In total 2161 patients (obesity class I (10.2%), class II (40.3%), class III (49.5%)) were matched to 2161 non-surgical patients (mean age 51.1 ± 9.29 vs 51.5 ± 8.92 years, 64.8% vs. 64.4% women, with mean number of diabetes drugs of 2.5 ± 0.89 vs 2.6 ± 0.87, a mean duration of diabetes of 6.0 ± 4.15 vs 6.0 ± 4.51 years with 44.2% vs. 42.8% being treated with insulin at baseline). This evidence concerns the gene INS and diabetes mellitus.