Sarah A Walker

Summary

Affiliation: National Institute for Medical Research
Country: UK

Publications

  1. ncbi Mortality in the year following antiretroviral therapy initiation in HIV-infected adults and children in Uganda and Zimbabwe
    A Sarah Walker
    MRC Clinical Trials Unit, London, UK
    Clin Infect Dis 55:1707-18. 2012
  2. ncbi Characterisation of Clostridium difficile hospital ward-based transmission using extensive epidemiological data and molecular typing
    A Sarah Walker
    National Institute for Health Research Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, United Kingdom
    PLoS Med 9:e1001172. 2012
  3. ncbi Clustering based on adherence data
    Sylvia Kiwuwa-Muyingo
    School of Health Sciences, University of Tampere, Finland
    Epidemiol Perspect Innov 8:3. 2011
  4. ncbi An efficient record linkage scheme using graphical analysis for identifier error detection
    John M Finney
    NIHR Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK
    BMC Med Inform Decis Mak 11:7. 2011
  5. ncbi Daily co-trimoxazole prophylaxis in severely immunosuppressed HIV-infected adults in Africa started on combination antiretroviral therapy: an observational analysis of the DART cohort
    A S Walker
    MRC Clinical Trials Unit, London, UK
    Lancet 375:1278-86. 2010
  6. ncbi The impact of daily cotrimoxazole prophylaxis and antiretroviral therapy on mortality and hospital admissions in HIV-infected Zambian children
    A Sarah Walker
    MRC Clinical Trials Unit, London, United Kingdom
    Clin Infect Dis 44:1361-7. 2007
  7. ncbi Routine versus clinically driven laboratory monitoring of HIV antiretroviral therapy in Africa (DART): a randomised non-inferiority trial
    P Mugyenyi
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    Lancet 375:123-31. 2010
  8. ncbi The evolution of HIV-1 reverse transcriptase in route to acquisition of Q151M multi-drug resistance is complex and involves mutations in multiple domains
    Jean L Mbisa
    Virus Reference Department, Microbiology Services, Colindale, Health Protection Agency, London, UK
    Retrovirology 8:31. 2011
  9. ncbi First-line antiretroviral therapy with a protease inhibitor versus non-nucleoside reverse transcriptase inhibitor and switch at higher versus low viral load in HIV-infected children: an open-label, randomised phase 2/3 trial
    Abdel Babiker
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    Lancet Infect Dis 11:273-83. 2011
  10. ncbi Lamivudine/abacavir maintains virological superiority over zidovudine/lamivudine and zidovudine/abacavir beyond 5 years in children
    H Green
    MRC Clinical Trials Unit, 222 Euston Road, London, NW1 2DA, UK
    AIDS 21:947-55. 2007

Detail Information

Publications46

  1. ncbi Mortality in the year following antiretroviral therapy initiation in HIV-infected adults and children in Uganda and Zimbabwe
    A Sarah Walker
    MRC Clinical Trials Unit, London, UK
    Clin Infect Dis 55:1707-18. 2012
    ..However, the specific patterns of changing risk and causes of death have rarely been investigated in adults, nor compared with children in low-income countries...
  2. ncbi Characterisation of Clostridium difficile hospital ward-based transmission using extensive epidemiological data and molecular typing
    A Sarah Walker
    National Institute for Health Research Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, United Kingdom
    PLoS Med 9:e1001172. 2012
    ..This study aimed to investigate ward-based transmission of C. difficile, by subdividing outbreaks into distinct lineages defined by multi-locus sequence typing (MLST)...
  3. ncbi Clustering based on adherence data
    Sylvia Kiwuwa-Muyingo
    School of Health Sciences, University of Tampere, Finland
    Epidemiol Perspect Innov 8:3. 2011
    ..The new approach is illustrated and shown to be useful with a simple analysis of a data set from the DART (Development of AntiRetroviral Therapy in Africa) trial in Uganda and Zimbabwe...
  4. ncbi An efficient record linkage scheme using graphical analysis for identifier error detection
    John M Finney
    NIHR Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK
    BMC Med Inform Decis Mak 11:7. 2011
    ..It is now common to be required to link very large numbers of records, often containing various combinations of theoretically unique identifiers, such as NHS numbers, which are both incomplete and error-prone...
  5. ncbi Daily co-trimoxazole prophylaxis in severely immunosuppressed HIV-infected adults in Africa started on combination antiretroviral therapy: an observational analysis of the DART cohort
    A S Walker
    MRC Clinical Trials Unit, London, UK
    Lancet 375:1278-86. 2010
    ..We estimated the effect of prophylaxis after ART initiation in adults...
  6. ncbi The impact of daily cotrimoxazole prophylaxis and antiretroviral therapy on mortality and hospital admissions in HIV-infected Zambian children
    A Sarah Walker
    MRC Clinical Trials Unit, London, United Kingdom
    Clin Infect Dis 44:1361-7. 2007
    ..Data on the population effectiveness of cotrimoxazole prophylaxis and antiretroviral therapy (ART) in human immunodeficiency virus (HIV)-infected African children are few...
  7. ncbi Routine versus clinically driven laboratory monitoring of HIV antiretroviral therapy in Africa (DART): a randomised non-inferiority trial
    P Mugyenyi
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    Lancet 375:123-31. 2010
    ..This trial investigated whether routine toxicity and efficacy monitoring of HIV-infected patients receiving ART had an important long-term effect on clinical outcomes in Africa...
  8. ncbi The evolution of HIV-1 reverse transcriptase in route to acquisition of Q151M multi-drug resistance is complex and involves mutations in multiple domains
    Jean L Mbisa
    Virus Reference Department, Microbiology Services, Colindale, Health Protection Agency, London, UK
    Retrovirology 8:31. 2011
    ..In this study we examined the genotypic, phenotypic and fitness correlates associated with the development of Q151M MDR in the absence of viral load monitoring...
  9. ncbi First-line antiretroviral therapy with a protease inhibitor versus non-nucleoside reverse transcriptase inhibitor and switch at higher versus low viral load in HIV-infected children: an open-label, randomised phase 2/3 trial
    Abdel Babiker
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    Lancet Infect Dis 11:273-83. 2011
    ..We assess the long-term outcome of protease inhibitor and non-nucleoside reverse transcriptase inhibitor (NNRTI) first-line ART and viral load switch criteria in children...
  10. ncbi Lamivudine/abacavir maintains virological superiority over zidovudine/lamivudine and zidovudine/abacavir beyond 5 years in children
    H Green
    MRC Clinical Trials Unit, 222 Euston Road, London, NW1 2DA, UK
    AIDS 21:947-55. 2007
    ..To describe the long-term efficacy over 5 years of regimens including combinations of abacavir, lamivudine and/or zidovudine in previously untreated children in the PENTA 5 trial...
  11. ncbi Age as a determinant of survival in HIV infection
    A G Babiker
    MRC Clinical Trials Unit, 222 Euston Rd, NW1 2DA, London, UK
    J Clin Epidemiol 54:S16-21. 2001
    ....
  12. ncbi PRION-1 scales analysis supports use of functional outcome measures in prion disease
    S Mead
    MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, and National Prion Clinic, National Hospital for Neurology and Neurosurgery, UCLH NHS Trust, Queen Square, London, UK
    Neurology 77:1674-83. 2011
    ..Although there are several limitations to the usefulness of survival as an outcome measure, there have been no comprehensive studies of alternatives...
  13. ncbi Residual activity of two HIV antiretroviral regimens prescribed without virological monitoring
    D T Dunn
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, United Kingdom
    Antimicrob Agents Chemother 55:4575-80. 2011
    ..This information should be considered in future treatment guidelines relevant to resource-poor settings...
  14. ncbi The relationship between HIV seroconversion illness, HIV test interval and time to AIDS in a seroconverter cohort
    F Tyrer
    MRC Clinical Trials Unit, London, UK
    Epidemiol Infect 131:1117-23. 2003
    ..76, 95% CI 4.75-9.62). Time to AIDS was significantly faster (P = 0.01) in those with a short test interval. The HIV test interval is a useful replacement for information on seroconversion illness in studies of HIV disease progression...
  15. ncbi Nevirapine clearance from plasma in African adults stopping therapy: a pharmacokinetic substudy
    Ben Kikaire
    MRC UVRI Uganda Research Unit on AIDS, Entebbe, Uganda
    AIDS 21:733-7. 2007
    ..To measure nevirapine elimination in African adults undertaking a structured treatment interruption (STI) in the DART trial...
  16. ncbi Nevirapine concentrations in HIV-infected children treated with divided fixed-dose combination antiretroviral tablets in Malawi and Zambia
    Jane C Ellis
    Department of Paediatrics, College of Medicine, Blantyre, Malawi
    Antivir Ther 12:253-60. 2007
    ..To investigate nevirapine concentrations in African HIV-infected children receiving divided Triomune tablets (stavudine+lamivudine+nevirapine)...
  17. ncbi Transient viral load increases in HIV-infected children in the U.K. and Ireland: what do they mean?
    Katherine J Lee
    MRC Clinical Trials Unit, London, UK
    Antivir Ther 12:949-56. 2007
    ..To investigate transient increases in viral load during sustained suppression in children in the UK and Ireland Collaborative HIV Paediatric Study (CHIPS)...
  18. ncbi Nevirapine, stavudine and lamivudine pharmacokinetics in African children on paediatric fixed-dose combination tablets
    Rafaëlla F A L'homme
    Department of Clinical Pharmacy, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    AIDS 22:557-65. 2008
    ..We determined whether this ratio results in optimal exposure in the target population...
  19. ncbi The cost-effectiveness of cotrimoxazole prophylaxis in HIV-infected children in Zambia
    Mairin Ryan
    National Centre for Pharmacoeconomics, Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
    AIDS 22:749-57. 2008
    ....
  20. ncbi Patterns of individual and population-level adherence to antiretroviral therapy and risk factors for poor adherence in the first year of the DART trial in Uganda and Zimbabwe
    Sylvia K Muyingo
    MRC Uganda Research Unit on AIDS, Entebbe, Uganda
    J Acquir Immune Defic Syndr 48:468-75. 2008
    ..Good adherence is essential for successful antiretroviral therapy (ART) provision, but simple measures have rarely been validated in Africa...
  21. ncbi Estimating glomerular filtration rate in HIV-infected adults in Africa: comparison of Cockcroft-Gault and Modification of Diet in Renal Disease formulae
    Wolfgang Stöhr
    MRC Clinical Trials Unit, London, UK
    Antivir Ther 13:761-70. 2008
    ....
  22. ncbi Short-term CD4 cell response after highly active antiretroviral therapy initiated at different times from seroconversion in 1,500 seroconverters
    Abdel Babiker
    MRC Clinical Trials Unit, London, United Kingdom
    J Acquir Immune Defic Syndr 32:303-10. 2003
    ..After that time, there is little to be gained in terms of short-term response from initiating HAART before reaching a CD4 count of 200 cells/microL...
  23. ncbi Prevalence, incidence and predictors of severe anaemia with zidovudine-containing regimens in African adults with HIV infection within the DART trial
    Francis Ssali
    Joint Clinical Research Centre, Kampala, Uganda
    Antivir Ther 11:741-9. 2006
    ..Clinical vigilance and haemoglobin measurements 4, 8 and 12 weeks after starting zidovudine could help to manage serious anaemia...
  24. ncbi A randomized controlled trial of genotypic HIV drug resistance testing in HIV-1-infected children: the PERA (PENTA 8) trial
    Hannah Green
    MRC Clinical Trials Unit, London, UK
    Antivir Ther 11:857-67. 2006
    ..To evaluate the longer-term utility of genotypic resistance testing in HIV-1-infected children with virological failure...
  25. ncbi Do patients who are infected with drug-resistant HIV have a different CD4 cell decline after seroconversion? An exploratory analysis in the UK Register of HIV Seroconverters
    Krishnan Bhaskaran
    Medical Research Council Clinical Trials Unit, London, UK
    AIDS 18:1471-3. 2004
    ..The virological and host determinants of this possible phenomenon are worth further exploration...
  26. ncbi Immunologic changes during unplanned treatment interruptions of highly active antiretroviral therapy in children with human immunodeficiency virus type 1 infection
    Diana M Gibb
    Medical Research Council Trials Unit, London, UK
    Pediatr Infect Dis J 23:446-50. 2004
    ..There are few data on the decline of CD4 cells or percentage during unplanned treatment interruptions in HIV-infected children...
  27. ncbi Drug switching and virologic-based endpoints in trials of antiretroviral drugs for HIV infection
    Andrew N Phillips
    AIDS 18:365-70. 2004
  28. ncbi Systemic non-Hodgkin lymphoma in individuals with known dates of HIV seroconversion: incidence and predictors
    Krishnan Bhaskaran
    MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    AIDS 18:673-81. 2004
    ..CONCLUSION: There appears to be no justification for initiating HAART at CD4 cell counts > 100 x 10 cells/l based specifically on concerns over NHL. The risk of NHL is, however, greatly increased at lower CD4 cell counts...
  29. ncbi Parametric randomization-based methods for correcting for treatment changes in the assessment of the causal effect of treatment
    A Sarah Walker
    MRC Clinical Trials Unit, HIV Division, 222 Euston Road, London NW1 2DA, U K
    Stat Med 23:571-90. 2004
    ..The Concorde trial of immediate versus deferred zidovudine in HIV infection is used as a motivating example and illustration of the methods...
  30. ncbi Determinants of survival following HIV-1 seroconversion after the introduction of HAART
    Kholoud Porter
    Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
    Lancet 362:1267-74. 2003
    ..Highly active antiretroviral therapy (HAART) was introduced in 1997. We aimed to assess the continuing effect of this treatment on survival and progression to AIDS after HIV-1 seroconversion...
  31. ncbi Evolution of antiretroviral phenotypic and genotypic drug resistance in antiretroviral-naive HIV-1-infected children treated with abacavir/lamivudine, zidovudine/lamivudine or abacavir/zidovudine, with or without nelfinavir (the PENTA 5 trial)
    Diana M Gibb
    Medical Research Council Clinical Trials Unit, London, UK
    Antivir Ther 7:293-303. 2002
    ....
  32. ncbi Biphasic decay of cell-associated HIV-1 DNA in HIV-1-infected children on antiretroviral therapy
    Anita De Rossi
    Department of Oncology and Surgical Sciences, AIDS Reference Centre, Padova, Italy
    AIDS 16:1961-3. 2002
  33. ncbi Impact of human immunodeficiency virus type 1 subtypes on virologic response and emergence of drug resistance among children in the Paediatric European Network for Treatment of AIDS (PENTA) 5 trial
    Deenan Pillay
    Public Health Laboratory Service Antiviral Susceptibility Reference Unit, Birmingham Public Health Laboratory, Birmingham, United Kingdom
    J Infect Dis 186:617-25. 2002
    ..No differences were observed in the frequency of development of resistance mutations L90M (P=1.00) and D30N (P=.61) in B and non-B viruses. In conclusion, no evidence that subtype determined virologic response to therapy was found...
  34. ncbi Predictors of trend in CD4-positive T-cell count and mortality among HIV-1-infected individuals with virological failure to all three antiretroviral-drug classes
    Bruno Ledergerber
    Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Ramistrasse 100, CH 8091 Zurich, Switzerland
    Lancet 364:51-62. 2004
    ..We aimed to assess the inter-relations between viral load, CD4-cell count, and clinical outcome in patients who had experienced three-class virological failure...
  35. ncbi HIV/HCV coinfection, HAART, and liver-related mortality
    Caroline A Sabin
    Lancet 364:757-8; author reply 758. 2004
  36. ncbi Effect of cotrimoxazole on causes of death, hospital admissions and antibiotic use in HIV-infected children
    Veronica Mulenga
    University Teaching Hospital, Lusaka, Zambia
    AIDS 21:77-84. 2007
    ..Cotrimoxazole prophylaxis reduces morbidity and mortality in HIV-1-infected children, but mechanisms for these benefits are unclear...
  37. ncbi Determinants of survival without antiretroviral therapy after infancy in HIV-1-infected Zambian children in the CHAP Trial
    A Sarah Walker
    MRC Clinical Trials Unit, London, UK
    J Acquir Immune Defic Syndr 42:637-45. 2006
    ..There are few data on predictors of HIV progression in untreated children in resource-limited settings...
  38. ncbi Adherence and acceptability of once daily Lamivudine and abacavir in human immunodeficiency virus type-1 infected children
    Marthe LePrevost
    Family Clinic, North West London NHS Trust, London, United Kingdom
    Pediatr Infect Dis J 25:533-7. 2006
    ..CONCLUSION: Adherence to once daily abacavir/lamivudine was good with no evidence of an association between nonadherence and virologic rebound. Acceptability of once daily drugs was best when the whole regimen was dosed once daily...
  39. ncbi Underdosing of antiretrovirals in UK and Irish children with HIV as an example of problems in prescribing medicines to children, 1997-2005: cohort study
    Esse N Menson
    MRC Clinical Trials Unit, London NW1 2DA
    BMJ 332:1183-7. 2006
    ..CONCLUSIONS: Largely inadvertently, HIV infected children in the United Kingdom and Ireland have been underdosed with antiretrovirals, highlighting problems applicable throughout paediatric prescribing...
  40. ncbi Outcomes for human immunodeficiency virus-1-infected infants in the United kingdom and Republic of Ireland in the era of effective antiretroviral therapy
    Katja Doerholt
    St. Peter's Hospital, Chertsey
    Pediatr Infect Dis J 25:420-6. 2006
    ..Poor virologic response to ART during infancy is of concern because of increased likelihood of early development of resistance...
  41. ncbi Relationship between changes in thymic emigrants and cell-associated HIV-1 DNA in HIV-1-infected children initiating antiretroviral therapy
    Anita De Rossi
    Department of Oncology and Surgical Sciences, AIDS Reference Centre, Padova, Italy
    Antivir Ther 10:63-71. 2005
    ....
  42. ncbi Response to highly active antiretroviral therapy varies with age: the UK and Ireland Collaborative HIV Paediatric Study
    A Sarah Walker
    AIDS 18:1915-24. 2004
    ..Differences in response to HAART according to age and underlying risk of disease progression should be considered when initiating HAART in children...
  43. ncbi Increased thymic output after initiation of antiretroviral therapy in human immunodeficiency virus type 1-infected children in the Paediatric European Network for Treatment of AIDS (PENTA) 5 Trial
    Anita De Rossi
    Department of Oncology and Surgical Sciences, AIDS Reference Center, Padova, Italy
    J Infect Dis 186:312-20. 2002
    ..Thymic output appears to be the main source of CD4 cell repopulation in children receiving ART. Recovery of thymic function is independent of age and influenced by the status of peripheral CD4 cell depletion and HIV-1 suppression...
  44. ncbi Clinical trials in children
    Esse N Menson
    Lancet 364:2176-7. 2004
  45. ncbi Severe renal dysfunction and risk factors associated with renal impairment in HIV-infected adults in Africa initiating antiretroviral therapy
    Andrew Reid
    University of Zimbabwe, Harare, Zimbabwe
    Clin Infect Dis 46:1271-81. 2008
    ..We sought to investigate renal function in previously untreated symptomatic human immunodeficiency virus (HIV)-infected adults with CD4(+) cell counts of <200 cells/mm(3) who were undergoing antiretroviral therapy (ART) in Africa...