Search

Your search keyword '"Agbla, Schadrac C."' showing total 31 results
Start Over Author "Agbla, Schadrac C."
31 results on '"Agbla, Schadrac C."'

2. Feasibility and safety of integrating mass drug administration for helminth control with seasonal malaria chemoprevention among Senegalese children: a randomized controlled, observer-blind trial

Author

Afolabi, Muhammed O., Sow, Doudou, Agbla, Schadrac C., Fall, El Hadji Babacar, Sall, Fatimata Bintou, Seck, Amadou, Manga, Isaac Akhénaton, Mbaye, Ibrahima Marietou, Loum, Mor Absa, Camara, Baba, Niang, Diatou, Gueye, Babacar, Sene, Doudou, Kane, Ndéye M’backé, Diop, Boubacar, Diouf, Awa, Gaye, Ndéye Aida, Diouf, Marie Pierre, Lo, Aminata Colle, Greenwood, Brian, and Ndiaye, Jean Louis A.

Published
2023
Full Text
View/download PDF

3. Estimating cluster-level local average treatment effects in cluster randomised trials with non-adherence

Author

Agbla, Schadrac C., De Stavola, Bianca, and DiazOrdaz, Karla

Subjects
Statistics - Methodology
Abstract

Non-adherence to assigned treatment is a common issue in cluster randomised trials (CRTs). In these settings, the efficacy estimand may be also of interest. Many methodological contributions in recent years have advocated using instrumental variables to identify and estimate the local average treatment effect (LATE). However, the clustered nature of randomisation in CRTs adds to the complexity of such analyses. In this paper, we show that under certain assumptions, the LATE can be estimated via two-stage least squares (TSLS) using cluster-level summaries of outcomes and treatment received. Implementation needs to account for this, as well as the possible heteroscedasticity, to obtain valid inferences. We use simulations to assess the performance of TSLS of cluster-level summaries under cluster-level or individual-level non-adherence, with and without weighting and robust standard errors. We also explore the impact of adjusting for cluster-level covariates and of appropriate degrees of freedom correction for inference. We find that TSLS estimation using cluster-level summaries provides estimates with small to negligible bias and coverage close to nominal level, provided small sample degrees of freedom correction is used for inference, with appropriate use of robust standard errors. We illustrate the methods by re-analysing a CRT in UK primary health settings., Comment: 21 pages, 6 Figures

Published
2018

6. Quality of stepped-wedge trial reporting can be reliably assessed using an updated CONSORT: crowd-sourcing systematic review

Author

Dutton, Susan J., Madurasinghe, Vichithranie, Morgan, Katy, Stuart, Beth, Fielding, Katherine, Cornelius, Victoria, Turner, Elizabeth L., Hooper, Richard, Giraudeau, Bruno, Seed, Paul T., Nickless, Alecia, Grayling, Michael, Prague, Melanie, Kerry, Sally, Bell, Lauren, Watson, Eila, Gafoor, Rafael, Marlin, Nadine, Yorganci, Emel, Smith, Lesley, Mbekwe, Murielle, Teerenstra, Steven, Chan, Claire, Moerbeek, Mirjam, Jacobsen, Pamela, Bond, Simon, Jones, Ben, Preisser, John, Kanaan, Mona, Hewitt, Catherine, Easter, Christina, Pellatt-Higgins, Tracy, Pankhurst, Laura, Agbla, Schadrac C., Eldridge, Sandra, Lerner, Robin G., Leyrat, Clémence, Pilling, Mark, Forman, Julia R., Bhattacharya, Indrani, Magill, Nicholas, Candlish, Jane, McDowell, Cliona, Martin, James, Kristunas, Caroline, Allen, Elizabeth, Seward, Nadine, Nicholls, Elaine, Franklin, Bryony Dean, Hemming, Karla, Carroll, Kelly, Thompson, Jennifer, Forbes, Andrew, and Taljaard, Monica

Published
2019
Full Text
View/download PDF

11. Interactions between fecal gut microbiome, enteric pathogens, and energy regulating hormones among acutely malnourished rural Gambian children

Author

Nabwera, Helen M., primary, Espinoza, Josh L., additional, Worwui, Archibald, additional, Betts, Modupeh, additional, Okoi, Catherine, additional, Sesay, Abdul K., additional, Bancroft, Rowan, additional, Agbla, Schadrac C., additional, Jarju, Sheikh, additional, Bradbury, Richard S., additional, Colley, Mariama, additional, Jallow, Amadou T., additional, Liu, Jie, additional, Houpt, Eric R, additional, Prentice, Andrew M., additional, Antonio, Martin, additional, Bernstein, Robin M, additional, Dupont, Christopher L., additional, and Kwambana-Adams, Brenda A., additional

Published
2021
Full Text
View/download PDF

20. Quality of stepped-wedge trial reporting can be reliably assessed using an updated CONSORT: crowd-sourcing systematic review

Author

Hemming, Karla, primary, Carroll, Kelly, additional, Thompson, Jennifer, additional, Forbes, Andrew, additional, Taljaard, Monica, additional, Dutton, Susan J., additional, Madurasinghe, Vichithranie, additional, Morgan, Katy, additional, Stuart, Beth, additional, Fielding, Katherine, additional, Cornelius, Victoria, additional, Turner, Elizabeth L., additional, Hooper, Richard, additional, Giraudeau, Bruno, additional, Seed, Paul T., additional, Nickless, Alecia, additional, Grayling, Michael, additional, Prague, Melanie, additional, Kerry, Sally, additional, Bell, Lauren, additional, Watson, Eila, additional, Gafoor, Rafael, additional, Marlin, Nadine, additional, Yorganci, Emel, additional, Smith, Lesley, additional, Mbekwe, Murielle, additional, Teerenstra, Steven, additional, Chan, Claire, additional, Moerbeek, Mirjam, additional, Jacobsen, Pamela, additional, Bond, Simon, additional, Jones, Ben, additional, Preisser, John, additional, Kanaan, Mona, additional, Hewitt, Catherine, additional, Easter, Christina, additional, Pellatt-Higgins, Tracy, additional, Pankhurst, Laura, additional, Agbla, Schadrac C., additional, Eldridge, Sandra, additional, Lerner, Robin G., additional, Leyrat, Clémence, additional, Pilling, Mark, additional, Forman, Julia R., additional, Bhattacharya, Indrani, additional, Magill, Nicholas, additional, Candlish, Jane, additional, McDowell, Cliona, additional, Martin, James, additional, Kristunas, Caroline, additional, Allen, Elizabeth, additional, Seward, Nadine, additional, Nicholls, Elaine, additional, and Franklin, Bryony Dean, additional

Published
2019
Full Text
View/download PDF

21. Rapid growth is a dominant predictor of hepcidin suppression and declining ferritin in Gambian infants

Author

Armitage, Andrew E., primary, Agbla, Schadrac C., additional, Betts, Modupeh, additional, Sise, Ebrima A., additional, Jallow, Momodou W., additional, Sambou, Ellen, additional, Darboe, Bakary, additional, Worwui, Archibald, additional, Weinstock, George M., additional, Antonio, Martin, additional, Pasricha, Sant-Rayn, additional, Prentice, Andrew M., additional, Drakesmith, Hal, additional, Darboe, Momodou K., additional, and Kwambana-Adams, Brenda Anna, additional

Published
2019
Full Text
View/download PDF

22. Estimating cluster-level local average treatment effects in cluster randomised trials with non-adherence.

Author

Agbla, Schadrac C, De Stavola, Bianca, DiazOrdaz, Karla, and Austin, Peter

Subjects
*TREATMENT effectiveness, *INSTRUMENTAL variables (Statistics), *DEGREES of freedom, *HETEROSCEDASTICITY, *PRIMARY care, *RESEARCH, *SAMPLE size (Statistics), *RESEARCH methodology, *REGRESSION analysis, *MEDICAL cooperation, *EVALUATION research, *COMPARATIVE studies, *RESEARCH funding, *CLUSTER analysis (Statistics)
Abstract

Non-adherence to assigned treatment is a common issue in cluster randomised trials. In these settings, the efficacy estimand may also be of interest. Many methodological contributions in recent years have advocated using instrumental variables to identify and estimate the local average treatment effect. However, the clustered nature of randomisation in cluster randomised trials adds to the complexity of such analyses. In this paper, we show that the local average treatment effect can be estimated via two-stage least squares regression using cluster-level summaries of the outcome and treatment received under certain assumptions. We propose the use of baseline variables to adjust the cluster-level summaries before performing two-stage least squares in order to improve efficiency. Implementation needs to account for the reduced sample size, as well as the possible heteroscedasticity, to obtain valid inferences. Simulations are used to assess the performance of two-stage least squares of cluster-level summaries under cluster-level or individual-level non-adherence, with and without weighting and robust standard errors. The impact of adjusting for baseline covariates and of appropriate degrees of freedom correction for inference is also explored. The methods are then illustrated by re-analysing a cluster randomised trial carried out in a specific UK primary care setting. Two-stage least squares estimation using cluster-level summaries provides estimates with small to negligible bias and coverage close to nominal level, provided the appropriate small sample degrees of freedom correction and robust standard errors are used for inference. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

27. Impact of the Mycobaterium africanum West Africa 2 Lineage on TB Diagnostics in West Africa: Decreased Sensitivity of Rapid Identification Tests in The Gambia

Author

Ofori-Anyinam, Boatema, primary, Kanuteh, Fatoumatta, additional, Agbla, Schadrac C., additional, Adetifa, Ifedayo, additional, Okoi, Catherine, additional, Dolganov, Gregory, additional, Schoolnik, Gary, additional, Secka, Ousman, additional, Antonio, Martin, additional, de Jong, Bouke C., additional, and Gehre, Florian, additional

Published
2016
Full Text
View/download PDF

28. Host Immune Responses Differ between M. africanum- and M. tuberculosis-Infected Patients following Standard Anti-tuberculosis Treatment

Author

Tientcheu, Leopold D., primary, Haks, Mariëlle C., additional, Agbla, Schadrac C., additional, Sutherland, Jayne S., additional, Adetifa, Ifedayo M., additional, Donkor, Simon, additional, Quinten, Edwin, additional, Daramy, Mohammed, additional, Antonio, Martin, additional, Kampmann, Beate, additional, Ottenhoff, Tom H. M., additional, Dockrell, Hazel M., additional, and Ota, Martin O., additional

Published
2016
Full Text
View/download PDF

30. Hormonal Correlates and Predictors of Nutritional Recovery in Malnourished African Children.

Author

Nabwera, Helen M, Bernstein, Robin M, Agbla, Schadrac C, Moore, Sophie E, Darboe, Momodou K, Colley, Mariama, Jallow, Amadou T, Bradbury, Richard, Karafin, Jennifer, Fulford, Anthony J, and Prentice, Andrew M

Subjects
MALNUTRITION in children, BODY mass index, CHILDREN'S health, DISEASE prevalence, CHILD nutrition
Abstract

Background: Malnourished children show variable growth responses to nutritional rehabilitation. We aimed to investigate whether these differences could be explained by variations in growth and energy-regulating hormones.Methods: Quasi-experimental study: Children aged 6-24 months in rural Gambia were recruited to controls if weight-for-height z-score (WHZ) > -2 (n = 22), moderate acute malnutrition if WHZ < -2 and > -3 (n = 18) or severe acute malnutrition if WHZ < -3 (n = 20). Plasma hormone and salivary CRP levels were determined by ELISA.Results: In univariable analyses, increases in weight-for-age z-score (WAZ) in malnourished children were positively correlated with insulin (F-ratio 7.8, p = 0.006), C-peptide (F-ratio 12.2, p < 0.001) and cortisol (F-ratio 5.0, p = 0.03). In multivariable analysis, only baseline C-peptide (F-ratio 7.6, p = 0.009) predicted the changes in WAZ over 28 days of interventions.Conclusion: In rural Gambian, malnourished children, although it cannot be used in isolation, baseline C-peptide was a predictor of future response to rehabilitation. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results