See All Evidence Sections
Economic Evaluation

Introduction

Beginning with the onset of spinal cord injury (SCI), there is a significant increase in the use of health care resources to deal with the immediate emergency and acute consequences of the injury. Later the focus shifts toward management of the individual’s disability, maximizing their abilities and treating ongoing secondary complications. Clinicians, health care facility administrators and policy decision-makers must have the best possible evidence to provide individuals with SCI with optimal care in a cost-effective manner. Evidence for health care interventions comes in many forms. For clinicians, the appropriateness of an intervention is often determined by its clinical efficacy and safety. Health care administrators or policy decision makers may additionally consider ethical and economic evidence. The focus of this review is on the economics evidence for SCI rehabilitation.

Economic Evaluation Studies

Economic evaluations (also known as cost-effectiveness studies) of health care interventions are important in decision making because of limited available health care resources. Economic analysis has been defined as “the comparative analysis of alternative courses of action in terms of both their costs and consequences.” (Drummond, 2001; as described in Shemilt, 2009, pg 15.2). In health care a certain condition may have direct costs, such as hospital stay, cost of a medication, or physician visits. There are also indirect costs associated with care that may need to be considered, such as lost productivity and wages due to time off from work or transportation costs associated with medical appointments. Indirect costs can be for the patient or for an informal caregiver. The purpose of the economic evaluation is to inform decision makers about the monetary value of different treatment options or to provide an estimate of the impact of a disease or treatment option to the health care system.

For economic evaluations the primary aim is to explore and combine both the incremental cost as well as the incremental effect of a treatment against a reasonable comparator. Although often used as a “catch-all” term, economic evaluations can be grouped into three categories: cost-benefit studies, cost-effectiveness studies and cost-utility studies. In cost-benefit studies, all benefits and costs are converted to a common unit (in this case monetary costs) and summed for each intervention. Many of these benefits and costs are easily valued in terms of money (such as laboratory services consumed, or hospital bed days avoided). However, there are also many intangible items (such as patient pain or satisfaction) where assigning a monetary value may be more challenging (Morris et al., 2011). In such cases, the monetary value may be determined by patient preference, measured through their willingness to pay for the health benefits or to avoid a health cost associated with the intervention versus the comparator (Drummond, 2001; Morris et al., 2011). The output of a cost-benefit study is the difference in total monetary cost between an intervention and a comparator. In cost-effectiveness studies the benefits are not converted to a monetary value. In these types of studies, the incremental effect of the intervention is usually a clinical outcome of importance to the condition of interest. One limitation to cost-effectiveness studies is the limited comparability of these studies across different disease groups, due to variation in clinical outcomes. Cost-utility studies overcome this limitation by using a common denominator of change in health (utilities) as the clinical outcome. Utilities are measured from a generic (non-condition specific) patient preference quality of life scale. This scale measures a patient’s quality of life and assigns a value to it between 0 and 1 (Drummond, 2001). These values measured over time are multiplied by the patient’s expected life years to produce a quality-adjusted life year (QALY) value. The primary outcome of cost-utility studies reflects the incremental cost of the intervention divided by the incremental QALY gained (or lost) by the intervention. Cost-utility studies, as well as cost-effectiveness and cost-benefit analyses, provide the full spectrum of economic evaluations observed in health research publications.

Cost of Illness Studies

Another type of economic evidence that appears in the medical literature comes from cost of illness studies. Cost of illness studies, also commonly known as burden of illness studies, set out to determine the overall resource consumption associated with a specific illness. Often this is presented in monetary terms and is focused on health care resources. Originally, cost of illness studies covered all major diseases for the purposes of advocating to government for additional health care spending. Lately, studies have been narrower in scope and used for awareness of a specific disease. The purpose of disease-specific cost of illness studies is often to present the case for additional research, funding for care or raise awareness for a specific disease. Table 1 outlines the strengths and weaknesses of each type of economic study design.

Type of study How are benefits captured? Primary outcome Strengths Weaknesses
Cost Benefit Analysis As costs (often through willingness to pay) Incremental cost
  • Captures all costs and benefits in one number (cost)
  • Includes patient preference in benefit calculation
  • Whether intervention is cost effective is easy to measure
  • Least reported type of economic analysis in published literature
  • Different methods for calculating benefits
Cost
Effectiveness Analysis
Through clinical outcomes Cost per clinical outcome
  • Includes clinical outcomes that clinicians in the field are familiar with
  • Easy to incorporate clinical trial data
  • Difficult to compare across different disease groups
  • Does not incorporate quality of life/patient preferences
  • Whether intervention is cost effective requires a willingness to pay threshold
Cost Utility Analysis In the form of quality of life utilities Cost per quality-adjusted life year
  • Can compare results across different studies and disease groups
  • Widely accepted as the preferred economic evaluation by decision making bodies
  • Often utility values have not been measured
  • Different utility measurement tools provide variable results
Cost of Illness None Cost
  • Captures the economic burden of a medical condition
  • Easily understood by non-academics
  • Does not incorporate clinical outcomes or patient preferences
  • Often calculated as gross costs and not disease specific costs

With economic evidence playing an increasing role in health care decision making and government advocacy, there is a need for a review of the current state of economic research in the area of SCI. The purpose of this review was to describe the breadth of research, and to identify the current limitations and areas for future studies relevant to the SCI population. Specifically, this chapter will review the economic evaluation studies (cost-effectiveness, cost-utility and cost-benefit) and cost of illness studies in SCI.

Related Downloads
Outcome Measures