Table 1.

Comparison of the Proportional Values of Dichotomous Demographic Characteristics for the 1 + Versus 2+ Samples from 5% Limited Data Set Medicare File, 2010

Variable	Study group	1+ Diagnosis occurrence proportion % a	95% CI for exact binomial proportions	2+ Diagnosis occurrence proportion % b	95% CI for exact binomial proportions	p-Value, difference in 1+ and 2+
Gender: male
	ASD-only	79.63	74.83–83.88	81.12	75.49–85.93	0.66
	ASD and ID	77.83	71.49–83.35	79.39	71.45–85.96	0.74
Age group: 22–27
	ASD-only	74.07	68.94–78.76	77.68	71.79–82.86	0.33
	ASD and ID	80.79	74.69–85.97	83.21	75.69–89.17	0.58
Hispanic status: Hispanic
	ASD-only	5.25	3.09–8.27	5.58	3.00–9.35	0.86
	ASD and ID	7.88	4.57–12.48	6.11	2.67–11.68	0.54
Minority status: nonwhite
	ASD-only	24.69	20.09–29.76	24.89	19.48–30.96	0.96
	ASD and ID	37.44	30.76–44.49	37.40	29.11–46.28	0.99
Medicaid: has 12 months state buy-in
	ASD-only	82.72	78.15–86.67	83.69	78.31–88.19	0.65
	ASD and ID	88.67	83.49–92.68	87.02	80.04–92.26	0.69
		1+ Diagnosis occurrence mean (SD) a	1+ Diagnosis occurrence median	2+ Diagnosis occurrence mean (SD) b	2+ Diagnosis occurrence median	z-Test p-value
ACG® score
	ASD-only	2.25 (2.85)	1.27	2.35 (2.95)	1.27	0.69
	ASD and ID	3.60 (4.00)	2.31	3.31 (3.41)	2.31	0.48

Data source: Centers for Medicare and Medicaid, Medicare Limited Data Set 2010 file for 5% carrier file (professional service file).

Comparison categories include gender: female; age: 18–21 years; Hispanic status: non-Hispanic; minority status: white; Medicaid: does not have Medicaid state buy-in.

^a 1+ Sample included unweighted (5% file): ASD-only, n = 324, ASD+ID, n = 203; 1+ sample weighted ASD-only, N = 6480, ASD+ID, N = 4060.

^b 2+ Sample included unweighted (5% file): ASD-only, n = 233, ASD+ID, n = 131; 2+ sample weighted ASD-only, N = 4660, ASD+ID, N = 2620.

ACG, Adjusted Clinical Groups; ASD, autism spectrum disorder; ASD+ID, autism spectrum disorder plus intellectual disability; CI, confidence interval; ID, intellectual disability.