Table 4.

Changes in ED use according to primary reason for visit (Clinical Classifications Software category), 2009 to 2011.

CCS Category	Estimated Change in Number of Visits, % (95% CI)*	Estimated Change in Probability of Visit, %†
Overall	−0.5 (−0.8 to −0.1)	0.2 (−0.1 to 0.5)
Injury and poisoning	0.1 (−0.5 to 0.8)	0.5 (−0.1 to 1.1)
Ill-defined conditions	0.1 (−0.8 to 1.0)	0.6 (−0.2 to 1.4)
Complications of pregnancy or childbirth	−3.7 (−4.9 to −2.6)	−3.7 (−4.6 to −2.7)
Respiratory system diseases	−0.8 (−1.7 to 0.1)	−1.0 (−1.9 to −0.2)
Genitourinary diseases	0.3 (−0.7 to 1.3)	0 (−0.9 to 1.0)
Digestive system diseases	−0.2 (−1.2 to 0.9)	−0.4 (−1.4 to 0.6)
Nervous system diseases	−0.1 (−1.2 to 1.0)	0.3 (−0.7 to 1.3)
Mental illness	0.4 (−1.1 to 1.8)	2.6 (1.3 to 3.9)
Musculoskeletal diseases	−0.2 (−1.5 to 1.0)	0.4 (−0.8 to 1.6)
Skin diseases	−3.3 (−4.8 to −1.9)	−3.1 (−4.4 to −1.8)
Circulatory system diseases	4.9 (3.3 to 6.5)	4.8 (3.3 to 6.3)
Infectious diseases	−1.3 (−3.2 to 0.6)	−1.5 (−3.3 to 0.3)
Endocrine and metabolic diseases	0.5 (−2.8 to 3.8)	1.4 (−1.4 to 4.4)
Blood diseases	0.8 (−9.8 to 12.7)	0.9 (−4.6 to 6.7)
Neoplasms	−2.8 (−10.1 to 5.1)	−4.1 (−11.0 to 3.2)
Congenital anomalies	16.6 (−5.4 to 43.6)	14.9 (−2.0 to 34.7)

CCS, Clinical Classifications Software.

^*The modeled relative change in the number of ED visits per patient was estimated with a negative binomial model, with change after the implementation of the ACA provision measured by the interaction of the post-ACA period and the younger age group.

^†The modeled change in the probability of young adults ever using the ED pre-ACA versus post-ACA was estimated with Poisson relative-risk regression analysis, with change after the implementation of the ACA provision measured by the interaction of the post-ACA period and the younger age group.