The Cost-Effectiveness of Providing DAFNE to Subgroups of Predicted Responders - PowerPoint Presentation

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The Cost-Effectiveness of Providing DAFNE to Subgroups of Predicted Responders

J Kruger1, A Brennan1, P Thokala1, S Heller2 on behalf of the DAFNE Research Group

1 School of Health and Related Research (ScHARR), University of Sheffield, Sheffield2 Academic Unit of Diabetes, Endocrinology and Metabolism, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield

Introduction The Dose Adjustment for Normal Eating (DAFNE) course is a structured education programme for adult patients with Type 1 diabetes. DAFNE has been found to improve glycosylated haemoglobin (HbA1c) levels in UK Type 1 diabetes patients1 and a cost-effectiveness modelling analysis concluded that DAFNE was cost-effective from the NHS perspective2. This analysis assumed that HbA1c benefit experienced by patients receiving DAFNE was homogeneous, however it has been found that HbA1c response to DAFNE is highly variable between patients. Although some patients do experience significant HbA1c reductions after DAFNE, other patients experience a worsening of HbA1c1,3 and some find it difficult to maintain initial HbA1c improvements4. Targeting DAFNE to only those patients that are expected to benefit may improve the cost-effectiveness of the intervention.This study aims to explore statistical modelling methodologies to predict individual clinical responses to DAFNE from psychosocial characteristics and incorporate psychosocial predictors into an economic simulation model to investigate the cost-effectiveness of providing DAFNE to subgroups of predicted responders.

MethodsData from the National Institute for Health Research (NIHR) DAFNE Research Programme were used to support all analyses*. In the psychosocial sub-study of the NIHR DAFNE Research Programme demographic, psychosocial and clinical data were collected from 262 patients at baseline and 3-, 6-, and 12-months after DAFNE.Three regression models were used to investigate the relationships between patients’ baseline demographic and psychosocial characteristics and 12-month HbA1c response to DAFNE:The regression prediction models were integrated with a patient level simulation model of Type 1 diabetes. The integrated model was used to compare provision of DAFNE only to those patients who were predicted from their baseline characteristics to experience a 12-month HbA1c reduction of at least 0.5% with current practice. The model estimated costs and quality-adjusted life-years (QALYs) over a 50-year time horizon from an NHS perspective. Costs and QALYs were discounted at a rate of 3.5%.

ConclusionsThe results suggest that screening patients prior to offering them DAFNE and providing the intervention only to predicted responders is not cost-effective. The adapted health economic model offers the opportunity to investigate research questions about the cost-effectiveness of DAFNE that could not be assessed using previously published cost-effectiveness models of Type 1 diabetes. The model could be used to evaluate and compare future developments of the DAFNE intervention.

ResultsBaseline HbA1c, baseline fear of hypoglycaemia5, baseline thoughts about diabetes seriousness6, BMI and gender were found to be significantly predictive (p<0.05) of 12-month HbA1c change after DAFNE. The adjusted R2 of prediction model A was 0.534 and of prediction model B was 0.054. Prediction model C correctly categorised 86.6% of non-responders and 35.2% of responders.The results suggest that providing DAFNE only to a subgroup of predicted responders generates fewer QALYs for higher costs and is therefore dominated by current practice (see Figure 1). The results were insensitive to the treatment response prediction model used and to alternative model assumptions tested in one-way sensitivity-analysis.

ReferencesDAFNE Study Group, Training in flexible, intensive insulin management to enable dietary freedom in people with type 1 diabetes: dose adjustment for normal eating (DAFNE) randomised controlled trial. British Medical Journal 2002;325:746-749.Shearer A., Bagust A, Sanderson D, Heller S, Roberts S. Effectiveness of flexible intensive insulin management to enable dietary freedom in people with type1 diabetes in the UK. Diabetic Medicine 2004;21:460–467.DAFNE NIHR Research Group. Personal communication: Unpublished data. 2006.Speight J, Amiel S, Bradley C, Heller S, Oliver L, Roberts S, et al. Long-term biomedical and psychosocial outcomes following DAFNE (Dose Adjustment For Normal Eating) structured education to promote intensive insulin therapy in adults with sub-optimally controlled Type 1 diabetes. Diabetes Research and Clinical Practice 2010;89:22-9.Cox D, Irvine A, Gonder-Frederick L, Nowacek G, Butterfield J. Fear of hypoglycemia: quantification, validation, and utilization. Diabetes Care 1987;10(5):617-21.Hampson S, Glasgow R, Toobert D. Personal Models of Diabetes and Their Relations to Self-Care Activities. Health Psychology 1990;9(5):632-46.

* This study was funded by the NIHR. This poster presents independent research commissioned by the NIHR under Improving management of Type 1 diabetes in the UK: the DAFNE programme as a research test-bed. The views expressed in this poster are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

Figure 1

: The cost-effectiveness of providing DAFNE only to predicted responders vs. current practice

AcknowledgementsWe would like to thank our collaborators Dr Debbie Cooke and Dr Marie Clark at University College London and Dr Rod Bond at University of Sussex for sharing data and preliminary research findings from the psychosocial sub-study of the NIHR DAFNE Research Programme.

Prediction model

Definition

of treatment response

Statistical analysis method

A

12-month HbA

1c

value

Multiple

linear regression

B

Change in HbA

1c

from baseline to 12-months

Multiple

linear regression

C

Probability of responding to DAFNE (reduction of at least 0.5% by 12 months)

Logistic regression