Conference Coverage

CT overutilized to diagnose appendicitis




SAN FRANCISCO – At least 25% of CT scans to diagnose appendicitis were unnecessary, potentially resulting in $1.8 million in costs at one institution and up to four new cancers from the radiation exposure, a retrospective study suggests.

The review of 1,054 patients who underwent appendectomy at the University of California, Davis, in 2005-2010 focused on costs for the patients who had high Alvarado scores, a clinical scoring system used to diagnose appendicitis, before they underwent appendectomy. CT scans to help diagnose appendicitis were performed on 77% of all patients.

Records showed that 26% of patients had an Alvarado score of 8-10, meaning that appendicitis was highly likely. CT was performed on 70% of patients with an Alvarado score of 8 and 77% of patients with a score of 9-10, comprising nearly 25% of all CT scans. That resulted in an estimated $1,813,399 in unnecessary costs for imaging, Dr. Adam Dougherty and his associates reported at the annual clinical congress of the American College of Surgeons.

Dr. Adam Dougherty

Dr. Adam Dougherty

This “overutilization” of CT scans delivered more than 4,009 mSv in unnecessary radiation exposure, averaging 19.75 mSV per scan, which is 20 times the annual limit suggested for safety, said Dr. Dougherty of the university. That excess radiation could be expected to produce up to four new cancers down the line, resulting in additional costs, he said.

The investigators also looked at the 9% of patients with low Alvarado scores, meaning that appendicitis was unlikely. CT scans were performed in 75% of patients with a score of 0-3 and 80% of patients with an Alvarado score of 4. In this subgroup, 24% showed normal/early pathology on appendectomy, which “argues against imaging and surgical treatment,” Dr. Dougherty said. The 44 CT scans in this subgroup resulted in an estimated $393,052 in unnecessary costs, he said.

That doesn’t include additional costs that could be expected from imaging, such as wait time, appendectomy and its sequelae, and potential workups of incidentalomas in the low-risk group, he added.

Previous studies have shown that a comprehensive clinical exam is as accurate as CT in diagnosing appendicitis, and that clinical assessment unaided by CT can reliably diagnose acute appendicitis, Dr. Dougherty said.

With a 72% increase in abdominal CT scans documented in other U.S. data from 2000 to 2005, he called for a “necessary, fundamental culture change” to restrain resource utilization “in order to maximize the value of the health care dollar while doing what is best for the patient.”

The investigators proposed a clinical pathway for the workup of suspected appendicitis that places greater emphasis on ultrasound imaging and conservative pathways, such as 23-hour admission for observation and next-day follow-up.

In the study, ultrasonography was underutilized across all subgroups as a viable alternative to CT scans, he said.

Dr. Dougherty reported having no financial disclosures.

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