INS and diabetes mellitus: Patients operated on in GFH with diabetes had a significantly increased risk of requiring more than one oral hypoglycaemic agent (OR = 2.55 (CI95% 1.45–4.48), P = 0.001) and insulin (OR = 3.24 (CI95% 1.85–5.66), P < 0.001) compared to PFH (Fig. 2).