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Cost-Effectiveness of Preoperative Imaging for Appendicitis After Indeterminate Ultrasonography in the Second or Third Trimester of Pregnancy

Kastenberg, Zachary J. MD; Hurley, Michael P. MS; Luan, Anna MS; Vasu-Devan, Vidya MBA; Spain, David A. MD; Owens, Douglas K. MD, MS; Goldhaber-Fiebert, Jeremy D. PhD

doi: 10.1097/AOG.0b013e3182a4a085
Original Research

OBJECTIVE: To assess the cost-effectiveness of diagnostic laparoscopy, computed tomography (CT), and magnetic resonance imaging (MRI) after indeterminate ultrasonography in pregnant women with suspected appendicitis.

METHODS: A decision-analytic model was developed to simulate appendicitis during pregnancy taking into consideration the health outcomes for both the pregnant women and developing fetuses. Strategies included diagnostic laparoscopy, CT, and MRI. Outcomes included positive appendectomy, negative appendectomy, maternal perioperative complications, preterm delivery, fetal loss, childhood cancer, lifetime costs, discounted life expectancy, and incremental cost-effectiveness ratios.

RESULTS: Magnetic resonance imaging is the most cost-effective strategy, costing $6,767 per quality-adjusted life-year gained relative to CT, well below the generally accepted $50,000 per quality-adjusted life-year threshold. In a setting where MRI is unavailable, CT is cost-effective even when considering the increased risk of radiation-associated childhood cancer ($560 per quality-adjusted life-year gained relative to diagnostic laparoscopy). Unless the negative appendectomy rate is less than 1%, imaging of any type is more cost-effective than proceeding directly to diagnostic laparoscopy.

CONCLUSIONS: Depending on imaging costs and resource availability, both CT and MRI are potentially cost-effective. The risk of radiation-associated childhood cancer from CT has little effect on population-level outcomes or cost-effectiveness but is a concern for individual patients. For pregnant women with suspected appendicitis, an extremely high level of clinical diagnostic certainty must be reached before proceeding to operation without preoperative imaging.

Magnetic resonance imaging is both the most effective and cost-effective diagnostic strategy for patients with suspected appendicitis during pregnancy after indeterminate ultrasonography.

Center for Health Policy and Center for Primary Care and Outcomes Research, Department of Medicine, and the Department of Surgery, Stanford University, Stanford, and the Veterans Affairs Palo Alto Health Care System, Palo Alto, California.

Corresponding author: Zachary J. Kastenberg, MD, Center for Health Policy and Center for Primary Care and Outcomes Research, 117 Encina Commons, Room 114, Stanford, CA 94305-6019; e-mail:

Dr. Kastenberg was supported in part by The Jack and Marion Euphrat Fellowship in Pediatric Translational Medicine (Stanford CTSA Grant Number UL1 RR025744) and by the Agency for Healthcare Research and Quality (AHRQ; Grant Number HS000028). The contents of the project are solely the responsibility of the authors and do not necessarily represent the official views of the AHRQ. Dr Owens was supported by the Department of Veterans Affairs. Dr Goldhaber-Fiebert was supported in part by a National Institutes of Health National Institute on Aging Career Development Award (K01 AG037593-01A1).

The authors thank Vanitha Janakiraman Mohta, MD, Senior Staff Physician, Obstetrics and Gynecology, Kaiser Permanente Walnut Creek, for her critical review of the manuscript.

Financial Disclosure The authors did not report any potential conflicts of interest.

© 2013 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.