**6. Factors predicting the outcome of surgery in diabetic patients**

Most obese type 2 diabetes subjects who underwent bariatric surgery show an important improvement of metabolic features but not every patient has diabetes remission after surgery, suggesting that some clinical characteristics could predict which patient is best suitable for a particular metabolic surgery procedure. Furthermore it is important to identify patients who will not respond to metabolic surgery, so that these patients not to be exposed to an unneces‐ sary surgical procedure that could be without clear benefits. Clinical studies showed that the main factors that contribute to the control of diabetes and eventually to the remission of the diseases are as follows:


characterized by continuous decrease of beta cell function. Absence of insulin treatment was a predictive factor for remission of diabetes after bariatric surgery. [68, 71] The insulin use was associated with lower remission rates compared with oral medication (13.5 versus 53.8%). [72]


The combination of these factors has an increased power in prediction of the outcomes. If a score of 1 is assigned to duration of diabetes <4years, percentage weight loss at 1 year >25%, and C-peptide ≥2.9ng/ml at baseline, a cumulative score of 2 or 3 was associated with a remission rate of 92%, and a score of 0 or 1 was associated with a remission rate of 27%. [69]

In a retrospective cohort study on 690 patients was developed a score, DiaRem, to predict probability of diabetes remission within five years after Roux-en-Y gastric bypass surgery. Four preoperative clinical variables were identifying of importance in this score: insulin use (no use 0, use of insulin 10 points), age (<40 years 0, 40-49 years 1 point, 50-59 years 2 points, >60 years 3 points), glycated hemoglobin (<6.5% 0, 6.5-6.9% 2 points, 7-8.9% 4 points, >9% 6 points), and type of antidiabetic drugs (no sulfonylureas or insulin-sensitising agents other than metformin 0, sulfonylureas and insulin-sensitising agents other than metformin 3 points). [68] The DiaRem score ranges from 0 to 22. [68] The study showed that 88% of patients who scored 0-2, 64% of those who scored 3-7, 23% of those who scored 8-12, 11% of those who scored 13-17, and 2% of those who scored 18-22 achieved remission (partial or complete) according ADA definition. [68]
