Table 4 The incidence rate and incidence rate ratio of cataracts in the systemic lupus erythematosus cohort and comparison cohort (N = 5225)

Disorder (ICD-9-CM)		SLE cohort (n = 468)			comparison cohort (n = 4757)			IRR (95% CI)	Adjusted IRR^a (95% CI)
		No. of patient	Person-years	IR	No. of patient	Person-years	IR	P	P
Cataracts (366)	Overall	62	2844	21.80	274	31,421	8.72	2.50 (1.90–3.29) < 0.001	3.18 (2.39–4.22) < 0.001
	Sex
	male	9	235	38.30	61	3060	19.93	1.92 (0.96–3.87) 0.067	2.13 (1.03–4.38) 0.041
	female	53	2609	20.31	213	28,361	7.51	2.70 (2.00–3.65) < 0.001	3.50 (2.56–4.80) < 0.001
	Age group (years)
	20–39	15		8.26		18,926	0.69	12.03 (5.73–25.28) < 0.001	13.93 (6.49–29.90) < 0.001
	40–59	34	1815	36.29	13	10,804	13.24	2.74 (1.89–3.98) < 0.001	2.78 (1.89–4.09) < 0.001
	> 60	13	937	141.30	143	1692	69.74	2.02 (1.14–3.59) 0.016	2.03 (1.11–3.71) 0.022

CI Confidence interval, ICD-9-CM International Classification of Diseases, Ninth revision, clinical modification, IR Incidence rate per 1000 person-years, IRR Incidence rate ratio; n.c. Not calculable, SLE Systemic lupus erythematosus
^aAdjusted for age, sex, socioeconomic status, and geographic region

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