LDH and ApoA1 levels in patients with severe pneumonia who had acute exacerbation of chronic obstructive pulmonary disease or MODS combined during hospitalization were higher than those in patients with severe pneumonia without acute exacerbation of chronic obstructive pulmonary disease or MODS, and the difference was statistically significant (P<0.05). Here, APOA1 is linked to susceptibility to pneumonia measurement.