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Dr Gareth Ambler


Position Senior Lecturer in Medical Statistics
Phone (external) +44(0)20 7679 1878
Phone (internal) 41878
Email(*) g.ambler
Themes Biostatistics

* @ucl.ac.uk

Biographical Details

Gareth Ambler

Gareth is a senior lecturer in Medical Statistics at the Department of Statistical Science, UCL and a member of the Biostatistics Group within the Research Support Centre. Gareth completed a PhD in Statistics in 1996 at the University of Sussex. This considered changes of in-hospital mortality following myocardial infarction over an eight year period. Previously he worked in the department of Medical Statistics at Imperial College School of Medicine. 


Research Interests

  • The formulation and validation of risk prediction models
  • Methods to handle missing data
  • Hierarchical models
  • Clinical trials

Current Research Students


Selected Recent Grants

  • Health-Related Quality of Life in two treatment pathways for primary open angle glaucoma and ocular hypertension: a randomised controlled trial of initial selective laser trabeculoplasty versus conventional medical therapy (PI: Dr Gus Gazzard, Institute of Ophthalmology), NIHR HTA, start 1/1/12 (72 months).
  • EACH study: Evaluation of Array Comparative genomic Hybridisation in prenatal diagnosis of fetal anomalies (PI: Dr Steve Robson, Newcastle University), NIHR EME, start 1/10/11 (36 months).
  • Optimising team functioning, preventing relapse and enhancing recovery in crisis resolution teams: the CORE programme (CRT Optimisation and RElapse prevention) (PI: Dr Sonia Johnson, UCL), NIHR Programme Grant, start 1/10/11 (60 months).
  • The effect of neo-adjuvant chemotherapy on exercise capacity and outcome following upper gastrointestinal cancer surgery (PI: Dr Mike Grocott, UCL), NIHR RfPB, start 1/12/10 (36 months).

Selected publications

    2014

    • Jack, S., West, M. A., Raw, D., Marwood, S., Ambler, G., Cope, T. M., Shrotri, M., Sturgess, R. P., Calverley, P. M. A., Ottensmeier, C. H., Grocott, M. P. W. (2014). The effect of neoadjuvant chemotherapy on physical fitness and survival in patients undergoing oesophagogastric cancer surgery. EJSO 40(10), 1313-1320 doi:10.1016/j.ejso.2014.03.010. Author URL
    • Moore, C. M., Robertson, N., Jichi, F., Ambler, G., Freeman, A., Jameson, C., Whitcher, B., Gambarota, G., Allen, C., Kirkham, A., Emberton, M. (2014). MAPPED: Magnetic resonance imaging in Primary Prostate cancer after Exposure to Dutasteride: Reduction in tumour volume at 6 months in men on active surveillance for prostate cancer. BJU INTERNATIONAL. ( Vol. 113 pp.12-12). Author URL
    • Riazi, A., Walters, K., Rubin, G., Ambler, G., Jichi, F., Mynors-Wallis, L., O'Driscoll, M., Stephen, J., Aspden, T. (2014). A pilot randomised controlled trial of Problem-Solving Treatment for Visual Impairment (POSITIVE): Protocol paper. Ophthalmic Physiol Opt 34(4), 489-497 doi:10.1111/opo.12135. Author URL

    2013

    • Hassiotis, A., Ali, A., Ambler, G., Strydom, A., Mcmanus, S., Meltzer, H., Cooper, C. (2013). Interplay between intelligence level and happiness: The contribution of socioeconomic and clinical factors. JOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES 10(2), 126-126 Author URL
    • Nunes, N., Ambler, G., Hoo, W. L., Naftalin, J., Foo, X., Widschwendter, M., Jurkovic, D. (2013). PROSPECTIVE VALIDATION OF THE IOTA LOGISTIC REGRESSION MODELS (LR1/LR2) BY A LEVEL-2 ULTRASOUND OPERATOR AND COMPARISON TO PATTERN RECOGNITION FOR THE DIAGNOSIS OF OVARIAN CANCER. INTERNATIONAL JOURNAL OF GYNECOLOGICAL CANCER 23(8) Author URL
    • Robertson, N. L., Moore, C. M., Ambler, G., Bott, S. R., Freeman, A., Gambarota, G., Jameson, C., Mitra, A. V., Whitcher, B., Winkler, M., Kirkham, A., Allen, C., Emberton, M. (2013). MAPPED study design: A 6 month randomised controlled study to evaluate the effect of dutasteride on prostate cancer volume using magnetic resonance imaging. Contemp Clin Trials 34(1), 80-89 doi:10.1016/j.cct.2012.10.003. Author URL
    • Smith, L., Ucci, M., Marmot, A., Spinney, R., Laskowski, M., Sawyer, A., Konstantatou, M., Hamer, M., Ambler, G., Wardle, J., Fisher, A. (2013). Active buildings: Modelling physical activity and movement in office buildings. An observational study protocol. BMJ Open 3(11), e004103- doi:10.1136/bmjopen-2013-004103.

    2012

    • Ali, A., Ambler, G., Strydom, A., Rai, D., Cooper, C., McManus, S., Weich, S., Meltzer, H., Dein, S., Hassiotis, A. (2012). The relationship between happiness and intelligent quotient: the contribution of socio-economic and clinical factors. Psychological Medicine
    • AMBLER, G., Seaman, S., Omar, R. Z. (2012). An evaluation of penalised survival methods for developing prognostic models with rare events. Statistics in Medicine 31(11-12), 1150-1161 doi:10.1002/sim.4371. Publisher URL
    • Nunes, N., Yazbek, J., Ambler, G., Hoo, W., Naftalin, J., Jurkovic, D. (2012). Prospective evaluation of the IOTA logistic regression model LR2 for the diagnosis of ovarian cancer. Ultrasound in Obstetrics & Gynecology 40, 355-359 doi:10.1002/uog.11088.

    2011

    • Matthews, E., Miller, J. A., MacLeod, M. R., Ironside, J., Ambler, G., Labrum, R., Sud, R., Holton, J. L., Hanna, M. G. (2011). SODIUM AND CHLORIDE CHANNELOPATHIES WITH MYOSITIS: COINCIDENCE OR CONNECTION? Muscle Nerve 44(2), 283-288 doi:10.1002/mus.22120. Author URL

    2010

    • Godden, S., Ambler, G., Pollock, A. M. (2010). 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 trust in England. J MED ETHICS 36(6), 358-362 doi:10.1136/jme.2009.033845.
    • Goebel, A., Baranowski, A., Ghiai, A., Maurer, K., McCabe, C., Ambler, G. (2010). Skepticism About Intravenous Immunoglobulin Treatment in Long-Standing Complex Regional Pain Syndrome. ANN INTERN MED 152(12), 829-830
    • Goebel, A., Baranowski, A., Maurer, K., Ghiai, A., McCabe, C., Ambler, G. (2010). Intravenous Immunoglobulin Treatment of the Complex Regional Pain Syndrome A Randomized Trial. ANN INTERN MED 152(3), 152-U7
    • Kamal, N., AMBLER, G., Omar, R. Z. (2010). Post MFA effects on women’s jobs in Bangladesh. Independent Business Review 3(2)
    • Raine, R., Scholes, S., Wong, W., Ashton, C., Obichere, A., Ambler, G. (2010). 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. BMJ (Clinical Research Ed.) 340, b5479 [Submitted]

    2009

    • Berkovitz, S., Ambler, G., Jenkins, M., Thurgood, S. (2009). Serum 25-hydroxy Vitamin D Levels in Chronic Fatigue Syndrome: a Retrospective Survey. INT J VITAM NUTR RES 79(4), 250-254 doi:10.1024/0300-9831.79.4.250.
    • Kayes, O. J., Loddo, M., Patel, N., Patel, P., Minhas, S., Ambler, G., Freeman, A., Wollenschlaeger, A., Ralph, D. J., Stoeber, K., Williams, G. H. (2009). DNA Replication Licensing Factors and Aneuploidy Are Linked to Tumor Cell Cycle State and Clinical Outcome in Penile Carcinoma. Clin Cancer Res 15(23), 7335-7344 doi:10.1158/1078-0432.CCR-09-0882. Author URL
    • Kayes, O., Loddo, M., AMBLER, G., Stoeber, K., Williams, G. H., Ralph, D. J., Minhas, S. (2009). DNA Replication Licensing Factors And Aneuploidy Are Linked To Tumour Cell Cycle States And Clinical Outcome In Penile Carcinoma. European Urology Supplements. ( Vol. 8 pp.368-368).
    • Raine, R., Wong, W., Ambler, G., Petersen, I., Hardoon, S., Morris, R. (2009). Sociodemographic variations in the contribution of secondary drug prevention to stroke survival at middle and older ages: cohort study. BMJ (Clinical Research Ed.) 338, b1279- doi:10.1136/bmj.b1279. Author URL

    2007

    • Ambler, G., Omar, R. Z., Royston, P. (2007). A comparison of imputation techniques for handling missing predictor values in a risk model with a binary outcome. Statistical Methods in Medical Research 16(3), 277-298 doi:10.1177/0962280206074466.
    • Barber, J., Ambler, G., Omar, R. Z. (2007). Analysis of Health Studies. In Shergill, I. S., Ayra, M., Patel, H. (Eds.). Basic Science Techniques in Clinical Practice ( ). London Springer-Verlag.
    • Omar, R. Z., Barber, J., Ambler, G. (2007). Design of Health Studies. In Shergill, I. S., Ayra, M., Patel, H. (Eds.). Basic Science Techniques in Clinical Practice ( ). London Springer-Verlag.

    2006

    • Bessant, R., Duncan, R., Ambler, G., Swanton, J., Isenberg, D. A., Gordon, C., Rahman, A. (2006). Prevalence of conventional and lupus-specific risk factors for cardiovascular disease in patients with systemic lupus erythematosus: A case-control study. Arthritis Care and Research 55(6), 892-899 doi:10.1002/art.22343.
    • Omar, R. Z., McNally, N., Ambler, G., Pollock, A. M. (2006). Quality research in healthcare: are researchers getting enough statistical support? BMC HEALTH SERV RES 6, 2 doi:10.1186/1472-6963-6-2.

    2005

    • Ambler, G., Omar, R., Royston, P., Kinsman, R., Keogh, B., Taylor, K. (2005). Generic, simple risk stratification model for heart valve surgery. Circulation 112, 224-231 doi:10.1161/CIRCULATIONAHA.104.515049.
    • O'Sullivan, C., Omar, R. Z., Ambler, G., Majeed, A. (2005). Case-mix and variation in specialist referrals in general practice. British Journal of General Practice 55(516), 529-533
    • Omar, R. Z., Ambler, G., Royston, P., Taylor, K. M. (2005). Impact of missing predictor values on risk stratification models in cardiac surgery. CIRCULATION. ( Vol. 111 pp.E337-E337). LIPPINCOTT WILLIAMS & WILKINS.

    2004

    • Harper, C. M., Ambler, G., Edge, G. (2004). The prognostic value of pre-operative predicted forced vital capacity in corrective spinal surgery for Duchenne's muscular dystrophy. ANAESTHESIA 59(12), 1160-1162
    • Omar, R. Z., Ambler, G., Eliahoo, J., Royston, P., Taylor, K. M. (2004). Cardiac surgery risk modeling for mortality: a review of current practice and suggestions for improvement. The Annals of Thoracic Surgery 77, 2232-2237 doi:10.1016/j.athoracsur.2003.10.032.
    • Rahman, A., Ambler, G., Underwood, M., Shipley, M. E. (2004). Important determinants of self-efficacy in patients with chronic musculoskeletal pain. Journal of Rheumatology 31, 1187-1192 Author URL
    • Saxena, S., Ambler, G., Cole, T. J., Majeed, A. (2004). Ethnic group differences in overweight and obese children and young people in England: cross sectional survey. Archives of Disease in Childhood 89(1), 30-36
    • Stephens, J. W., Ambler, G., Vallance, P., Betteridge, D. J., Humphries, S. E., Hurel, S. J. (2004). Cardiovascular risk and diabetes. Are the methods of risk prediction satisfactory? Eur J Cardiovasc Prev Rehabil 11(6), 521-528 Author URL

    2003

    • Al Ruzzeh, S., Ambler, G., Asimakopoulos, G., Omar, R. Z., Hassan, R., Fabri, B., El Gamel, A., DeSouza, T., Zamvar, V., Keenan, D. (2003). Off-pump coronary artery bypass surgery reduces risk-stratified morbidity and mortality: a UK multi-center comparative analysis of early clinical outcome. Circulation 108 Su, 1-8
    • Al Ruzzeh, S., Asimakopoulos, G., Ambler, G., Omar, R. Z., Hasan, R., Fabri, B., El Gamel, A., DeSouza, T., Zamvar, V., Griffin, S. (2003). Validation of four different risk stratification systems in patients undergoing off-pump coronary bypass graft surgery. Heart 89, 432-435
    • Al-Ruzzeh, S., Asimakopoulos, G., Ambler, G., Omar, R., Hasan, R., Fabri, B., El-Gamel, A., DeSouza, A., Zamvar, V., Griffin, S., Keenan, D., Trivedi, U., Pullan, M., Cale, A., Cowen, M., Taylor, K., Amrani, M. (2003). Validation of four different risk stratification systems in patients undergoing off-pump coronary artery bypass surgery: a UK multicentre analysis of 2223 patients. HEART. ( Vol. 89 pp.432-435). BRITISH MED JOURNAL PUBL GROUP.
    • Ambler, G., Omar, R. Z., Royston, P., Taylor, K. M. (2003). A risk score for predicting short-term mortality following heart valve surgery. CIRCULATION. ( Vol. 108 pp.755-756). LIPPINCOTT WILLIAMS & WILKINS.
    • Ambler, G., Omar, R., Royston, P., Taylor, K. (2003). A prognostic model for heart valve surgery. CONTROLLED CLINICAL TRIALS. ( Vol. 24 pp.231S-231S). ELSEVIER SCIENCE INC.
    • Ambler, G., Royston, P., Head, J. (2003). Non-linear models for the relation between cardiovascular risk factors and intake of wine, beer and spirits. Statistics in Medicine 22(3), 363-383 doi:10.1002/sim.1359.
    • Asimakopoulos, G., Al Ruzzeh, S., Ambler, G., Omar, R. Z., Punjabi, B., Amrani, M., Taylor, K. M. (2003). An evaluation of existing risk stratification models as a tool for comparison of surgical performances for CABG between institutions. European Journal of Cardio-Thoracic Surgery 23, 935-942
    • Majeed, A., Gray, J., Ambler, G., Carroll, K., Bindman, A. B. (2003). Association between practice size, volume of cases, and quality of care of patients with ischaemic heart disease in primary care: Cross-sectional study. BMJ (Clinical Research Ed.) 326, 371-372
    • Omar, R. Z., Ambler, G., Taylor, K. M. (2003). Assessment of quality of care in cardiac surgery: An overview of risk models. In Mohan, R. (Ed.). Recent Advances in Cardiology 2: Global Research Network ( pp.13-20). India
    • Omar, R., Ambler, G., Royston, P., Eliahoo, J., Taylor, K. (2003). Risk models in cardiac surgery - A comprehensive review of methods. CONTROLLED CLINICAL TRIALS. ( Vol. 24 pp.184S-185S). ELSEVIER SCIENCE INC.
    • Stephens, J. W., Ambler, G., Betteridge, D. J. (2003). Cardiovascular risk prediction in diabetes: a ten year retrospective study to examine methods of risk analysis. Diabetic Medicine. ( Vol. 20 pp.21-).

    2002

    • Al-Ruzzeh, S. M., Asimakopoulos, G., Ambler, G., Omar, R., Hasan, R., Fabri, B., El-Gamel, A., DeSouza, T., Zamvar, V., Griffin, S., Keenan, D., Triveil, U., Pullan, M., Cale, A., Cowen, M., Taylor, K., Amrani, M. (2002). Off-pump coronary artery bypass (OPCAB) surgery reduces morbidity and risk-stratified mortality. Local and national comparisons: Initial UK multi-centre analysis of early clinical outcome. CIRCULATION. ( Vol. 106 pp.377-377). LIPPINCOTT WILLIAMS & WILKINS.
    • Ambler, G., Brady, A. R., Royston, P. (2002). Simplifying a prognostic model: A simulation study based on clinical data. Statistics in Medicine 21(24), 3803-3822 doi:10.1002/sim.1422.

    2001

    • Ambler, G., Royston, P. (2001). Fractional polynomial model selection procedures: Investigation of type I error rate. Journal of Statistical Computation and Simulation 69, 89-108 doi:10.1080/00949650108812083.

    1999

    • Royston, P., AMBLER, G. (1999). Multivariable fractional polynomials: update. Stata Technical Bulletin 49, 17-23
    • Royston, P., AMBLER, G. (1999). Nonlinear regression models involving power or exponential functions of covariates. Stata Technical Bulletin 49, 25-30
    • Royston, P., AMBLER, G., Sauerbrei, W. (1999). The use of fractional polynomials to model continuous risk variables in epidemiology, International Journal of Epidemiology. International Journal of Epidemiology 28, 964-974

    1998

    • Royston, P., AMBLER, G. (1998). Generalized additive models. Stata Technical Bulletin 42, 38-43
    • Royston, P., AMBLER, G. (1998). Multivariable fractional polynomials. Stata Technical Bulletin 43, 24-32

    1997

    • AMBLER, G., Royston, P. (1997). Good statistical practice. In Minder, C. E., Friedl, H. (Eds.). Good statistical practice: Proceedings of the 12th International Workshop on Statistical Modelling ( pp.90-94).

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