Background/ObjectiveAcute appendicitis is predominantly managed with appendectomy, but can be treated non-operatively, leading to recurrence risk. Non-operative management has been more common since the COVID-19 pandemic affected the feasibility of performing surgery. This case-control study analyzed non-operatively managed patients in order to identify clinical and radiological factors associated with recurrence risk. MethodsOver 12 months, 48 adults with CT-proven acute appendicitis managed non-operatively were identified, and followed up for at least 6 further months to assess them for recurrence (reattendance to hospital more than 14 days after discharge and after symptom resolution, requiring treatment for appendicitis). Clinical and CT data were collected and a Cox regression survival analysis was performed to produce hazards ratios. ResultsOf the 48 patients, 12 (25%) experienced a recurrence up until the end of the follow-up period, 8 of whom were then treated operatively. On the univariate analysis, greater recurrence risk was observed in patients with diabetes mellitus, higher pulse rate (on admission and maximum value during admission), lower white cell count and neutrophils and appendiceal wall thinning on CT. On the multivariate analysis, diabetes mellitus (hazards ratio=7.72, p=0.021) and higher pulse rate (hazards ratio=1.08, p=0.018) were associated with statistically significant greater recurrence risk. ConclusionsDiabetes mellitus and higher pulse rate on admission are associated with greater recurrence risk of acute appendicitis managed non-operatively. No CT findings were associated with greater risk. Clinicians should therefore consider diabetes mellitus and pulse rate when making decisions on appendicitis management, during the COVID-19 pandemic and beyond.

Background/Objective: Acute appendicitis (AA) is predominantly managed with appendectomy, but can be treated non-operatively, leading to a high risk of recurrence. Non-operative management has been more common since the COVID-19 pandemic affected the feasibility of performing surgery. This case-control study analyzed non-operatively managed patients in order to identify clinical and radiological factors associated with recurrence risk. Methods: Over 12 months, 48 adults with CT-proven AA managed non-operatively were identified, and followed up for at least six further months to assess them for recurrence (readmission to hospital more than 14 days after discharge and after symptom resolution, requiring treatment for appendicitis). Clinical and CT data were collected and a Cox regression survival analysis was performed to produce hazards ratios (HRs).Results: Of the 48 patients, 12 (25%) experienced a recurrence up until the end of the follow-up period, eight of whom were then treated operatively, and four treated non-operatively. On the univariate analysis, greater recurrence risk was observed in patients with diabetes mellitus, higher heart rate (on admission and maximum value during admission), lower white cell count and neutrophils and appendiceal wall thinning on CT. On the multivariate analysis, diabetes mellitus (HR=7.72, p=0.021) and higher heart rate (HR=1.08, p=0.018) were associated with statistically significant greater recurrence risk. Conclusions: Diabetes mellitus and higher heart rate on admission are associated with greater recurrence risk of AA managed non-operatively. No CT findings were associated with statistically significant greater risk. Clinicians should, therefore, consider DM and heart rate when making decisions on appendicitis management, especially during the COVID-19 pandemic but also beyond it.