Constructing a Measure of Anesthesia Intensity Using Cross-Sectional Claims Data

Abstract

With intensifying emphasis on episodes of care and bundled payments for surgical admissions, anesthesia expenditures are increasingly important in assessing variation in expenditures for surgical episodes. When comparing anesthesia expenditures across surgical settings, adjustment for anesthesia case complexity and duration of anesthesia services, also known as anesthesia service intensity, is desirable. A single anesthesia intensity measure allows researchers to make more direct comparisons between anesthesia outcomes across settings and services. We describe a process for creating a claims-based anesthesia intensity measure using Medicare claims. We create the measure using two fields: base units associated with American Medical Association Current Procedural Terminology codes on the anesthesia claim and time units associated with the service. We rescaled the time component of the anesthesia intensity measure to equally represent base units and time units. For illustration, we applied the measure to Medicare anesthesia expenditures stratified by rural/urban location. We found that adjustments for intensity were greater in urban settings because the level of intensity is greater. Compared with rural settings, unadjusted expenditures in urban settings are roughly 26 percent higher, whereas adjusted expenditures in urban settings are only 20 percent higher. Even absent longitudinal data, researchers can adjust anesthesia outcomes for intensity using our cross-sectional claims-based intensity method.