Watchful Waiting Versus Interval Appendectomy for Patients Who Recovered from Acute Appendicitis with Tumor Formation: A Cost-effectiveness Analysis

Background: Interval appendectomy after conservative treatment of appendicitis with tumor formation remains controversial. The purpose of this study was to evaluate the efficacy of interval appendectomy based on a costeffectiveness analysis. Methods: This was a retrospective study including appendicitis patients with tumor formation who received conservative treatment at first admission to Taipei Veterans General Hospital between January 1998 and December 2003. Demographic data, rate of recurrent appendicitis, and medical costs were analyzed. Results: Of the 165 patients, 1 died after an acute myocardial infarction. The rate of recurrence of appendicitis after conservative treatment was 25.5%. The median cost of follow-up after conservative treatment was NT$24,344. The median cost of interval appendectomy was NT$47,746. The median cost of appendectomy after recurrent appendicitis was NT$62,135. Routine interval appendectomy in all 164 patients would have cost NT$7,830,344. The follow-up protocol with appendectomy after recurrence cost NT$5,655,220. An additional NT$2,175,124 (38%) would have been needed for routine interval appendectomy compared with the follow-up policy, an extra NT$13,263 per person. Conclusion: Routine interval appendectomy would increase the cost per patient by 38% compared with follow-up and appendectomy after recurrence. Routine interval appendectomy is not a cost-effective intervention. [J Chin Med Assoc 2005;68(9):431–434]