Evaluating the Quality of Decisionmaking for Diagnostic Tests: A Methodological Misadventure

Abstract

This issue of Annals contains an article about evaluating hospitals’ use of computed tomography (CT) scans for patients presenting to emergency departments (EDs) with acute headache. The authors tested a system devised by the Centers for Medicare & Medicaid Services (CMS) to measure the number of unwarranted CT scans, an intent that responds to the increasing number of brain CT scans being obtained in EDs. The purpose of this editorial is to describe the system used by CMS, summarize its performance, and suggest better solutions to the problem that CMS is trying to address. This program is part of a CMS initiative to identify poorquality decisionmaking about imaging tests in hospitalassociated outpatient services. The CMS has a statutory requirement to collect outpatient quality measures from hospitals and to make the findings public. Rather than require hospitals to report the results of their quality measurements to CMS, the agency uses Medicare claims data, which include the name of the hospital and the ordering clinician, the identity of the imaging procedure and other tests, and, as a proxy for clinical data, the primary and secondary diagnoses. The CMS initiative will also track the use of abdominal CT with contrast, thoracic CT or magnetic resonance imaging (MRI) with contrast, follow-up of mammograms, simultaneous use of brain and sinus CT scans, lumbar spine CT or MRI for back pain, and cardiac testing for risk assessment before low-risk noncardiac surgery. The agency’s stated goal is to reduce “waste,” to reduce unnecessary exposure to radiation and contrast dye, and to increase adherence to evidence-based practice. CMS will report the results to the public on Hospital Compare, a consumer-oriented Web site. The CMS “efficiency measure” of head CT use in ED patients with acute headache is the proportion of such patients who had an uncalled-for same-day brain CT scan. To be included, patients must have had a headache diagnosis code for tension headaches, migraine headaches, cluster headaches, and other headache diagnoses that can be readily diagnosed without brain imaging. The CMS appears to be seeking a measure of CT scan use when the patient does not have one of the widely accepted indications for imaging in headache patients (eg, s