CHAPTER 6: Costs, Outcomes, and Cost-Effectiveness in the Intensive Care Unit

KEY POINTS

• Delivery of critical care is expensive, although exact costs are challenging to estimate.

• Mortality is the most commonly reported outcome in trials of critical care interventions; however, as with all outcome measures of critical illness, it has important limitations.

• Cost-effectiveness analysis (CEA), and the special subset of cost-utility analysis (CUA), is endorsed by multiple national and international critical care groups as appropriate methods for assessing the value of critical care interventions.

• The QALY (quality-adjusted life year) is the most common measure of health benefit used in CEAs, combining duration of survival and quality of life into a single measure.

INTRODUCTION

Critical care represents a disproportionately large share of health care costs, particularly in the United States, where health care is already the most expensive in the world.¹ In 2019, national health expenditures in the United States were estimated to be $3.8 trillion, accounting for 17.7% of the gross domestic product (GDP).² Intensive care units (ICUs), where the majority of critical care delivery occurs, consume more than 20% of total hospital costs despite accounting for only 10% of hospital beds, with many critical care interventions of unclear effectiveness.³ Furthermore, ICU utilization and costs have continuously increased in the United States over the last three decades.⁴ While some countries have adopted a cost-effectiveness threshold for national health systems,^5–8 the use of cost-effectiveness evaluations in the United States has been variable,^9–11 with federal agencies prohibited from using them in resource allocation decisions.^12–14 However, a growing emphasis on comparative effectiveness and cost transparency has led to a proliferation of data about cost valuation of different medical interventions,^15–17 and movements to reduce the use of low-value care.^18–20 This chapter will review the methods for evaluating the costs and value of critical care. It will summarize how costs are estimated, at both macro and micro levels; discuss outcome measurement in critical care; provide an overview of methodologies for putting costs and outcomes together to evaluate the cost-effectiveness of specific treatments; and review the existing literature on cost-effectiveness in critical care.

COSTS OF ICU CARE

The proportion of health care costs that can be attributed to critical care is substantial and increasing. For example, between 2000 and 2010 in the United States, the number of ICU beds increased by 18% (88,235-103,900), while the number of hospital beds actually decreased by 2% (655,785-641,395).⁴ By one estimate, during the same period, annual critical care costs nearly doubled from $56 to $108 billion—a 32% increase in the proportion of GDP consumed by critical care (0.54%-0.72%).⁴ Although the United States is an outlier in health care costs overall, and studies have demonstrated international variability in resource utilization attributable to ICUs,^21,22 the idea that provision of critical care is expensive is universally accepted.

Therefore, it is important to evaluate the costs ...