Table 4.

Difference in absolute risk of in-hospital mortality in hip fracture patients after IPW, stratified by cardiac risk.

Level of cardiac risk	Surgery ≤24 h (%)	Surgery >24 h (%)	ARD (95% CI)	P-value
RCRI 0	0.8	1.1	0.30 (0.24–0.37)	<0.001
RCRI 1	1.6	1.9	0.35 (0.22–0.49)	<0.001
RCRI 2	3.5	3.9	0.42 (0.04–0.81)	0.030
RCRI 3	6.3	8.0	1.69 (0.49–2.89)	0.006
RCRI ≥4	7.7	12.3	4.65 (0.90–8.40)	0.015

Using IPW, all strata were balanced in regard to age, sex, race, highest AIS in each region, type of fracture, type of surgery, and comorbidities.

IPW, inverse probability weighting; ARD, absolute risk difference; CI, confidence interval; RCRI, revised cardiac risk index; AIS, abbreviated injury scale.