Glucose intolerance and diabetes mellitus in ulcerative colitis: pathogenetic and therapeutic implications

Diabetes mellitus is one of the most frequent co-morbidities of ulcerative colitis patients. The epidemiological association of these diseases suggested a genetic sharing and has challenged gene identification. Diabetes co-morbidity in ulcerative colitis has also relevant clinical and therapeutic implications, with potential clinical impact on the follow up and outcome of patients. These diseases share specific complications, such as neuropathy, hepatic steatosis, osteoporosis and venous thrombosis. It is still unknown whether the coexistence of these diseases may increase their occurrence. Diabetes and hyperglycaemia represent relevant risk factors for postoperative complications and pouch failure in ulcerative colitis. Medical treatment of ulcerative colitis in patients with diabetes mellitus may be particularly challenging. Corticosteroids are the treatment of choice of active ulcerative colitis. Their use may be associated with the onset of glucose intolerance and diabetes, with difficult control of glucose levels and with complications in diabetic patients. Epidemiologic and genetic evidences about diabetes co-morbidity in ulcerative colitis patients and shared complications and treatment of patients with these diseases have been discussed in the present review.