Background : Symptomatic cholelithiasis (“biliary colic” (BC)) is often managed with elective laparoscopic cholecystectomy, with wait times up to 1-year prior surgery. This holds a risk of progression to complicated gallstone disease including acute biliary pancreatitis (ABP). ABP can cause significant morbidity and incurs additional costs for the healthcare system. There is currently no systematic review assessing the risk factors for patients with BC to progress to ABP, such a review was therefore the objective of this study

Methods : A systematic review of the PubMed database, the Cochrane Library and Google Scholar was performed. After identification or relevant articles, predetermined data was extracted and independently analysed by two authors. Results were reported as per PRISMA guidelines. Pooled effect size was calculated using a common effects model on factors with sufficient data.

Results : 11 studies were included describing a total of 543 ABP patients and 2358 BC patients. ABP patients had smaller gallstones than patients with biliary colic (MD -5.20 p ≤0.01). Bubble plot distribution of gallstone size within the ABP group results in an inverse sigmoidal curve shape, demonstrating an increased risk of ABP as gallstone size decreases with a significant risk observed with stones less than 5mm in diameter. Total gallstone number did not differ between groups.

Conclusions : This systematic review demonstrates smaller gallstones are associated with ABP and this associated strengthens as gallstone size reduces. Clinicians should utilise this information when assessing patients with BC and consider expediting surgery in patients with smaller gallstones to reduce to risk of progression to ABP.