Table 2.

Mean annual incidence of SLE from 2007 through 2009 according to the primary and alternate definitions, categorized by sex and region^*

		Primary definition			Alternate definition
	Person-years of observation	No. of cases	Unadjusted rate (95% CI)	Age-adjusted rate (95% CI)	No. of cases	Unadjusted rate (95% CI)	Age-adjusted rate (95% CI)
Combined regions	649,302	38	5.9 (4.2–8.0)	7.4 (5.1–10.4)	44	6.8 (5.0–9.0)	8.6 (6.1–11.8)
Sex-specific
Female	357,137	30	8.4 (5.8–11.8)	10.4 (6.6–14.6)	36	10.1 (7.2–13.8)	12.1 (8.3–17.1)
Male	292,165	8	2.7 (1.3–5.2)	–	8	2.7 (1.3–5.2)	–
Regional
Alaska	357,419	17	4.8 (2.9–7.5)	6.1 (3.4–10.2)	20	5.6 (3.5–8.5)	7.2 (4.2–11.5)
Phoenix	221,770	18	8.1 (5.0–12.6)	10.7 (6.2–17.5)	21	9.5 (6.0–14.2)	12.7 (7.6–20.1)
Oklahoma	70,113	3	4.3 (1.1–11.7)	–	3	4.3 (1.1–11.7)	–

^*Rates are per 100,0000 person-years. Age-adjusted rates were calculated using the 2000 projected US population and 10-year age groups (14). The primary definition is documentation in the medical record of ≥4 of 11 American College of Rheumatology (ACR) classification criteria for systemic lupus erythematosus (SLE). The alternate definition is the primary definition or documentation of ≥3 ACR criteria and a final diagnosis of SLE made by the treating rheumatologist. 95% CI = 95% confidence interval.