Table 3.

Incidence rate ratio and hazard ratio of Parkinson's disease and ankylosing spondylitis cohort to non-ankylosing spondylitis cohort

Variables	Ankylosing spondylitis						Crude HR (95%CI)	Adjusted HR† (95%CI)
	No (N = 25,760)			Yes (N = 6440)
	event	Person years	rate	event	Person years	rate
Sex
Male	111	82,421	1.35	52	20,957	2.48	1.85 (1.33, 2.57)***	1.66 (1.19, 2.32)**
Female	99	88,437	1.12	50	22,295	2.24	2.01 (1.43, 2.82)***	1.85 (1.31, 2.62)***
Age, years
≤ 49	11	100,196	0.11	14	25,575	0.55	4.99 (2.26, 11.0)***	4.70 (2.10, 10.5)***
50–64	50	44,307	1.13	21	11,120	0.89	1.68 (1.01, 2.80)*	1.32 (0.78, 2.21)
≥ 65	149	26,356	5.65	67	6557	10.2	1.80 (1.35, 2.40)***	1.69 (1.26,2.26)***
Comorbidity‡
No	46	114,349	0.40	22	24,374	0.90	2.25 (1.35, 3.74)**	2.71 (1.63, 4.50)***
Yes	164	56,509	2.90	80	18,878	4.24	1.47 (1.12, 1.92)**	1.61 (1.23, 2.10)***

Rate per 1000 person-year; Crude HR, relative hazard ratio

^†Model was adjusted for age and comorbidities of diabetes, hypertension, hyperlipidemia, stroke, depression, coronary artery disease, head injury, and chronic kidney disease and medication of NSAIDs

^‡Patients with any one of the comorbidities (diabetes, hypertension, hyperlipidemia, stroke, depression, coronary artery disease, head injury, chronic kidney disease and epilepsy) were classified as the comorbidity group

^*p < 0.05, **p < 0.01, ***p < 0.001