GSTM1 and chronic obstructive pulmonary disease: Univariate analysis showed that significantly elevated risk of DVT were found in patients with longer time from injury to admission, high energy injury, lower Hb value, higher BMI, diabetes, chronic obstructive pulmonary disease (COPD), atrial fibrillation, dementia, varicose veins, higher age-adjusted CCI, higher ASA class and A3 type intertrochanteric fractures (P < 0.05).