Table 2.

Cox model measured HRs and 95% CIs of hearing loss associated with RA and covariates

Variable	Event (n)	Person-years	Incidence density†	HR (95% CI)
				Univariate	Multivariate‡
RA
No	927	572 031	1.62	Ref	Ref
Yes	429	139 085	3.08	1.90 (1.70 to 2.13)***	1.91 (1.70 to 2.14) ***
Sex
Female	977	565 205	1.73	Ref	Ref
Male	379	145 912	2.60	1.49 (1.33 to 1.68)***	1.40 (1.24 to 1.58)***
Age, years
20 – 39	59	123 836	0.48	Ref	Ref
40 – 59	563	368 175	1.53	3.21 (2.45 to 4.19)***	2.89 (2.21 to 3.79)***
≥ 60	734	219 105	3.35	6.98 (5.35 to 9.10)***	5.27 (3.99 to 6.95)***
Comorbidity
DM
No	1127	638 984	1.76	Ref	Ref
Yes	229	72 133	3.17	1.78 (1.55 to 2.06)***	1.14 (0.98 to 1.33)
Hyperlipidaemia
No	974	578 643	1.68	Ref	Ref
Yes	382	132 474	2.88	1.70 (1.51 to 1.92)***	1.10 (0.97 to 1.26)
Hypertension
No	714	499 747	1.43	Ref	Ref
Yes	642	211 370	3.04	2.11 (1.90 to 2.35)***	1.21 (1.07 to 1.38)*
Hyperthyroidism
No	1325	699 624	1.89	Ref	Ref
Yes	31	11 492	2.70	1.41 (0.99 to 2.02)	1.33 (0.92 to 1.92)
IHD
No	987	610 475	1.62	Ref	Ref
Yes	369	100 642	3.67	2.25 (2.00 to 2.54)***	1.36 (1.19 to 1.56)***
Stroke
No	1310	695 656	1.88	Ref	Ref
Yes	46	15 461	2.98	1.55 (1.15 to 2.07)**	0.85 (0.63 to 1.14)
CKD
No	1204	662 599	1.82	Ref	Ref
Yes	152	48 517	3.13	1.71 (1.45 to 2.03)***	1.06 (0.89 to 1.26)
Hypothyroidism
No	1343	706 448	1.90	Ref	Ref
Yes	13	4668	2.78	1.46 (0.85 to 2.52)	1.15 (0.65 to 2.01)
Autoimmune diseases§
No	1334	704 142	1.89	Ref	Ref
Yes	22	6975	3.15	1.65 (1.08 to 2.51)*	1.34 (0.88 to 2.05)

*P<0.05, **P<0.01, ***P<0.001.

†Per 1000 person-years.

‡Multivariate Cox proportional hazards regression model, including RA, sex, age (categorical), DM, hyperlipidaemia, hypertension, hyperthyroidism, IHD, stroke, CKD, hypothyroidism and autoimmune diseases.

§Autoimmune diseases including psoriasis, SLE, systemic sclerosis, Sjogren syndrome, dermatomyositis, polymyositis and vasculitis.

CKD, chronic kidney disease; DM, diabetes mellitus; IHD, ischaemic heart disease; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.