Effect of inflammatory bowel disease treatments on patients with diabetes mellitus

Abstract

As medical care progresses and the number of patients with chronic conditions increases there is the inevitable challenge of managing patients with multiple co-morbidities. Inflammatory bowel disease (IBD) is an umbrella term for are inflammatory conditions affecting the gastrointestinal tract, the two most common forms being Ulcerative Colitis and Crohn’s disease. These diseases, usually diagnosed in young adults, exhibit a relapsing and remitting course and usually require long-term treatment. IBD can be treated with a number of topical and systemic treatments. We conducted a review of the current published evidence for the effects these medications can have on diabetes mellitus (DM) and glycaemic control. Searches were conducted on medline and embase with a timeframe from 1947 (the date from which studies on embase are recorded) to November 2020. Suitable publications were selected and reviewed. Current evidence of the impact of aminosalicylates, corticosteroids, thiopurines, and biologic agents was reviewed. Though there was limited evidence for certain agents, IBD medications have been shown to have an effect of DM and these effects should be considered in managing patients with dual pathologies. The effects of steroids on blood sugar control is well documented, but consideration of other agents is also important. In patients requiring steroids for Ulcerative Colitis, locally acting steroid agents delivered rectally may be preferred to minimise side effects in those with distal bowel Ulcerative Colitis. A switch to other agents should be considered as soon as possible in people with diabetes to limit the impact on glycaemic control. 5-aminosalicylates appear to play a role in the reduction of hemoglobin A1c (HbA1c), although the literature suggests these may be falsely low readings. Consequently, monitoring of people with diabetes on these agents may require daily monitoring of capillary blood sugars rather than relying simply on HbA1c; for example fructosamine performed 3-6 monthly, although this risks missing the rise in readings. There is only limited evidence of the effects of thiopurines on diabetes and further investigation is needed into the possible relationship between them. However, given the current available evidence it may be preferable to commence patients with diabetes on thiopurines as soon as possible, whilst also monitoring for side effects such as pancreatitis. There appears to be more evidence supporting a link between tumor necrosis factor-α inhibitors and DM. Both infliximab and adalimumab have evidence suggesting that both can cause reduced blood sugar levels. Further studies on the effects of the various biological agents mentioned are required alongside any novel biologic therapy and the impact of dual biologic therapy in the future.

Keywords: Inflammatory bowel disease; Diabetes mellitus; Crohn's disease; Ulcerative colitis; Anti-tumor necrosis factor-α; Corticosteroids

Core Tip: For patients with diabetes mellitus and inflammatory bowel disease, medication may influence glycaemic control. Furthermore, immunosuppressive therapy may modify the likelihood of other autoimmune conditions. Further studies on the effects of the various biological agents mentioned are required alongside any novel biologic therapy and the impact of dual biologic therapy in the future.