Table 1.

Demographic data for all subjects included in this investigation

	Total cohort (n = 2030)	Confirmed RA subgroup (n = 453)	Unconfirmed RA subgroup (n = 1577)
Female, % Age, years Ethnicity, %	79.2 (77.4–81.0) 56.6 (55.9–57.3)	80.6 (76.9–84.2) 59.6 (58.2–61.1)	78.7 (76.7–80.7) 55.7 (54.9–56.5)
Caucasian	68.1 (66.1–70.2)	62.5 (58.0–67.0)	69.8 (67.5–72.0)
African American	14.2 (12.7–15.7)	19.2 (15.6–22.8)	12.8 (11.1–14.4)
Hispanic	1.8 (1.2–2.4)	1.3 (0.27–2.4)	2.0 (1.3–2.7)
Asian	2.0 (1.4–2.6)	1.8 (0.5–3.0)	2.0 (1.3–2.7)
Native Hawaiian	0.1 (0–0.2)	0.2 (0–0.6)	0.1 (0–0.2)
Other	11.3 (9.9–12.7)	11.7 (8.7–14.7)	11.2 (9.6–12.7)
Not stated	2.5 (1.8–3.1)	3.3 (1.7–5.0)	2.2 (1.5–3.0)
ILD, %	2.8 (2.0–3.5)	6.0 (3.8–8.1)	1.8 (1.1–2.5)
Anti-CCP, U/mL	29.5 (26.0–33.0)	113 (101.4–124.7)	5.5 (3.8–7.3)
Rheumatoid factor positive, %	44.8 (39.3–50.3)	69.7 (54.6–84.8)	19.3 (16.6–22.0)
Rheumatoid factor, IU/mL**	81.8 (67.6–96.0)	228.9 (181.4–276.4)	37.5 (26.8–48.2)
Erythrocytic sedimentation rate, mm	25.1 (23.8–26.3)	34.9 (32.1–37.6)	22.0 (20.7–23.3)
C-reactive protein, mg/dL	1.6 (1.4–1.8)	2.0 (1.6–2.4)	1.5 (1.2–1.7)
Hemoglobin, g/dL	12.9 (12.8–13.0)	12.7 (12.5–12.9)	13.0 (12.9–13.0)
Serum albumin, g/dL	3.7 (3.7–3.7)	3.6 (3.6–3.7)	3.8 (3.7–3.8)
Platelets, K/uL	262.3 (258.2–266.4)	276.6 (268.6–284.6)	257.1 (252.3–261.9)

Values are the percentage or mean value followed by 95% confidence interval

^**The lowest reported value is 20 IU/mL. All values reported as < 20 IU/mL were counted as 19 IU/mL