Estimation of the Treatment Difference in Multicenter Trials

2004 ◽  
Vol 14 (4) ◽  
pp. 1037-1063 ◽  
Author(s):  
Valerii Fedorov ◽  
Byron Jones ◽  
Matthew Jones ◽  
Anatoly Zhigljavsky
2005 ◽  
Vol 33 (7) ◽  
pp. 50
Author(s):  
JANE SALODOF MACNEIL

1996 ◽  
Vol 76 (06) ◽  
pp. 0893-0896 ◽  
Author(s):  
P Kälebo ◽  
S Ekman ◽  
S Lindbratt ◽  
B I Eriksson ◽  
U Pauli ◽  
...  

SummaryThis study examines inadequacy rates for phlebography in two multicenter trials for the prevention of post-operative DVT and determines inter- and intra-observer variability in evaluating phlebograms. A total of 991 (I) and 385 (II) patients underwent bilateral phlebography in two studies of thromboprophylaxis. Phlebography was performed using a standard method designed to visualize and assess all deep veins. Each vein was scored as normal, DVT or inadequate by both local and central assessment. The study showed low inadequacy rates for phlebograms of 12.2% (121/991) and 6.5% (25/385). Inter-observer agreement (local vs. central assessment) was moderate in both studies (1:74.8%, Kappa-value 0.41; II: 82.6%, Kappa-value 0.51). Good intraobserver agreement (within the central assessment group) was observed (I: 88.8%, Kappa-value 0.75). This study demonstrates low inadequacy rates for phlebograms using a standardized methodology and superior intra-observer agreement compared to inter-observer agreement and supports the importance of central assessment of phlebograms in thromboprophylactic multicenter trials to reduce observer variability.


2020 ◽  
Vol 15 (1) ◽  
pp. 588-596 ◽  
Author(s):  
Jie Meng ◽  
Linyan Xue ◽  
Ying Chang ◽  
Jianguang Zhang ◽  
Shilong Chang ◽  
...  

AbstractColorectal cancer (CRC) is one of the main alimentary tract system malignancies affecting people worldwide. Adenomatous polyps are precursors of CRC, and therefore, preventing the development of these lesions may also prevent subsequent malignancy. However, the adenoma detection rate (ADR), a measure of the ability of a colonoscopist to identify and remove precancerous colorectal polyps, varies significantly among endoscopists. Here, we attempt to use a convolutional neural network (CNN) to generate a unique computer-aided diagnosis (CAD) system by exploring in detail the multiple-scale performance of deep neural networks. We applied this system to 3,375 hand-labeled images from the screening colonoscopies of 1,197 patients; of whom, 3,045 were assigned to the training dataset and 330 to the testing dataset. The images were diagnosed simply as either an adenomatous or non-adenomatous polyp. When applied to the testing dataset, our CNN-CAD system achieved a mean average precision of 89.5%. We conclude that the proposed framework could increase the ADR and decrease the incidence of interval CRCs, although further validation through large multicenter trials is required.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ingvild M. Ulvik ◽  
Terje Sæthre ◽  
Dagmar F. Bunæs ◽  
Stein Atle Lie ◽  
Morten Enersen ◽  
...  

Abstract Background Due to complex morphology and limited access, the cleaning of the furcation area is extremely challenging. Therefore, novel therapeutic approaches need to be tested to potentially overcome debridement limitations. The aim of the present prospective 12-month study was to compare clinical and microbiological effects following erythritol air-polishing versus conventional mechanical debridement of furcation defects in a cohort of periodontal maintenance patients. Methods Twenty patients with grade II mandibular molar furcation defects volunteered to enroll in this single-centre, examiner masked, randomized controlled trial. In a split-mouth study design, two furcation sites in each patient were randomly assigned to either receive subgingival debridement using erythritol air-polishing (test) or conventional ultrasonic/curette debridement (control) at baseline, and at 3, 6, 9 and 12 months. Probing depth, clinical attachment level and bleeding on probing were recorded at 3-month intervals. Subgingival microbiological samples obtained at baseline, 6 and 12 months were analyzed using checkerboard DNA–DNA hybridization. Discomfort from treatment was scored at 12 months using a visual analogue scale. The differences between treatments, and time-points, were tested using multilevel analysis (mixed effect models and robust variance estimates). Results A significant reduction in probing depth took place following both treatments (p < 0.001). Control sites experienced a significant mean gain in clinical attachment level of 0.5 mm (± 0.2) (p = 0.004), whereas a non-significant gain of 0.4 mm (± 0.3) was observed at test sites (p = 0.119). At 6 months, a significant between-treatment difference of 0.8 mm (± 0.4) was observed in favor of the control (p = 0.032). No significant between-treatment differences were observed in microbial load or composition. Notably, at 12 months patients experienced significantly less discomfort following air-polishing compared with control (p = 0.001). Conclusions The 12-month observations indicate that erythritol air-polishing and conventional mechanical debridement both support clinical improvements. A significant between-treatment difference in clinical attachment level was, however, detected in favour of control debridement at 6 months. In terms of patient comfort, erythritol air-polishing is superior. Trial Registration: The clinical trial was retrospectively registered in ClinicalTrial.gov with registration NCT04493398 (07/28/2020).


1984 ◽  
Vol 5 (3) ◽  
pp. 292
Author(s):  
H.J.J. Kerkkamp ◽  
R. van Domburg ◽  
J.G.P. Tijssen ◽  
J. Lubsen
Keyword(s):  

Vaccine ◽  
2007 ◽  
Vol 25 (50) ◽  
pp. 8432-8440 ◽  
Author(s):  
Eduardo Ortega-Barrìa ◽  
Güler Kanra ◽  
Geert Leroux ◽  
Lulu Bravo ◽  
Assad Safary ◽  
...  

2013 ◽  
Vol 26 (3) ◽  
pp. 400-401 ◽  
Author(s):  
Graham W. Clarke ◽  
Zuzana Diamant ◽  
Steven D. Greenaway ◽  
Margaret Rainer ◽  
Elizabeth Allen ◽  
...  
Keyword(s):  

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