Table 4.

Incidence rate ratio (IRR) for 90-day mortality after surgery for hip fracture

Variable		IRR (95% CI)	P value
β-blocker therapy
	No	Ref
	Yes	0.82 (0.68 to 0.98)	0.03
Age		1.05 (1.04 to 1.07)	<0.001
Sex
	Female	Ref
	Male	1.49 (1.23 to 1.80)	<0.001
Charlson Comorbidity Index
	≤4	Ref
	5–6	2.03 (1.41 to 2.94)	<0.001
	≥7	2.87 (1.97 to 4.17)	<0.001
ASA classification
	1	Ref
	2	1.87 (0.79 to 4.46)	0.15
	3	2.92 (1.23 to 6.92)	0.01
	4	5.24 (2.16 to 12.73)	<0.001
Fracture type
	Non-displaced cervical (Garden 1–2)	Ref
	Displaced cervical (Garden 3–4)	1.07 (0.73 to 1.57)	0.72
	Basicervical	1.45 (0.80 to 2.63)	0.22
	Pertrochanteric (two fragments)	1.68 (0.98 to 2.86)	0.05
	Pertrochanteric (multiple fragments)	1.37 (0.79 to 2.38)	0.26
	Subtrochanteric	1.13 (0.58 to 2.21)	0.72
Type of surgery
	Screws or pins	Ref
	Screws or pins with side plate	0.87 (0.54 to 1.40)	0.56
	Intramedullary rod	0.84 (0.50 to 1.43)	0.52
	Hemiarthroplasty	0.95 (0.66 to 1.35)	0.75
	Total hip replacement	0.52 (0.23 to 1.20)	0.12

Poisson regression model with robust standard errors, multiple imputation was used for missing values. Model adjusted for age, sex, Charlson Comorbidity Index, ASA classification, fracture type and type of surgery. Multiple imputation method for missing ASA values.

ASA, American Society of Anesthesiologists; CI, Confidence interval.