Natural course of pain in chronic pancreatitis is independent of disease duration.

Objectives: Pain burn-out during the course of chronic pancreatitis (CP), proposed in the 1980s, remains controversial, and has clinical implications. We aimed to describe the natural course of pain in a well-characterized cohort.

Methods: We constructed the clinical course of 279 C P patients enrolled from 2000 to 2014 in the North American Pancreatitis Studies from UPMC by retrospectively reviewing their medical records (median observation period, 12.4 years). We assessed abdominal pain at different time points, characterized pain pattern (Type A [short-lived pain episodes] or B [persistent pain and/or clusters of recurrent severe pain]) and recorded information on relevant covariates.

Results: Pain at any time, at the end of follow-up, Type A pain pattern or B pain pattern was reported by 89.6%, 46.6%, 34% and 66% patients, respectively. In multivariable analyses, disease duration (time from first diagnosis of pancreatitis to end of observation) did not associate with pain - at last clinical contact (OR, 1.0, 95% CI 0.96-1.03), at NAPS2 enrollment (OR 1.02, 95% CI 0.96-1.07) or Type B pain pattern (OR 1.01, 95% CI 0.97-1.04). Patients needing endoscopic or surgical therapy (97.8 vs. 75.2%, p < 0.001) and those with alcohol etiology (94.7 vs. 84.9%, p = 0.007) had a higher prevalence of pain. In multivariable analyses, invasive therapy associated with Type B pain and pain at last clinical contact.

Conclusions: Only a subset of CP patients achieve durable pain relief. There is urgent need to develop new strategies to evaluate and manage pain, and to identify predictors of response to pain therapies for CP.