Background: Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis that may lead to endocrine and exocrine insufficiency if left untreated. AIP clinically responds to glucocorticoids (GCs) therapy, but multiple GCs courses are often required to maintain remission with potential detrimental effects on glycaemic control. To date, data on pancreatic function in AIP are scanty and heterogeneous.

Objectives: We aimed to assess the rate of endocrine and of exocrine insufficiency at diagnosis and at follow up in patients with AIP as well as the impact of GC therapy on pancreatic function in the long term.

Methods: The MEDLINE, SCOPUS, and EMBASE databases were searched from inception to August 2021 to identify studies reporting data on endocrine and exocrine insufficiency in patients with type 1or type 2 AIP. Studies involving ≥ 3 patients were selected. In case of duplicated studies, the most recent or the one with the largest sample were included. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled events were calculated using a random-effect model and expressed in terms of pooled prevalence rates.

Results: A total of 6522 AIP patients and sixty-two studies were included in the analysis. The pooled estimate rate for the overall prevalence of diabetes in AIP at baseline (combined type 1 and type 2 AIP) was 36.9% (95% CI 31.9-41.9, I ² 96.1%). The pooled estimate for the prevalence of diabetes was 44.3% (95%CI 39.1-49.4, I ² 91.9%) in type 1 AIP and 11.3% (95%CI 6.1-16.6, I ² 42.5%) in type 2 AIP (p < 0.01), respectively. The pooled prevalence rate of exocrine insufficiency was 45.2% (95%CI 32.9-57.4; I ² 97.4%). The pooled estimate rate of diabetes at follow-up was 44.2% (95%CI 26.1-62.4) in studies where GCs were given to 100% of patients and 41.8% (95%CI 30.6-52.9) in studies where GCs were given to less than 100% of patients. The pooled prevalence of pancreatic exocrine insufficiency was 36.2% (95%CI 20.4-52.0, I ² 96.4%).

Conclusion: A large proportion of patients with AIP displays concomitant exocrine and endocrine insufficiency at the time of diagnosis. The incidence of diabetes at the longest available follow up tends to increase in patients treated with GCs. Further long-term studies are warranted to assess the impact of GCs and immunosuppressive treatments on glycaemic control and on exocrine pancreatic function.

REFERENCES:

[1]Löhr JM, Beuers U, Vujasinovic M, et al. European Guideline on IgG4-related digestive disease - UEG and SGF evidence-based recommendations. United European Gastroenterol J. 2020;8:637-666.

[2]Lanzillotta M, Vinge-Holmquist O, Overbeek KA, et al.PrescrAIP: A Pan-European Study on Current Treatment Regimens of Auto-Immune Pancreatitis. Front Med. 2020 Aug 5;7:408.

Disclosure of Interests: None declared