Table 5.

Proportion of mediation of smoking to mortality association explained by each complication in unadjusted and adjusted models

Outcome	Mediator	Proportion mediation unadjusted for covariates (%)	Proportion mediation adjusted for covariates (%)
6 months mortality	Surgical site infection	22.2	2.0
	Cardiovascular complications	12.2	3.8
	Pulmonary complications	88.9	21.6
	Composite outcome	86.4	15.7
1 year mortality	Surgical site infection	12.6	1.7
	Cardiovascular complications	6.5	3.0
	Pulmonary complications	42.7	16.2
	Composite outcome	40.8	11.3

Because the proportion mediated is ratio statistic, its estimated value is sensitive to variation in point estimates of the regression coefficients from which it is derived; it should therefore be interpreted with caution. Coefficient values (magnitude and significance) should be the main proponent in assessing mediation.