Subgroup analysis for the impact of short MPT on late-onset pneumonia. The odds ratio in each subgroup was adjusted for the effects of the preoperative variables (age, gender, BMI, ASA-PS, Brinkman index, RSST, VC % predicted, FEV1.0% predicted, albumin level, diabetes mellitus, and cardiovascular disease). Red squares represent OR; horizontal blue lines illustrate 95% CI.