Statistical analysis
REGRESSION
A propensity score matching (PSM) method was applied to minimize bias associated with confounding variables. Age (> 70 years), BMI score, ASA score (Classes 1, 2, and ≥ 3), preoperative comorbidities, duration of anesthesia, duration of surgery, intraoperative remifentanil dose, muscle relaxant dose, and type of surgery were matched as covariates. A 1:1 ratio matching was performed based on the propensity score with a standard caliper width of 0.2.After confirming balance in the matched cohort with generalized linear models with a logarithmic link function, Wilcoxon signed-rank test was applied for propensity-matched patients; results of dichotomous variables were expressed as relative risk (RR) and 95% confidence intervals (95% CI). Mann-Whitney U test was used for continuous outcomes in all patients. Univariate and multiple linear regression analyses were applied after PSM to evaluate the difference between the groups of length of hospital stay, time-to-first-defecation, postoperative ambulation time, and length of PACU stay. 