The Wilcoxon rank sum test is widely used for two-group comparisons for nonnormal data. An assumption of this test is independence of sampling units both between and within groups. In ophthalmology, data are often collected on two eyes of an individual, which are highly correlated. In ophthalmological clinical trials, randomization is usually performed at the subject level, but the unit of analysis is the eye. If the eye is used as the unit of analysis, then a modification to the usual Wilcoxon rank sum variance formula must be made to account for the within-cluster dependence. For some clustered data designs, where the unit of analysis is the subunit, group membership may be defined at the subunit level. For example, in some randomized ophthalmologic clinical trials, different treatments may be applied to fellow eyes of some patients, while the same treatment may be applied to fellow eyes of other patients. In general, binary eye-specific covariates may be present (scored as exposed or unexposed) and one wishes to compare nonnormally distributed outcomes between exposed and unexposed eyes using the Wilcoxon rank sum test while accounting for the clustering. In this article, we present a corrected variance formula for the Wilcoxon rank sum statistic in the setting of eye (subunit)-specific covariates. We apply it to compare ocular itching scores in ocular allergy patients between eyes treated with active versus placebo eye drops, where some patients receive the same eye drop in both eyes, while other patients receive different eye drops in fellow eyes. We also present comparisons between the clustered Wilcoxon test and each of the signed rank tests and mixed model approaches and show dramatic differences in power in favor of the clustered Wilcoxon test for some designs.
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Hernia
January 2025
Department of Surgery, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1259, New York, NY, 10029, USA.
Purpose: While surgeons agree that perioperative field blocks should be performed for open inguinal hernia surgery, there lacks consensus in the minimally invasive context. Prior small-scale randomized trials study pain scores only up to 24 h postoperatively. Thus, we sought to investigate the analgesic benefits of a bupivacaine transversus abdominis plane (TAP) block in the first 4 postoperative days.
View Article and Find Full Text PDFAnimals (Basel)
January 2025
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, 1008 West Hazelwood Drive, Urbana, IL 61802, USA.
Cardiac troponin-I (cTnI) is a highly sensitive and specific marker of myocardial injury detectable in plasma by immunoassay techniques. Inclusion criteria over a 3-year period required a diagnosis of cardiac disease accompanied by electrocardiographic (ECG) and cardiac ultrasound examinations (n = 23) in adult horses (≥2 years of age). A second group of normal adult ponies (n = 12) was studied as a reference group.
View Article and Find Full Text PDFSurg Endosc
January 2025
Department of Surgery, University of Pennsylvania, 800 Walnut St 20th Floor, Philadelphia, PA, 19107, USA.
Introduction: Despite remarkable progress, gender inequality in medicine remains a significant issue. This disparity extends beyond clinical practices and educational programs; it is also evident in the recognition and awards received by surgeons. Underrepresentation of women in Surgical Society awards is a multi-layered issue that needs a holistic approach since these awards are used to hire, promote, and advance surgeons.
View Article and Find Full Text PDFZhonghua Wai Ke Za Zhi
January 2025
Department of Thoracic Surgery, Anhui Provincial Hospital Affiliated with Anhui Medical University,Hefei230001, China.
To explore the operioperative and long-term outcomes of inflatable mediastinoscopic resection of esophageal carcinoma (IVMTE) and minimally invasive Mckeown resection of esophageal carcinoma (MIME) in early esophageal cancer. This is a retrospective cohort study. A retrospectively analysis was conducted on 176 patients with cT1N0M0 esophageal cancer who underwent IVMTE or MIME at the Department of Thoracic Surgery, Anhui Provincial Hospital Affiliated with Anhui Medical University from April 2017 to April 2019.
View Article and Find Full Text PDFMagn Reson Imaging
January 2025
Department of Radiology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang Uygur Autonomous Region, China. Electronic address:
3D BFFE and TRANCE can provide a visualization of pulmonary vessels without injection of contrast agent. T-SLIP can observe a large area of vessels using an arterial spin labeling technique. 3D BFFE and TRANCE with two T-SLIP placement strategies were compared on pulmonary artery imaging.
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