NPPB and delirium: Conversely, low PMA was significantly associated with the elevated risk of delayed acquisition of independent walking even in the all adjusted models including age, type of operation, GNRI, eGFR, BNP, delirium, duration requiring mechanical ventilator, and physical fitness [model 1: SPPB (OR, 1.14; 95% CI: 1.03–1.25), model 2: GS/BMI (OR, 1.13; 95% CI: 1.03–1.25), and model 3: 6MWD (OR, 1.14; 95% CI: 1.03–1.25)].