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Featured researches published by Dionysios Ntais.


Health Technology Assessment | 2015

Calculating when elective abdominal aortic aneurysm repair improves survival for individual patients: development of the Aneurysm Repair Decision Aid and economic evaluation

Stuart W. Grant; Matthew Sperrin; Eric Carlson; Natasha Chinai; Dionysios Ntais; Matthew Hamilton; Graham Dunn; Iain Buchan; Linda Davies; Charles McCollum

BACKGROUND Abdominal aortic aneurysm (AAA) repair aims to prevent premature death from AAA rupture. Elective repair is currently recommended when AAA diameter reaches 5.5 cm (men) and 5.0 cm (women). Applying population-based indications may not be appropriate for individual patient decisions, as the optimal indication is likely to differ between patients based on age and comorbidities. OBJECTIVE To develop an Aneurysm Repair Decision Aid (ARDA) to indicate when elective AAA repair optimises survival for individual patients and to assess the cost-effectiveness and associated uncertainty of elective repair at the aneurysm diameter recommended by the ARDA compared with current practice. DATA SOURCES The UK Vascular Governance North West and National Vascular Database provided individual patient data to develop predictive models for perioperative mortality and survival. Data from published literature were used to model AAA growth and risk of rupture. The cost-effectiveness analysis used data from published literature and from local and national databases. METHODS A combination of systematic review methods and clinical registries were used to provide data to populate models and inform the structure of the ARDA. Discrete event simulation (DES) was used to model the patient journey from diagnosis to death and synthesised data were used to estimate patient outcomes and costs for elective repair at alternative aneurysm diameters. Eight patient clinical scenarios (vignettes) were used as exemplars. The DES structure was validated by clinical and statistical experts. The economic evaluation estimated costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) from the NHS, social care provider and patient perspective over a lifetime horizon. Cost-effectiveness acceptability analyses and probabilistic sensitivity analyses explored uncertainty in the data and the value for money of ARDA-based decisions. The ARDA outcome measures include perioperative mortality risk, annual risk of rupture, 1-, 5- and 10-year survival, postoperative long-term survival, median life expectancy and predicted time to current threshold for aneurysm repair. The primary economic measure was the ICER using the QALY as the measure of health benefit. RESULTS The analysis demonstrated it is feasible to build and run a complex clinical decision aid using DES. The model results support current guidelines for most vignettes but suggest that earlier repair may be effective in younger, fitter patients and ongoing surveillance may be effective in elderly patients with comorbidities. The model adds information to support decisions for patients with aneurysms outside current indications. The economic evaluation suggests that using the ARDA compared with current guidelines could be cost-effective but there is a high level of uncertainty. LIMITATIONS Lack of high-quality long-term data to populate all sections of the model meant that there is high uncertainty about the long-term clinical and economic consequences of repair. Modelling assumptions were necessary and the developed survival models require external validation. CONCLUSIONS The ARDA provides detailed information on the potential consequences of AAA repair or a decision not to repair that may be helpful to vascular surgeons and their patients in reaching informed decisions. Further research is required to reduce uncertainty about key data, including reintervention following AAA repair, and assess the acceptability and feasibility of the ARDA for use in routine clinical practice. FUNDING The National Institute for Health Research Health Technology Assessment programme.


BMJ Open | 2016

Long-term cost-effectiveness of collaborative care (vs usual care) for people with depression and comorbid diabetes or cardiovascular disease: a Markov model informed by the COINCIDE randomised controlled trial

Elizabeth Camacho; Dionysios Ntais; Peter Coventry; Peter Bower; Karina Lovell; Carolyn Chew-Graham; Clare Baguley; Linda Gask; Chris Dickens; Linda Davies

Objectives To evaluate the long-term cost-effectiveness of collaborative care (vs usual care) for treating depression in patients with diabetes and/or coronary heart disease (CHD). Setting 36 primary care general practices in North West England. Participants 387 participants completed baseline assessment (collaborative care: 191; usual care: 196) and full or partial 4-month follow-up data were captured for 350 (collaborative care: 170; usual care: 180). 62% of participants were male, 14% were non-white. Participants were aged ≥18 years, listed on a Quality and Outcomes Framework register for CHD and/or type 1 or 2 diabetes mellitus, with persistent depressive symptoms. Patients with psychosis or type I/II bipolar disorder, actively suicidal, in receipt of services for substance misuse, or already in receipt of psychological therapy for depression were excluded. Intervention Collaborative care consisted of evidence-based low-intensity psychological treatments, delivered over 3 months and case management by a practice nurse and a Psychological Well Being Practitioner. Outcome measures As planned, the primary measure of cost-effectiveness was the incremental cost-effectiveness ratio (cost per quality-adjusted life year (QALY)). A Markov model was constructed to extrapolate the trial results from short-term to long-term (24 months). Results The mean cost per participant of collaborative care was £317 (95% CI 284 to 350). Over 24 months, it was estimated that collaborative care was associated with greater healthcare usage costs (net cost £674 (95% CI −30 953 to 38 853)) and QALYs (net QALY gain 0.04 (95% CI −0.46 to 0.54)) than usual care, resulting in a cost per QALY gained of £16 123, and a likelihood of being cost-effective of 0.54 (willingness to pay threshold of £20 000). Conclusions Collaborative care is a potentially cost-effective long-term treatment for depression in patients with comorbid physical and mental illness. The estimated cost per QALY gained was below the threshold recommended by English decision-makers. Further, long-term primary research is needed to address uncertainty associated with estimates of cost-effectiveness. Trial registration number ISRCTN80309252; Post-results.


British Journal of Dermatology | 2015

Psoriasis treatment and management – a systematic review of full economic evaluations

Matthew Hamilton; Dionysios Ntais; C.E.M. Griffiths; Linda Davies

Psoriasis frequently requires lifetime control and current therapies vary significantly in price. High‐quality economic evaluations are necessary to determine if higher‐cost treatments are value for money.


Journal of Affective Disorders | 2017

Cost-effectiveness of structured group psychoeducation versus unstructured group support for bipolar disorder: Results from a multi-centre pragmatic randomised controlled trial

Elizabeth Camacho; Dionysios Ntais; Steven Jones; Lisa Riste; Richard Morriss; Fiona Lobban; Linda Davies

BACKGROUND Bipolar disorder (BD) costs the English economy an estimated £5.2billion/year, largely through incomplete recovery. This analysis estimated the cost-effectiveness of group psychoeducation (PEd), versus group peer support (PS), for treating BD. METHODS A 96-week pragmatic randomised controlled trial (RCT), conducted in NHS primary care. The primary analysis compared PEd with PS, using multiple imputed datasets for missing values. An economic model was used to compare PEd with treatment as usual (TAU). The perspective was Health and Personal Social Services. RESULTS Participants receiving PEd (n=153) used more (costly) health-related resources than PS (n=151) (net cost per person £1098 (95% CI, £252-£1943)), with a quality-adjusted life year (QALY) gain of 0.023 (95% CI, 0.001-0.056). The cost per QALY gained was £47,739. PEd may be cost-effective (versus PS) if decision makers are willing to pay at least £37,500 per QALY gained. PEd costs £10,765 more than PS to avoid one relapse. The economic model indicates that PEd may be cost-effective versus TAU if it reduces the probability of relapse (by 15%) or reduces the probability of and increases time to relapse (by 10%). LIMITATIONS Participants were generally inconsistent in attending treatment sessions and low numbers had complete cost/QALY data. Factors contributing to pervasive uncertainty of the results are discussed. CONCLUSIONS This is the first economic evaluation of PEd versus PS in a pragmatic trial. PEd is associated with a modest improvement in health status and higher costs than PS. There is a high level of uncertainty in the data and results.


Dermatological Nursing. 2015;14(4):37-44. | 2015

The IMPACT Programme in Psoriasis: Phase I - where we are now and future directions

Pauline Nelson; Darren M. Ashcroft; Christine Bundy; Carolyn Chew-Graham; Anna Chisholm; Lis Cordingley; Linda Davies; Jamie Elvidge; Cem Griffiths; Matthew Hamilton; R. Hilton; K. Kane; Christopher Keyworth; Alison Littlewood; Karina Lovell; Helen McAteer; Dionysios Ntais; Rosa Parisi; C. Pearce; Martin K. Rutter; Deborah Symmons; Helen S. Young


Programme Grants for Applied Research | 2018

Reducing relapse and suicide in bipolar disorder: practical clinical approaches to identifying risk, reducing harm and engaging service users in planning and delivery of care – the PARADES (Psychoeducation, Anxiety, Relapse, Advance Directive Evaluation and Suicidality) programme

Steven Jones; Lisa Riste; Christine Barrowclough; Peter Bartlett; Caroline Clements; Linda Davies; Fiona Holland; Nav Kapur; Fiona Lobban; Rita Long; Richard Morriss; Sarah Peters; Chris Roberts; Elizabeth Camacho; Lynsey Gregg; Dionysios Ntais


Programme Grants for Applied Research | 2017

CHOICE: Choosing Health Options in Chronic Care Emergencies

Elspeth Guthrie; Cara Afzal; Claire Blakeley; Amy Blakemore; Rachel Byford; Elizabeth Camacho; Tom Chan; Carolyn Chew-Graham; Linda Davies; Simon de Lusignan; Chris Dickens; Jessica Drinkwater; Graham Dunn; Cheryl Hunter; Mark Joy; Navneet Kapur; Susanne Langer; Karina Lovell; Jackie Macklin; Kevin Mackway-Jones; Dionysios Ntais; Peter Salmon; Barbara Tomenson; Jennifer Watson


Archive | 2015

Excluded and included economic studies

Stuart W Grant; Matthew Sperrin; Eric Carlson; Natasha Chinai; Dionysios Ntais; Matthew Hamilton; Graham Dunn; Iain Buchan; Linda Davies; Charles N McCollum


Archive | 2015

Meeting dates of study committees

Stuart W Grant; Matthew Sperrin; Eric Carlson; Natasha Chinai; Dionysios Ntais; Matthew Hamilton; Graham Dunn; Iain Buchan; Linda Davies; Charles N McCollum


Archive | 2015

Patient and surgeon information

Stuart W Grant; Matthew Sperrin; Eric Carlson; Natasha Chinai; Dionysios Ntais; Matthew Hamilton; Graham Dunn; Iain Buchan; Linda Davies; Charles N McCollum

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Linda Davies

University of Manchester

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Graham Dunn

University of Manchester

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Eric Carlson

University of Manchester

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Iain Buchan

University of Manchester

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Charles N McCollum

Manchester Academic Health Science Centre

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Stuart W Grant

Manchester Academic Health Science Centre

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