Risk of acute pancreatitis among people with severe mental illness

Severe Mental Illness (SMI) encompasses schizophrenia, schizoaffective disorder, and bipolar affective disorder. SMI is associated with increased physical morbidity and mortality. Acute pancreatitis is the leading cause of gastroenterological hospitalisation. This study investigates the relationship between SMI and acute pancreatitis and determines the risk factors for development of pancreatitis.

The first study phase was a retrospective cohort analysis. Acute admissions for pancreatitis were determined for people with an SMI diagnosis between January 2007 and March 2016 from a secondary care mental health register. Standardised admission ratio (SAR) for acute pancreatitis was determined for SMI patients. The second phase was a case-control study to compare exposures between SMI subjects admitted for acute pancreatitis ("cases") and the age-, gender-, and diagnosis-matched SMI subjects without admission for acute pancreatitis ("controls"), with a ratio of 1:4. Univariate and multivariate conditional logistic regression estimated the effect of exposures including diagnosis of alcohol use disorder (AUD).

A total of 22,337 SMI subjects were identified during the observation period. The SAR for acute pancreatitis was significant (2•33 (95% Ci: 1•97, 2•74; n = 148)). In the nested case-control study, SMI patients with co-morbid AUD elevated the risk of acute pancreatitis dramatically with an adjusted odds ratio 16•10 (5•92, 43•79).

Diagnosis of co-morbid AUD may be under represented in population CONCLUSIONS: SMI is associated with a significantly elevated risk of acute pancreatitis. Co-morbid AUD is a risk factor in development of pancreatitis in this group.