Table 3. Effect of pneumonia on all-cause 90-day mortality according to the age group in elderly hip fracture patients.

Age group, yr	Non-pneumonia group (reference)	Pneumonia group
		aRR	95% CI		P value
< 70	1.00	5.75	2.89	11.43	< 0.001
70–79	1.00	5.14	4.08	6.46	< 0.001
80–89	1.00	3.29	2.81	3.86	< 0.001
≥ 90	1.00	2.02	1.52	2.69	< 0.001

aRR = adjusted risk ratio, CI = confidence interval.

P for interaction < 0.001.