maltophilia isolation or infection was associated with increased length of NICU stay and mortality. Disclosures All Authors: No reported disclosures

High BMI as risk factor in mastectomy in transmasculine individuals: a retrospective matched case-control study

Introduction: Obesity as a risk factor in gender-affirming surgery is a hot topic. Though obesity is considered a risk factor for certain surgical complications, BMI cutoffs may be a barrier to surgical care for transgender individuals. Material and methods: All transgender individuals that underwent gender-affirming mastectomy in our center were retrospectively identified from a departmental database. Every transgender individual with a BMI > 34kg/m2 was matched 1:1 to an individual with a BMI between 18 and 25 kg/m2, based on: surgical technique, surgeon, smoking, resection weight (+/−150 grams), and comorbidity such as diabetes and cardiovascular diseases. A retrospective chart study was conducted, recording demographics, surgical characteristics, short- and long-term complications and reoperations. Complications were ordinally categorized according to the Clavien-Dindo (CD) classification. Outcomes of groups were compared. Results: A total of 53 individuals with BMI > 34 who underwent mastectomy were matched to 53 non-obese individuals according to the abovementioned matching criteria. A total of 44 (83%) non-obese individuals had a complication-free trajectory, versus 23 (43%, p < 0.01) in the obese group. Seroma occurred more frequently in obese individuals (n = 16 (30%) vs 2 (4%), p < 0.01). Looking at de CD rating system, obese individuals experienced more complications overall (p < 0.01). However, complications were mostly CD grade I or II. Secondary surgical chest contour corrections were performed in 9 (17%) obese versus 2 (4%) non-obese individuals. CD grade III complications occurred in 10 (18%) obese individuals and in 4 (8%) non-obese individuals. There were no grade CD grade IV or V complications. Conclusion: Mastectomy in individuals with obesity seems safe with regard to major complications. However, minor complications and revision surgery are significantly more frequently present in these individuals. Preoperative counseling should focus on the higher risk on complications and reoperations.