Table 2. Association of Memorial Sloan Kettering–Frailty Index Score With Surgical Outcomes^a.

Variable	Estimate (95% CI)b	P Value	P Value for Heterogeneityc
Length of stay	0.58 (0.22-0.95)	.002	.37
Readmission within 30 d of surgery	0.98 (0.82-1.17)	.84	.26
ICU admission within 30 d of surgery	1.28 (1.04-1.58)	.02	.98
Major complicationsd	1.04 (0.84-1.29)	.70	.77d

Abbreviation: ICU, intensive care unit.

^aAdjusted for age at surgery, operating room duration, American Society of Anesthesiologists score, preoperative albumin level (included in the model as a nonlinear term), and the presence of polycomorbid conditions.

^bEstimate corresponds to β (linear regression model for the outcome of length of stay) and odds ratio (logistic regression model for the outcomes of readmission and ICU admission) for a 1-point change on the frailty index. For Cox regression model for overall survival, P = .005.

^cThe heterogeneity P value tests the null hypothesis that the association of the outcome with Memorial Sloan Kettering–Frailty Index score does not differ on the basis of type of surgical procedure. Statistical significance set at P < .05.

^dThis analysis excluded 72 patients undergoing neurosurgery procedures, as only 1 patient had a major complication.