Endoscopic sphincterotomy (ES) may not alter the natural history of idiopathic recurrent acute pancreatitis (IRAP).

Background: The role of endoscopic sphincterotomy (ES) in idiopathic recurrent acute pancreatitis (IRAP) is unclear. We hypothesized that ES will alter the natural history of IRAP.

Methods: We retrospectively studied the course of 50 IRAP patients from the NAPS2 study from UPMC based on whether they underwent ES or were managed medically. Data included age at first AP, rate of attacks, and history of severe AP. Primary outcomes were any subsequent AP and rate of attacks; secondary outcome was chronic pancreatitis (CP) diagnosis during follow-up. Similar data was abstracted for alcoholic RAP.

Results: When compared with medically managed IRAP patients (n = 24, 48%), those who underwent ES (n = 26, 52%) had similar rate of attacks/year (median 1.54 vs. 1.41, p = 0.63), but significantly more attacks (median 3 vs. 2, p = 0.04) at baseline. During follow-up (median 7 years), rate of attacks/year decreased significantly, and were similar in both groups (median 0.16 vs. 0, p = ns). Predictors for rate of attacks during follow-up were sex (ratio 0.54 in females, p = 0.045) and rate of attacks at baseline (ratio for doubling 1.2, p = 0.025), but not ES. Alcoholic RAP patients had lower rate of attacks at baseline, but higher risk of subsequent AP (80 vs. 46%, p = 0.021) and rate of attacks/year (median 0.25 vs. 0, p = 0.016) during follow-up. Progression to CP occurred in IRAP and ES, medically managed IRAP, and alcoholic RAP in 27%, 8% and 27% respectively (p = ns).

Conclusions: ES, chosen in patients with higher burden of attacks, does not seem to impact the natural history of IRAP.