University of Exeter Medical School

Dr Tristan Snowsill

Dr Tristan Snowsill

Senior Lecturer in Health Economics

 T.M.Snowsill@exeter.ac.uk

 6092

 +44 (0) 1392 726092

 South Cloisters 1.11

 

South Cloisters, University of Exeter, St Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK

Overview

I joined the Health Economics Group in October 2017, after six years working in the health technology assessment group, PenTAG, also in the University of Exeter Medical School.

I have significant experience in model-based economic evaluations of health technologies (e.g., drugs, devices, care pathways), particularly of diagnostic and screening tests. These decision models can be used to inform policy decisions around whether particular technologies would represent good value for the NHS. Building these models generally requires reviews of clinical and economic literature, evidence synthesis and other forms of statistical modelling.

In this role I am also contributing to economic evaluations alongside trials. Economic evaluations are key components of trials developed by and with the medical school to put them in a policy context, and to increase the likelihood of the trials impacting policy and practice. I will particularly be working on trials of physical activity for smoking reduction and maintaining mobility in retired older people.

My methodological interests include:

  • Improving the efficiency and flexibility of model-based economic evaluations
  • Evidence synthesis through maximum likelihood and Bayesian methods

I also have a specific interest in interventions to identify and manage Lynch syndrome, a hereditary cancer syndrome which is responsible for around 3% of bowel and uterine cancer.

I am also the founder and former chair of the Institute of Health Research Early Career Researcher Network (ECRN). We meet regularly to discuss matters affecting early career researchers, to support each other in development and to ensure representation of ECR issues within the college and the University as a whole.

Outside of work my hobbies include music and web/software development. I also regularly listen to podcasts, being a loyal listener to a number of podcasts on topics including politics (UK and US), economics, statistics, Star Wars, science, programming and more.

Qualifications

  • 2008 MEng (Bristol) - 1st class Hons
  • 2012 PhD (Bristol)

Links

Research group links

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Research

Research interests

  • Model-based economic evaluation of health technologies
  • Economic evaluation alongside trials
  • Improving the efficiency and flexibility of model-based economic evaluations
  • Evidence synthesis through maximum likelihood and Bayesian methods

Research projects

Current projects

  • Physical activity for smoking reduction
  • Physical activity for maintaining mobility in retired older people
  • Molecular testing for Lynch syndrome in endometrial cancer patients

Notable previous projects

  • Immunosuppressive agents for kidney transplantation
  • Low-dose CT screening for lung cancer in high-risk asymptomatic individuals
  • Molecular testing for Lynch syndrome in colorectal cancer patients

Research grants

  • 2019 NIHR Health Technology Assessment programme
    Effectiveness and cost-effectiveness of gynaecological surveillance for women with Lynch syndrome: systematic reviews and economic evaluation

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Publications

Journal articles

Taylor AH, Thompson TP, Ussher M, Aveyard P, Murray RL, Harris T, Creanor E, Green C, Streeter A, Chynoweth J, et al (In Press). A randomised controlled trial of tailored support to increase physical activity and reduce smoking in smokers not immediately ready to quit: Protocol for the Trial of physical Activity assisted Reduction of Smoking (TARS) study. BMJ Open
Snowsill T, Stathi A, Green C, Withall J, Greaves CJ, Thompson JL, Taylor G, Gray S, Johansen-Berg H, Bilzon JLJ, et al (In Press). Cost-effectiveness of a community-based physical activity and behaviour maintenance intervention for preventing decline in physical functioning in older people: an economic evaluation of the REACT (Retirement in Action) intervention. The Lancet Public Health
Stathi A, Greaves C, Thompson JL, Withall J, Ladlow P, Taylor G, Medina-Lara A, Snowsill T, Gray S, Green C, et al (In Press). Effect of a physical activity and behaviour maintenance programme on functional mobility decline in older adults: the REACT (REtirement in ACTion) randomised controlled trial. The Lancet Public Health
Creanor S, Green C, Price L, Snowsill T, Creanor E (In Press). Effectiveness and cost-effectiveness of behavioural support for prolonged abstinence for smokers wishing to reduce but not quit: Randomised controlled Trial of physical Activity assisted Reduction of Smoking (TARS). Addiction
Snowsill T, Coelho H, Morrish N, Briscoe S, Boddy K, Smith T, Crosbie EJ, Ryan NAJ, Lalloo F, Hulme CT, et al (In Press). Effectiveness and cost-effectiveness of gynaecological cancer surveillance in Lynch syndrome: Systematic reviews and economic evaluation. Health Technology Assessment
Cooper C, Snowsill T, Worsley C, Prowse A, O'Mara-Eves A, Greenwood H, Noble-Longster J, Boulton E, Strickson A (In Press). Handsearching had best recall but poor efficiency when exporting to a bibliographic tool: case study. Journal of Clinical Epidemiology
Paulden M, Sampson C, O'Mahony JF, Spackman E, McCabe C, Round J, Snowsill T (In Press). Logical Inconsistencies in the Health Years in Total and Equal Value of Life Years Gained. Value in Health
Caswell R, Snowsill T, Houghton J, Chakera A, Shepherd M, Laver T, Knight BA, Hattersley AT, Ellard S (In Press). Non-invasive fetal genotyping by droplet digital PCR to identify maternally-inherited monogenic diabetes variants. Clinical Chemistry
Shaw J, Scotchman E, Paternoster B, Ramos M, Nesbitt S, Sheppard S, Snowsill T, Chitty LS, Chandler N (In Press). Non-invasive fetal genotyping for maternal alleles with droplet digital PCR. Prenatal Diagnosis
Morrish N, Snowsill T, Dodman S, Medina-Lara A (In Press). Preferences for genetic testing to predict risk of developing hereditary cancer: a systematic review of discrete choice experiments. Medical Decision Making
Crosbie EJ, Ryan NAJ, Arends MJ, Bosse T, Burn J, Cornes JM, Crawford R, Eccles D, Frayling IM, Ghaem-Maghami S, et al (In Press). The Manchester International Consensus Group Recommendations for the Management of Gynecological Cancers in Lynch Syndrome. Genetics in Medicine
Ryan NAJ, McMahon R, Tobi S, Snowsill T, Esquibel S, Wallace AJ, Bunstone S, Bowers N, Mosneag IE, Kitson SJ, et al (In Press). The Proportion of Endometrial Tumours Associated with Lynch Syndrome (PETALS): a prospective cross-sectional study. PLoS Medicine
Atwal A, Snowsill T, Cabrera Dandy M, Krum T, Newton C, Evans DG, Crosbie E, Ryan N (In Press). The prevalence of mismatch repair deficiency in ovarian cancer: a systematic review and meta-analysis. International Journal of Cancer
Duer E, Yang H, Robinson S, Grigore B, Sandercock J, Snowsill T, Griffin E, Peters J, Hyde C (2023). Do we know enough about the effect of low-dose computed tomography screening for lung cancer on mortality to act? an updated systematic review, meta-analysis and network meta-analysis of randomised controlled trials 2017 to 2021. Diagn Progn Res, 7(1). Abstract.  Author URL.
Snowsill T (2023). Modelling the Cost-Effectiveness of Diagnostic Tests. PharmacoEconomics, 41(4), 339-351.
Taylor AH, Thompson TP, Streeter A, Chynoweth J, Snowsill T, Ingram W, Ussher M, Aveyard P, Murray RL, Harris T, et al (2023). Motivational support intervention to reduce smoking and increase physical activity in smokers not ready to quit: the TARS RCT. Health Technol Assess, 27(4), 1-277. Abstract.  Author URL.
Shaw J, Scotchman E, Paternoster B, Ramos M, Nesbitt S, Sheppard S, Snowsill T, Chitty LS, Chandler N (2023). Non-invasive fetal genotyping for maternal alleles with droplet digital PCR: a comparative study of analytical approaches. Prenat Diagn, 43(4), 477-488. Abstract.  Author URL.
Stathi A, Withall J, Greaves CJ, Thompson JL, Taylor G, Medina-Lara A, Green C, Snowsill T, Johansen-Berg H, Bilzon J, et al (2022). A group-based exercise and behavioural maintenance intervention for adults over 65 years with mobility limitations: the REACT RCT. Public Health Research, 10(14), 1-172. Abstract.
Snowsill TM, Stathi A, Green C, Withall J, Greaves CJ, Thompson JL, Taylor G, Gray S, Johansen-Berg H, Bilzon JLJ, et al (2022). Cost-effectiveness of a physical activity and behaviour maintenance programme on functional mobility decline in older adults: an economic evaluation of the REACT (Retirement in Action) trial. Lancet Public Health, 7(4), e327-e334. Abstract.  Author URL.
Ryan NAJ, Snowsill T, McKenzie E, Monahan KJ, Nebgen D (2021). Should women with Lynch syndrome be offered gynaecological cancer surveillance?. BMJ-BRITISH MEDICAL JOURNAL, 374  Author URL.
Peters J, Snowsill T, Griffin E, Robinson S, Hyde C (2021). Variation in Model-Based Economic Evaluations of Low Dose Computed Tomography (LDCT) Screening for Lung Cancer: a Methodological Review. Value in Health
Snowsill T, Ryan N, Crosbie E (2020). Cost-effectiveness of the Manchester approach to identifying Lynch syndrome in women with endometrial cancer. Journal of Clinical Medicine, 9(6), 1664-1664.
White BE, Mujica-Mota R, Snowsill T, Gamper EM, Srirajaskanthan R, Ramage JK (2020). Evaluating cost-effectiveness in the management of neuroendocrine neoplasms. Reviews in Endocrine and Metabolic Disorders, 22(3), 647-663. Abstract.
Griffin E, Hyde C, Long L, Varley-Campbell J, Coelho H, Robinson S, Snowsill T (2020). LUNG CANCER SCREENING BY LOW-DOSE COMPUTERISED TOMOGRAPHY: a COST EFFECTIVENESS ANALYSIS OF ALTERNATIVE PROGRAMMES IN THE UNITED KINGDOM USING a NEWLY DEVELOPED NATURAL HISTORY BASED ECONOMIC MODEL. VALUE IN HEALTH, 23, S66-S66.  Author URL.
Griffin E, Hyde C, Long L, Varley-Campbell J, Coelho H, Robinson S, Snowsill T (2020). Lung cancer screening by low-dose computed tomography: a cost-effectiveness analysis of alternative programmes in the UK using a newly developed natural history-based economic model. Diagnostic and Prognostic Research, 4(1). Abstract.
Griffin E, Hyde C, Long L, Varley-Campbell J, Coelho H, Robinson S, Snowsill T (2020). PCN248 LUNG CANCER SCREENING BY LOW-DOSE COMPUTERISED TOMOGRAPHY: a COST EFFECTIVENESS ANALYSIS OF ALTERNATIVE PROGRAMMES IN THE UNITED KINGDOM USING a NEWLY DEVELOPED NATURAL HISTORY BASED ECONOMIC MODEL. Value in Health, 23
Withall J, Greaves CJ, Thompson JL, de Koning JL, Bollen JC, Moorlock SJ, Fox KR, Western MJ, Snowsill T, Medina-Lara A, et al (2020). The Tribulations of Trials: Lessons Learnt Recruiting 777 Older Adults into REtirement in ACTion (REACT), a Trial of a Community, Group-Based Active Aging Intervention Targeting Mobility Disability. J Gerontol a Biol Sci Med Sci, 75(12), 2387-2395. Abstract.  Author URL.
Snowsill T (2019). A New Method for Model-Based Health Economic Evaluation Utilizing and Extending Moment-Generating Functions. Medical Decision Making, 39(5), 523-539. Abstract.
Snowsill TM, Ryan NAJ, Crosbie EJ, Frayling IM, Evans DG, Hyde CJ (2019). Cost-effectiveness analysis of reflex testing for Lynch syndrome in women with endometrial cancer in the UK setting. PLoS ONE
Yang H, Varley-Campbell J, Coelho H, Long L, Robinson S, Snowsill T, Griffin E, Peters J, Hyde C (2019). Do we know enough about the effect of low-dose computed tomography screening for lung cancer on survival to act? a systematic review, meta-analysis and network meta-analysis of randomised controlled trials. Diagnostic and Prognostic Research, 3(1). Abstract.
Kang Y-J, Killen J, Caruana M, Simms K, Taylor N, Frayling I, Snowsill TM, Huxley N, Coupé V, Hughes S, et al (2019). The effectiveness and the cost-effectiveness of systematic testing for Lynch syndrome in incident colorectal cancer cases in Australia. Medical Journal of Australia, 212, 72-81.
Varley-Campbell J, Mujica Mota R, Coelho H, Ocean N, Barnish M, Packman D, Dodman S, Cooper C, Snowsill TM, Kay T, et al (2019). Three biomarker tests to help diagnose preterm labour: a systematic review and economic evaluation. Health Technology Assessment, 23(13).
Tikhonova I, Huxley N, Snowsill T, Crathorne L, Varley-Campbell J, Napier M, Hoyle M (2018). Economic Analysis of First-Line Treatment with Cetuximab or Panitumumab for RAS Wild-Type Metastatic Colorectal Cancer in England. Pharmacoeconomics
Yang H, Snowsill T, Griffin E, Long L, Varley-Campbell J, Coelho H, Robinson S, Hyde C (2018). Low-dose computed tomography for lung cancer screening in high-risk populations: a systematic review and economic evaluation. Health Technology Assessment, 22(69), 1-276. Abstract.
Coelho H, Jones-Hughes T, Snowsill T, Briscoe S, Huxley N, Frayling IM, Hyde C (2017). A systematic review of test accuracy studies evaluating molecular micro-satellite instability testing for the detection of individuals with lynch syndrome. BMC Cancer, 17(1). Abstract.
Tikhonova IA, Hoyle MW, Snowsill TM, Cooper C, Varley-Campbell JL, Rudin CE, Mujica Mota RE (2017). Azacitidine for Treating Acute Myeloid Leukaemia with More Than 30 % Bone Marrow Blasts: an Evidence Review Group Perspective of a National Institute for Health and Care Excellence Single Technology Appraisal. PharmacoEconomics, 35(3), 363-373. Abstract.
Snowsill TM, Moore J, Mota REM, Peters JL, Jones-Hughes TL, Huxley NJ, Coelho HF, Haasova M, Cooper C, Lowe JA, et al (2017). Immunosuppressive agents in adult kidney transplantation in the National Health Service: a model-based economic evaluation. Nephrology Dialysis Transplantation, 32(7), 1251-1259. Abstract.
Snowsill T, Coelho H, Huxley N, Jones-Hughes T, Briscoe S, Frayling IM, Hyde C (2017). Molecular testing for Lynch syndrome in people with colorectal cancer: Systematic reviews and economic evaluation. Health Technology Assessment, 21(51), 1-238. Abstract.
Huxley N, Crathorne L, Varley-Campbell J, Tikhonova I, Snowsill T, Briscoe S, Peters J, Bond M, Napier M, Hoyle M, et al (2017). The clinical effectiveness and cost-effectiveness of cetuximab (review of technology appraisal no. 176) and panitumumab (partial review of technology appraisal no. 240) for previously untreated metastatic colorectal cancer: a systematic review and economic evaluation. Health Technology Assessment, 21(38), V-241. Abstract.
Jones-Hughes T, Snowsill T, Haasova M, Coelho H, Crathorne L, Cooper C, Mujica-Mota R, Peters J, Varley-Campbell J, Huxley N, et al (2016). Immunosuppressive therapy for kidney transplantation in adults: a systematic review and economic model. Health Technology Assessment, 20(62), 1-594. Abstract.
Haasova M, Snowsill T, Jones-Hughes T, Crathorne L, Cooper C, Varley-Campbell J, Mujica-Mota R, Coelho H, Huxley N, Lowe J, et al (2016). Immunosuppressive therapy for kidney transplantation in children and adolescents: Systematic review and economic evaluation. Health Technology Assessment, 20(61), 1-323. Abstract.
Crathorne L, Huxley N, Haasova M, Snowsill T, Jones-Hughes T, Hoyle M, Briscoe S, Coelho H, Long L, Medina-Lara A, et al (2016). The effectiveness and cost-effectiveness of erythropoiesis-stimulating agents (epoetin and darbepoetin) for treating cancer-treatment induced anaemia (including review of TA142): a systematic review and economic model. Health Technology Assessment  Author URL.
Snowsill T, Huxley N, Hoyle M, Jones-Hughes T, Coelho H, Cooper C, Frayling I, Hyde C (2015). A model-based assessment of the cost-utility of strategies to identify Lynch syndrome in early-onset colorectal cancer patients. BMC Cancer, 15 Abstract.  Author URL.
Huxley N, Jones-Hughes T, Coelho H, Snowsill T, Cooper C, Meng Y, Hyde C, Mújica-Mota R (2015). A systematic review and economic evaluation of intraoperative tests [RD-100i one-step nucleic acid amplification (OSNA) system and Metasin test] for detecting sentinel lymph node metastases in breast cancer. Health Technol Assess, 19(2), v-215. Abstract.  Author URL.
Crathorne L, Huxley N, Haasova M, Snowsill T, Jones-Hughes T, Hoyle M, Briscoe S, Coelho H, Long L, Medina-Lara A, et al (2014). 1498PWHAT IS THE CLINICAL EFFECTIVENESS OF ERYTHROPOIESIS STIMULATING AGENTS FOR THE TREATMENT OF CANCER TREATMENT-INDUCED ANAEMIA?. Ann Oncol, 25(suppl_4), iv523-iv524.  Author URL.
Snowsill T, Huxley N, Hoyle M, Jones-Hughes T, Coelho H, Cooper C, Frayling I, Hyde C (2014). A systematic review and economic evaluation of diagnostic strategies for Lynch syndrome. Health Technology Assessment, 18(58).  Author URL.
Flaounas I, Ali O, Turchi M, Snowsill T, Nicart F, De Bie T, Cristianini N (2011). NOAM: News outlets analysis and monitoring system. Proceedings of the ACM SIGMOD International Conference on Management of Data, 1275-1277. Abstract.
Snowsill T, Fyson N, De Bie T, Cristianini N (2011). Refining causality: Who copied from whom?. Proceedings of the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, 466-474. Abstract.
Snowsill T, Flaounas I, De Bie T, Cristianini N (2010). Detecting events in a million New York times articles. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 6323 LNAI(PART 3), 615-618. Abstract.
Snowsill T, Nicart F, Stefani M, De Bie T, Cristianini N (2010). Finding surprising patterns in textual data streams. 2010 2nd International Workshop on Cognitive Information Processing, CIP2010, 405-410. Abstract.
Turchi M, Flaounas I, Ali O, De Bie T, Snowsill T, Cristianini N (2009). Found in translation. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 5782 LNAI(PART 2), 746-749. Abstract.

Conferences

Paulden M, Snowsill T, O'Mahony J, McCabe C (2021). ARE THE 'EQUAL VALUE OF LIFE YEARS GAINED' AND 'HEALTH YEARS IN TOTAL' APPROACHES VIABLE ALTERNATIVES TO THE QALY? MATTERS OF LOGIC AND MATTERS OF VALUE.  Author URL.
Snowsill T (2021). PROPAGATION OF UNCERTAINTY THROUGH ECONOMIC MODELS USING TAYLOR SERIES APPROXIMATIONS: THE DELTA-PSA (Δ-PSA) METHOD.  Author URL.
Tikhonova IA, Hoyle M, Snowsill T, Cooper C, Varley-Campbell J, Rudin C, Mujica Mota R (2016). Azacitidine for Treating Acute Myeloid Leukaemia: a Nice Single Technology Appraisal. ISPOR.
Tikhonova IA, Hoyle M, Snowsill T, Crathorne L, Varley-Campbell J, Peters J, Briscoe S, Bond M, Huxley N (2016). Cost Effectiveness of Cetuximab and Panitumumab for First-Line RAS WT Metastatic Colorecal Cancer. ISPOR.
Haasova M, Jones-Hughes T, Peters J, Snowsill T, Coelho H, Crathorne L, Mujica Mota R, Varley-Campbell J, Huxley N, Moore J, et al (2016). Immunosuppressive therapy for renal transplantation in adults: a systematic review and network meta-analyses. Health Technology
Assessment international (HTAi). 10th - 14th May 2016. Abstract.
Huxley N, Snowsill T, Hoyle M, Crathorne L, Haasova M, Briscoe S, Coelho H, Medina-Lara A, Mujica-Mota R, Napier M, et al (2014). A COST-EFFECTIVENESS ANALYSIS OF ERYTHROPOIESIS-STIMULATING AGENTS FOR TREATING CANCER-TREATMENT INDUCED ANAEMIA.  Author URL.
Snowsill T, Huxley N, Hoyle M, Crathorne L, Haasova M, Briscoe S, Coelho H, Medina-Lara A, Mota MR, Napier M, et al (2014). MODEL-BASED COST-UTILITY ANALYSIS OF ERYTHROPOIESIS-STIMULATING AGENTS FOR THE TREATMENT OF CANCER-TREATMENT INDUCED ANAEMIA IN THE UK NHS.  Author URL.
Huxley N, Snowsill T, Hoyle M, Jones-Hughes T, Coelho H, Cooper C, Frayling I, Hyde C (2013). COST-EFFECTIVENESS OF SYSTEMATIC TESTING FOR LYNCH SYNDROME IN PATIENTS NEWLY DIAGNOSED WITH COLORECTAL CANCER IN THE UNITED KINGDOM.  Author URL.

Reports

Lee D, Muthukumar M, Lovell A, Farmer C, Burns D, Matthews J, Coelho H, O'Toole B, Trigg L, Snowsill T, et al (2023). Treatments for renal cell carcinoma [ID 6186]: a pathways pilot appraisal.
Barnish M, Varley-Campbell J, Coelho H, Dodman S, Snowsill T, Mujica-Mota R, Packman D, Ocean N, Kay T, Liversedge N, et al (2018). Biomarker tests to help diagnose preterm labour in symptomatic women with intact membranes: a systematic review.
Snowsill TM, Landa P, Dethridge B, Medina-Lara A (2018). Methods for modelling the cost-effectiveness of interventions for prostate cancer: a systematic review - Protocol. Abstract.

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