Acute Appendicitis in the Adult Population: Modelled Decision Analysis Supports a Conservative Approach

Acute appendicitis represents the commonest cause of acute intra-abdominal pathology. Appendectomy and antibiotics are the mainstay of therapy for appendicitis. Evidence is emerging that antibiotics alone may adequately treat most cases of appendicitis. Decision analysis is a quantitative method of examining alternate treatment strategies. This study describes a modelled decision analysis comparing operative and conservative management of appendicitis. The base case patient is a healthy, 23-year-old male presenting with migratory pain to the right iliac fossa (RIF) and elevated inflammatory markers. A decision tree was constructed comparing operative and conservative treatment. Rates of complications, failure of conservative therapy, recurrence and utilities were calculated via a systematic literature review. Variables were tested for sensitivity. Overall, conservative management gives a significantly better outcome (51.51 vs 49.87 QALYs). Three variables proved sensitive. Once operative complication rates are lower than 11.5 %, surgical treatment becomes the optimal strategy. If rates of failure of conservative management exceed 12.9 %, surgery becomes optimal. If the utility assigned to a post-operative complication exceeds 0.44, surgery becomes optimal. This decision analysis supports a conservative strategy, albeit with caveats. If operative complications are low or rates of failure of conservative management remain high, surgery is the preferable strategy.