Table 2. Risk of Depression According to RA Status and Serologic Status of RA^a.

	No.	Events, No.	Duration, PY	Incidence rate (per 1000 PY)	HR (95% CI)
					Model 1	Model 2	Model 3
By RA status
Control	192 435	20 641	841 495.3	24.53	1 [Reference]	1 [Reference]	1 [Reference]
RA	38 487	6422	158 423.7	40.54	1.65 (1.61-1.70)	1.67 (1.62-1.71)	1.66 (1.61-1.71)
By RA status and seropositivity
Control	192 435	20 641	841 495.3	24.53	1 [Reference]	1 [Reference]	1 [Reference]
SNRA	11 645	1846	46 776.5	39.46	1.61 (1.53-1.69)	1.74 (1.66-1.83)	1.73 (1.65-1.81)
SPRA	26 842	4576	111 647.2	40.99	1.67 (1.62-1.73)	1.64 (1.58-1.69)	1.64 (1.58-1.69)
By seropositivity
SNRA	11 645	1846	46 776.5	39.46	1 [Reference]	1 [Reference]	1 [Reference]
SPRA	26 842	4576	111 647.2	40.99	1.04 (0.99-1.10)	0.95 (0.90-1.00)	0.96 (0.91-1.01)

Abbreviations: PY, person-years; RA, rheumatoid arthritis; SNRA, seronegative RA; SPRA, seropositive RA.

^a Model 1 was nonadjusted; model 2 was adjusted for age, sex, smoking, alcohol drinking, physical activity, and income; model 3 was adjusted additionally for body mass index, diabetes, hypertension, hyperlipidemia, and chronic kidney disease.