Optimising the cost-effectiveness of risk-based screening for diabetic retinopathy

Sampson, Christopher James (2020) Optimising the cost-effectiveness of risk-based screening for diabetic retinopathy. PhD thesis, University of Nottingham.

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Abstract

Publicly provided health screening programmes tend to offer standardised screening for a fixed eligible population. Recently, the development of risk calculation engines has introduced the potential for the stratification of screening based on individuals' risks of disease onset. This possibility raises practical, methodological, and ethical challenges. To date, no such programme has been the subject of an economic evaluation. In this thesis we present reason and basis for the allocation of screening based on individual risk.

The research is conducted in the context of screening for diabetic eye disease in the UK. Diabetic retinopathy is a common complication of diabetes that can lead to blindness, substantial detriments to quality of life, and significant health care resource use. Our study is linked to a programme of research that includes a cohort study and randomised controlled trial in the city of Liverpool. We review and further develop the evidence base to inform the evaluation of a risk-based screening programme for diabetic eye disease. Specifically, we generate new evidence on the costs and health outcomes associated with the screening and treatment of diabetic retinopathy.

We report on a cross-sectional study of health-related quality of life for people attending screening for diabetic retinopathy and find that people with pre-symptomatic disease tend to report poorer quality of life than people with no disease, with EQ-5D-5L index values of 0.733 on average compared with 0.787 for people with no disease. A meta-analysis of published health state utility values for diabetic eye disease shows a negative impact on health-related quality of life before progression to blindness. Our meta-regression found a utility index decrement of 0.024 for people with proliferative retinopathy.

The costs of screening are low at the individual level, estimated to be £32.03 in our costing study. But the overall budget impact of changes in the frequency of screening can be significant. We analyse a large data set of hospital and community screening activity to identify key treatment pathways for diabetic eye disease. We find that these have changed in recent years, with the introduction of more expensive interventions.

The evidence generated by our work is used to inform the development of a decision analytic model. The model is designed to estimate the cost-effectiveness of risk-based screening for diabetic eye disease, compared with current practice. We find that risk-based screening is likely to be more cost-effective than standardised screening programmes.

Evaluating a programme that allocates screening according to individuals' levels of risk raises theoretical and ethical challenges. To this end, we develop a simple framework for individualised cost-effectiveness analysis that can be used to inform the design of a risk-based screening programme. We also explore the ethics of risk-based screening, developing the notion of screening need as distinct from treatment need.

Risk-based screening is likely to be cost-effective in the context of diabetic eye disease. The evidence presented in this thesis can be used to support the evaluation of new programmes, which can be designed in order to optimise cost-effectiveness using the methods that we describe. Such an approach is consistent with equitable policy objectives.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: James, Marilyn
Whynes, David
Keywords: Health economics, Screening, Diabetic retinopathy, Cost-effectiveness, Economic evaluation
Subjects: W Medicine and related subjects (NLM Classification) > WK Endocrine system
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 60411
Depositing User: Sampson, Christopher
Date Deposited: 17 Jul 2020 04:40
Last Modified: 17 Jul 2020 04:40
URI: http://eprints.nottingham.ac.uk/id/eprint/60411

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