Table 2. Cox Proportional Hazards Models.

Model	HR (95% CI)a
Model 1: MM levels
Undergoing surgery	0.71 (0.56-0.90)
Age	1.05 (1.03-1.06)
Sex
Female	0.53 (0.43-0.66)
Male	1 [Reference]
MM level
0 or 1	1 [Reference]
2 (any 2 domains)	1.25 (0.90-1.75)
3	2.06 (1.48-2.87)
Model 2: MM domain combinations
Undergoing surgery	0.71 (0.56-0.90)
Age	1.05 (1.03-1.06)
Sex
Female	0.53 (0.43-0.65)
Male	1 [Reference]
Domain combination
No MM (MM0 or 1)	1 [Reference]
MM2: GS and CC	1.15 (0.82-1.62)
MM2: FL and CC	1.83 (1.03-3.23)
MM2: FL and GS	2.91 (1.37-6.18)
MM3: FL, GS, and CC	2.08 (1.49-2.89)

Abbreviations: CC, chronic conditions; FL, functional limitations; GS, geriatric syndromes; HR, hazard ratio; MM, multimorbidity.

^a Hazard ratios and 95% CIs from a Cox proportional hazards model to examine the association between multimorbidity and mortality, controlling for sex, procedure, and multimorbidity.