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Saturday, September 14, 2013

Trailers (59): Imaging for appendicitis during pregnancy

Kastenberg et al. Cost-effectiveness of preoperative imaging for appendicitis after indeterminate ultrasound in the second or third trimester of pregnancy

Why should you read about this topic?

Appendicitis is frequently encountered in pregnant women with potentially catastrophic consequences.  Accurate and cost-effective means of diagnosis prior to surgery is key to a successful outcome for mother and baby.

What were the authors trying to do?

Analyze the cost-effectiveness of MRI, CT, or diagnostic laparoscopy for diagnosing appendicitis during pregnancy in the setting of clinical suspicion and an indeterminate ultrasound

Who participated and in what setting?

Computer-based model of 25-year-old women with suspected appendicitis in the second or third trimester

What was the study design?

Decision analysis

What were the main outcome measures?

Incremental cost per quality adjusted life year (QALY)

What were the results?

MRI is the most cost-effective strategy, costing $6,767 per QALY.  Outcomes are driven by rates of prematurity and fetal loss from the surgery itself, making MRI or CT cost-effective over laparoscopy unless the negative appendectomy rate is less than 1%.

What is the most interesting image in the paper?

Figure 1

What were the study strengths and weaknesses?

Strengths: appropriate sensitivity analyses.      Weaknesses: first trimester cases excluded; base case analysis mostly employed estimates from retrospective studies and expert opinion.

What does the study contribute for your practice?

If the ultrasound is unclear about whether your pregnant patient has appendicitis, MRI is the best next step.