Table 4: Postoperative length of stay by age groups.

Age groups	N	Median (IQR)	Mean (SD)
Age (65-75)	3811	4 (3-5)	4.33 (7.64)
Age (76-89)	10467	4 (3-6)	4.59 (8.87)

A nonparametric Mann-Whitney U Test (because of the skewed distributions) revealed that difference in postoperative length of stay between the two age groups is significant (P = 0.001). However, after adjusting for Gender, BMI, Functional status and ASA class, general linear model showed no significance (P = 0.63).