Length of stay per procedure type was assessed against the following risk factors: ASA grade, estimated glomerular filtration rate (eGFR), low Hb (< 13.8 g/dL in males; < 12.4 g/dL in females), obesity (defined as BMI ≥ 30 kg/m2) and presence of diabetes mellitus. The gene discussed is GSTM1; the disease is diabetes mellitus.