Appendectomy history is associated with severe disease and colchicine resistance in adult familial Mediterranean fever patients

Background/aim: Peritonitis attacks of Familial Mediterranean Fever (FMF) usually requires emergency medical admissions and it's hard to distinguish a typical abdominal attack from surgical causes of acute abdomen. Therefore, history of abdominal surgery, particularly appendectomy, is very common in patients with FMF. However, history of appendectomy might also give some clues about the course of FMF in the adulthood. This study was to determine whether the history of appendectomy help to anticipate disease course of FMF in the adulthood. Materials and methods: All patients recruited from FMF in Central Anatolia (FiCA) cohort, comprising 971 adult subjects. All patients fulfilled the Tel Hashomer criteria. Demographic data, FMF disease characteristics, co-morbid conditions, past medical history, surgical history and disease complications were meticulously questioned and laboratory features and genotype data (if available) were recruited from patient files. Results: Appendectomy history was evident in 240 (24.7%) subjects. Disease onset was earlier and peritonitis is strikingly more prevalent (97.1% vs. 89.6%, p < 0.001) in appendectomized patients. These patients had reported almost two fold more frequent attacks in the last year compared to appendix intact patients (median 3.5 vs. 2 attacks, p = 0.001) without a difference in frequency of musculoskeletal and skin attacks. Severe disease was more common (10% vs. 5.9%, p = 0.038) due to involvement of more attack sites throughout the life and more frequent attacks. Appendectomy patients had used higher daily doses of colchicine to control disease (1.43 ± 0.6 mg vs. 1.27 ± 0.52 mg, p = 0.002) but colchicine resistance was also more common in these patients, 15% vs. 6.7% respectively, p < 0.001. Conclusion: Appendectomy history is common in FMF patients and associated with frequent serositis attacks in adulthood. These patients require higher colchicine doses with a lower rate of response and more need for Interleukin-1 antagonist therapies.