Table 2.

Mediation-style decomposition of frailty-associated healthcare outcomes.

Outcome	Mediator	Total effect (95% CI)	ADE (95% CI)	ACME (95% CI)	% Mediated	P
High inpatient costs	comorbidity index	0.079 (0.045–0.112)	0.057 (0.023–0.091)	0.023 (0.015–0.031)	28.6	< 0.001
Length of stay, log-transformed	complications	0.085 (0.057–0.114)	0.082 (0.054–0.111)	0.003 (−0.004–0.011)	3.8	0.368

ADE, average direct effect; ACME, average mediation effect. Estimates are from mediation-style decomposition models. Because the comorbidity index was measured at or around admission, the comorbidity pathway should be interpreted as co-occurring comorbidity burden rather than definitive causal mediation. Postoperative complications were analyzed as a binary composite variable.