Gareth Ambler

Summary

Affiliation: University College London
Country: UK

Publications

  1. doi request reprint An evaluation of penalised survival methods for developing prognostic models with rare events
    G Ambler
    Department of Statistical Science, University College London, London, UK
    Stat Med 31:1150-61. 2012
  2. ncbi request reprint A comparison of imputation techniques for handling missing predictor values in a risk model with a binary outcome
    Gareth Ambler
    Department of Statistical Science, University College London Joint UCLH UCL Biomedical Research Unit, London, UK
    Stat Methods Med Res 16:277-98. 2007
  3. ncbi request reprint Simplifying a prognostic model: a simulation study based on clinical data
    Gareth Ambler
    Department of Statistical Science, University College, 1 19 Torrington Place, London WC1E 7HB, UK
    Stat Med 21:3803-22. 2002
  4. ncbi request reprint Non-linear models for the relation between cardiovascular risk factors and intake of wine, beer and spirits
    Gareth Ambler
    Department of Statistical Science, University College London, 1 19 Torrington Place, London WC1E 6BT, UK
    Stat Med 22:363-83. 2003
  5. ncbi request reprint Generic, simple risk stratification model for heart valve surgery
    Gareth Ambler
    Department of Statistical Science, University College, London, UK
    Circulation 112:224-31. 2005
  6. pmc Quality research in healthcare: are researchers getting enough statistical support?
    Rumana Z Omar
    Research and Development, University College London Hospitals NHS Foundation Trust, Maple House, London W1P 9LL, UK
    BMC Health Serv Res 6:2. 2006
  7. ncbi request reprint Important determinants of self-efficacy in patients with chronic musculoskeletal pain
    Anisur Rahman
    Centre for Rheumatology, University College London, London, UK
    J Rheumatol 31:1187-92. 2004
  8. doi request reprint Recruitment of minority ethnic groups into clinical cancer research trials to assess adherence to the principles of the Department of Health Research Governance Framework: national sources of data and general issues arising from a study in one hospital tr
    Sylvia Godden
    Department of Epidemiology and Public Health, Health Care Evaluation Group, UCL, London, England
    J Med Ethics 36:358-62. 2010
  9. pmc Sociodemographic variations in the contribution of secondary drug prevention to stroke survival at middle and older ages: cohort study
    Rosalind Raine
    Department of Epidemiology and Public Health, University College London, London WC1E 6BT
    BMJ 338:b1279. 2009
  10. pmc Association between practice size and quality of care of patients with ischaemic heart disease: cross sectional study
    Azeem Majeed
    Primary Care Research Unit, School of Public Policy, University College London, London WC1H 9QU
    BMJ 326:371-2. 2003

Collaborators

Detail Information

Publications18

  1. doi request reprint An evaluation of penalised survival methods for developing prognostic models with rare events
    G Ambler
    Department of Statistical Science, University College London, London, UK
    Stat Med 31:1150-61. 2012
    ..The ridge method generally performed the best, although lasso is recommended if variable selection is required...
  2. ncbi request reprint A comparison of imputation techniques for handling missing predictor values in a risk model with a binary outcome
    Gareth Ambler
    Department of Statistical Science, University College London Joint UCLH UCL Biomedical Research Unit, London, UK
    Stat Methods Med Res 16:277-98. 2007
    ..MICE was amongst the best performing multiple imputation methods with regards to the quality of the predictions. Additionally, it produced the least biased estimates, with good coverage, and hence is recommended for use in practice...
  3. ncbi request reprint Simplifying a prognostic model: a simulation study based on clinical data
    Gareth Ambler
    Department of Statistical Science, University College, 1 19 Torrington Place, London WC1E 7HB, UK
    Stat Med 21:3803-22. 2002
    ..Optimizing the Akaike information criterion appears to be appropriate for choosing the degree of simplification...
  4. ncbi request reprint Non-linear models for the relation between cardiovascular risk factors and intake of wine, beer and spirits
    Gareth Ambler
    Department of Statistical Science, University College London, 1 19 Torrington Place, London WC1E 6BT, UK
    Stat Med 22:363-83. 2003
    ..However, having clarified these issues, the apparent benefit of consuming wine instead of other alcoholic beverages may be relatively small...
  5. ncbi request reprint Generic, simple risk stratification model for heart valve surgery
    Gareth Ambler
    Department of Statistical Science, University College, London, UK
    Circulation 112:224-31. 2005
    ..This study aims to develop a simple risk model to predict the risk of in-hospital mortality for patients undergoing heart valve surgery to provide information to patients and clinicians and to facilitate institutional comparisons...
  6. pmc Quality research in healthcare: are researchers getting enough statistical support?
    Rumana Z Omar
    Research and Development, University College London Hospitals NHS Foundation Trust, Maple House, London W1P 9LL, UK
    BMC Health Serv Res 6:2. 2006
    ..This issue was highlighted several years ago and it was suggested that more investments were needed from health care organisations and Universities to alleviate this problem...
  7. ncbi request reprint Important determinants of self-efficacy in patients with chronic musculoskeletal pain
    Anisur Rahman
    Centre for Rheumatology, University College London, London, UK
    J Rheumatol 31:1187-92. 2004
    ..To define the presenting characteristics of a population of patients with chronic musculoskeletal pain seen in a tertiary rheumatology clinic, and to investigate which factors are associated with self-efficacy in these patients...
  8. doi request reprint Recruitment of minority ethnic groups into clinical cancer research trials to assess adherence to the principles of the Department of Health Research Governance Framework: national sources of data and general issues arising from a study in one hospital tr
    Sylvia Godden
    Department of Epidemiology and Public Health, Health Care Evaluation Group, UCL, London, England
    J Med Ethics 36:358-62. 2010
    ....
  9. pmc Sociodemographic variations in the contribution of secondary drug prevention to stroke survival at middle and older ages: cohort study
    Rosalind Raine
    Department of Epidemiology and Public Health, University College London, London WC1E 6BT
    BMJ 338:b1279. 2009
    ....
  10. pmc Association between practice size and quality of care of patients with ischaemic heart disease: cross sectional study
    Azeem Majeed
    Primary Care Research Unit, School of Public Policy, University College London, London WC1H 9QU
    BMJ 326:371-2. 2003
  11. ncbi request reprint Cardiovascular risk and diabetes. Are the methods of risk prediction satisfactory?
    Jeffrey W Stephens
    Department of Diabetes and Endocrinology, UCL Hospitals, Mortimer Street, London, UK
    Eur J Cardiovasc Prev Rehabil 11:521-8. 2004
    ..Our aim was to examine their efficacy in a clinic-based population of diabetic patients...
  12. pmc DNA replication licensing factors and aneuploidy are linked to tumor cell cycle state and clinical outcome in penile carcinoma
    Oliver J Kayes
    Department of Pathology, University College London, London, United Kingdom
    Clin Cancer Res 15:7335-44. 2009
    ..We have analyzed replication licensing factors (RLF), together with DNA ploidy status, to investigate their role in progression of penile squamous cell carcinoma and to assess their utility as novel prognostic tools...
  13. pmc Social variations in access to hospital care for patients with colorectal, breast, and lung cancer between 1999 and 2006: retrospective analysis of hospital episode statistics
    Rosalind Raine
    Department of Epidemiology and Public Health, University College London, London WC1E 6BT
    BMJ 340:b5479. 2010
    ..To determine the extent to which type of hospital admission (emergency compared with elective) and surgical procedure varied by socioeconomic circumstances, age, sex, and year of admission for colorectal, breast, and lung cancer...
  14. doi request reprint Serum 25-hydroxy vitamin D levels in chronic fatigue syndrome: a retrospective survey
    Saul Berkovitz
    Royal London Homeopathic Hospital, University College London Hospitals NHS Trust, London, UK
    Int J Vitam Nutr Res 79:250-4. 2009
    ..We hypothesized that serum 25-OH vitamin D levels are lower in CFS patients than in the general British population...
  15. ncbi request reprint Prevalence of conventional and lupus-specific risk factors for cardiovascular disease in patients with systemic lupus erythematosus: A case-control study
    Rupa Bessant
    University College London, London, UK
    Arthritis Rheum 55:892-9. 2006
    ..We compared the prevalence of conventional and lupus-specific risk factors in patients with SLE just before a cardiovascular event and in matched controls with SLE but no cardiovascular disease (CVD)...
  16. pmc Case-mix and variation in specialist referrals in general practice
    Caoimhe O Sullivan
    University College London Hospital NHS Trust
    Br J Gen Pract 55:529-33. 2005
    ..The potential of a comprehensive measure of patient morbidity to explain variation in referrals to secondary care has not previously been examined in the UK...
  17. ncbi request reprint Cardiac surgery risk modeling for mortality: a review of current practice and suggestions for improvement
    Rumana Z Omar
    MRC Clinical Trials Unit London, London, United Kingdom
    Ann Thorac Surg 77:2232-7. 2004
    ..Model development and validation processes are not always linked to the clinical aim of the model, which may affect their clinical validity. We make some suggestions in this review for improvement in methodology and reporting...
  18. ncbi request reprint Off-Pump Coronary Artery Bypass (OPCAB) surgery reduces risk-stratified morbidity and mortality: a United Kingdom Multi-Center Comparative Analysis of Early Clinical Outcome
    Sharif Al-Ruzzeh
    National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Harefield Hospital, Middlesex UB9 6JH, United Kingdom
    Circulation 108:II1-8. 2003
    ....