Cost-effectiveness analysis: some clarifications

Cost-effectiveness modelling in diagnostic imaging: a stepwise approach

Abstract

Diagnostic imaging (DI) is the fastest growing sector in medical expenditures and takes a central role in medical decision-making. The increasing number of various and new imaging technologies induces a growing demand for cost-effectiveness analysis (CEA) in imaging technology assessment. In this article we provide a comprehensive framework of direct and indirect effects that should be considered for CEA in DI, suitable for all imaging modalities. We describe and explain the methodology of decision analytic modelling in six steps aiming to transfer theory of CEA to clinical research by demonstrating key principles of CEA in a practical approach. We thereby provide radiologists with an introduction to the tools necessary to perform and interpret CEA as part of their research and clinical practice.

Key Points

• DI influences medical decision making, affecting both costs and health outcome.

• This article provides a comprehensive framework for CEA in DI.

• A six-step methodology for conducting and interpreting cost-effectiveness modelling is proposed.

Systematic review, critical appraisal, and analysis of the quality of economic evaluations in stroke imaging

BACKGROUND AND PURPOSE

This study reviews the quality of economic evaluations of imaging after acute stroke and identifies areas for improvement.

METHODS

We performed full-text searches of electronic databases that included Medline, Econlit, the National Health Service Economic Evaluation Database, and the Tufts Cost Effectiveness Analysis Registry through July 2012. Search strategy terms included the following: stroke*; cost*; or cost-benefit analysis*; and imag*. Inclusion criteria were empirical studies published in any language that reported the results of economic evaluations of imaging interventions for patients with stroke symptoms. Study quality was assessed by a commonly used checklist (with a score range of 0% to 100%).

RESULTS

Of 568 unique potential articles identified, 5 were included in the review. Four of 5 articles were explicit in their analysis perspectives, which included healthcare system payers, hospitals, and stroke services. Two studies reported results during a 5-year time horizon, and 3 studies reported lifetime results. All included the modified Rankin Scale score as an outcome measure. The median quality score was 84.4% (range=71.9%-93.5%). Most studies did not consider the possibility that patients could not tolerate contrast media or could incur contrast-induced nephropathy. Three studies compared perfusion computed tomography with unenhanced computed tomography but assumed that outcomes guided by the results of perfusion computed tomography were equivalent to outcomes guided by the results of magnetic resonance imaging or noncontrast computed tomography.

CONCLUSIONS

Economic evaluations of imaging modalities after acute ischemic stroke were generally of high methodological quality. However, important radiology-specific clinical components were missing from all of these analyses.

Cost-effectiveness of CTA, MRA and DSA in patients with non-traumatic subarachnoid haemorrhage

Objectives

Intra-arterial digital subtraction angiography (DSA), magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) are imaging modalities used for diagnostic work-up of non-traumatic subarachnoid haemorrhage. The aim of our study was to compare the cost-effectiveness of MRA, DSA and CTA in the first year after the bleed.

Methods

A decision model was used to calculate costs and benefits (in quality-adjusted life-years [QALYs]) that accrued to cohorts of 1,000 patients. Costs and characteristics of diagnostic tests, therapy, patients’ quality of life and associated costs were respected. The diagnostic strategy with highest QALYs and lowest costs was considered most cost-effective.

Results

DSA was the most effective diagnostic option, yielding on average 0.6039 QALYs (95 % CI, 0.5761–0.6327) per patient, followed by CTA 0.5983 QALYs (95 % CI, 0.5704–0.6278) and MRA 0.5947 QALYs (95 % CI, 0.5674–0.6237). Cost was lowest for DSA (39,808 €; 95 % CI, 37,182–42,663), followed by CTA (40,748 €; 95 % CI, 37,937–43,831) and MRA (41,814 €; 95 % CI, 38,730–45,146). A strategy of CTA followed by DSA if CTA was negative or coiling deemed not feasible, was as effective as DSA alone at average costs of 39,767€ (95 % CI, 36,903–42,402).

Conclusion

A combined strategy of CTA and DSA was found to be the most cost-effective diagnostic approach.

Main Messages

• We defined a standard model for cost-effectiveness analysis in diagnostic imaging.

• Comparing total 1-year health costs and benefits, CTA is superior to MRA.

• A strategy of combining CTA and DSA was found to be the most cost-effective diagnostic approach.

Economic evaluation in radiology: reviewing the literature and examples in oncology

RATIONALE AND OBJECTIVES

To review US health care trends related to medical imaging utilization and costs as well as to present standard methods for conducting economic evaluation for health care interventions and medical imaging specifically.

MATERIALS AND METHODS

A review of the medical literature was performed to assess health policy and health technology assessment trends, expenditures, and cost-effectiveness analysis (CEA) related to medical imaging. Standard approaches to conducting economic evaluation and cost-effectiveness analysis were reviewed and summarized. Examples of CEA evidence related to imaging in select oncology conditions were presented.

RESULTS

Several high-quality methodology publications have provided guidance for conducting economic evaluation and CEA in radiology. There is variability in the quality of CEA models and their dissemination. However, there are numerous methodologically sound cost-effectiveness analyses for radiology procedures, and the evidence base of CEA studies for medical imaging continues to increase. Advanced imaging approaches for diagnosing and staging oncology conditions have the potential to provide cost-effective care when used in appropriate patient subpopulations.

CONCLUSIONS

Additional rigorous comparative effectiveness studies for advanced imaging, including cost-effectiveness analyses, can provide useful information to policy makers and health care providers on the relative effects and costs associated with diagnostic alternatives.

Evidence-based radiology: why and how?

PURPOSE

To provide an overview of evidence-based medicine (EBM) in relation to radiology and to define a policy for adoption of this principle in the European radiological community.

RESULTS

Starting from Sackett's definition of EBM we illustrate the top-down and bottom-up approaches to EBM as well as EBM's limitations. Delayed diffusion and peculiar features of evidence-based radiology (EBR) are defined with emphasis on the need to shift from the demonstration of the increasing ability to see more and better, to the demonstration of a significant change in treatment planning or, at best, of a significant gain in patient outcome. The "as low as reasonably achievable" (ALARA) principle is thought as a dimension of EBR while EBR is proposed as part of the core curriculum of radiology residency. Moreover, we describe the process of health technology assessment in radiology with reference to the six-level scale of hierarchy of studies on diagnostic tests, the main sources of bias in studies on diagnostic performance, and levels of evidence and degrees of recommendations according to the Centre for Evidence-Based Medicine (Oxford, UK) as well as the approach proposed by the GRADE working group. Problems and opportunities offered by evidence-based guidelines in radiology are considered. Finally, we suggest nine points to be actioned by the ESR in order to promote EBR.

CONCLUSION

Radiology will benefit greatly from the improvement in practice that will result from adopting this more rigorous approach to all aspects of our work.