5 results on '"Snell, K. I. E."'
Search Results
2. External validation of prognostic models to predict stillbirth using International Prediction of Pregnancy Complications (IPPIC) Network database: individual participant data meta-analysis.
- Author
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Allotey, J., Whittle, R., Snell, K. I. E., Smuk, M., Townsend, R., von Dadelszen, P., Heazell, A. E. P., Magee, L., Smith, G. C. S., Sandall, J., Thilaganathan, B., Zamora, J., Riley, R. D., Khalil, A., Thangaratinam, S., Coomarasamy, Arri, Kwong, Alex, Savitri, Ary I., Salvesen, Kjell åsmund, and Bhattacharya, Sohinee
- Subjects
PREGNANCY complications ,PROGNOSTIC models ,STILLBIRTH ,FETAL death ,PREGNANT women ,FETAL monitoring - Abstract
Objective: Stillbirth is a potentially preventable complication of pregnancy. Identifying women at high risk of stillbirth can guide decisions on the need for closer surveillance and timing of delivery in order to prevent fetal death. Prognostic models have been developed to predict the risk of stillbirth, but none has yet been validated externally. In this study, we externally validated published prediction models for stillbirth using individual participant data (IPD) meta-analysis to assess their predictive performance.Methods: MEDLINE, EMBASE, DH-DATA and AMED databases were searched from inception to December 2020 to identify studies reporting stillbirth prediction models. Studies that developed or updated prediction models for stillbirth for use at any time during pregnancy were included. IPD from cohorts within the International Prediction of Pregnancy Complications (IPPIC) Network were used to validate externally the identified prediction models whose individual variables were available in the IPD. The risk of bias of the models and cohorts was assessed using the Prediction study Risk Of Bias ASsessment Tool (PROBAST). The discriminative performance of the models was evaluated using the C-statistic, and calibration was assessed using calibration plots, calibration slope and calibration-in-the-large. Performance measures were estimated separately in each cohort, as well as summarized across cohorts using random-effects meta-analysis. Clinical utility was assessed using net benefit.Results: Seventeen studies reporting the development of 40 prognostic models for stillbirth were identified. None of the models had been previously validated externally, and the full model equation was reported for only one-fifth (20%, 8/40) of the models. External validation was possible for three of these models, using IPD from 19 cohorts (491 201 pregnant women) within the IPPIC Network database. Based on evaluation of the model development studies, all three models had an overall high risk of bias, according to PROBAST. In the IPD meta-analysis, the models had summary C-statistics ranging from 0.53 to 0.65 and summary calibration slopes ranging from 0.40 to 0.88, with risk predictions that were generally too extreme compared with the observed risks. The models had little to no clinical utility, as assessed by net benefit. However, there remained uncertainty in the performance of some models due to small available sample sizes.Conclusions: The three validated stillbirth prediction models showed generally poor and uncertain predictive performance in new data, with limited evidence to support their clinical application. The findings suggest methodological shortcomings in their development, including overfitting. Further research is needed to further validate these and other models, identify stronger prognostic factors and develop more robust prediction models. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]- Published
- 2022
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3. Prediction of pre-eclampsia: review of reviews.
- Author
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Townsend, R., Khalil, A., Premakumar, Y., Allotey, J., Snell, K. I. E., Chan, C., Chappell, L. C., Hooper, R., Green, M., Mol, B. W., Thilaganathan, B., Thangaratinam, S., Snell, K., Hopper, R., Dodds, J., Rogozinska, E., Khan, K., Poston, L., Kenny, L., and Myers, J.
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UTERINE artery ,PLACENTAL growth factor ,CLINICAL prediction rules ,PREGNANCY proteins ,BODY mass index ,PREECLAMPSIA ,BIOMARKERS - Abstract
Copyright of Ultrasound in Obstetrics & Gynecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
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4. External validation of clinical prediction models using big datasets from e-health records or IPD meta-analysis.
- Author
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Riley, R. D., Ensor, J., and Snell, K. I. E.
- Subjects
RESEARCH methodology ,RESEARCH evaluation ,PREDICTIVE tests ,ELECTRONIC health records - Abstract
A review of the article "External Validation of Clinical Prediction Models Using Big Datasets From E-Health Records or IPD Meta-Analysis," by R. D. Riley et al. is presented.
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- 2016
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5. Mortality and implant revision rates of hip arthroplasty in patients with osteoarthritis: registry based cohort study.
- Author
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McMinn DJ, Snell KI, Daniel J, Treacy RB, Pynsent PB, and Riley RD
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- Adolescent, Adult, Aged, Aged, 80 and over, Cementation mortality, Cohort Studies, Female, Humans, Male, Middle Aged, Multivariate Analysis, Prosthesis Failure, Registries, Reoperation statistics & numerical data, Survival Analysis, Young Adult, Arthroplasty, Replacement, Hip methods, Osteoarthritis, Hip mortality, Osteoarthritis, Hip surgery
- Abstract
Objectives: To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing., Design: Cohort study., Setting: National Joint Registry., Population: About 275,000 patient records., Main Outcome Measures: Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity., Results: As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip resurfacings had a higher revision rate than cemented total hip replacements., Conclusions: There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation.
- Published
- 2012
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