Table 3.

90-day all-cause readmission and complications following hospitalisation with pneumonia in patients with and without ankylosing spondylitis (AS)

	1997–2017*		1997–2006		2007–2017*
	AS	Non-AS	AS	Non-AS	AS	Non-AS
90-day readmission, n (%)	230 (27.3)	98.445 (25.4)	78 (28.5)	39.106 (24.2)	152 (26.8)	59.238 (26.4)
Crude 90-day HR	1.08 (0.95 to 1.22)	1.00 (ref)	1.14 (0.91 to 1.43)	1.00 (ref)	0.96 (0.82 to 1.12)	1.00 (ref)
Adjusted 90-day HR†	1.12 (0.98 to 1.27)	1.00 (ref)	1.15 (0.92 to 1.44)	1.00 (ref)	1.05 (0.89 to 1.23)	1.00 (ref)
Pulmonary complication, n (%)	16 (1.9)	7.610 (2.0)	8 (2.9)	2.650 (1.6)	8 (1.4)	4.941 (2.2)
Crude HR complication	0.99 (0.61 to 1.62)	1.00 (ref)	1.74 (0.87 to 3.48)	1.00 (ref)	0.60 (0.30 to 1.21)	1.00 (ref)
Adjusted HR complication	0.97 (0.59 to 1.58)	1.00 (ref)	1.63 (0.82 to 3.27)	1.00 (ref)	0.62 (0.31 to 1.23)	1.00 (ref)

HRs with 95% CIs were calculated using a Cox proportional-hazards model.

*Until 31 July 2017.

†Adjusted for sex, age and level of comorbidity (Charlson Index).