GSTM1 and chronic obstructive pulmonary disease: Compared to T1, there were a significant differences in age, sex, ethnicity, Hb, PC, BUN, Mg, AF, CHF, ACS, COPD, cancer, or hypertension in T2 and T3 (P < 0.05). Additionally, in comparison to T1, hospital and ICU mortality rates were significantly reduced, and the length of stay in hospitals in T2 and T3 was also significantly shorter (P < 0.05).