Table 2.

Rates and Weighted Counts of Primary Care Utilization and Costs Among Young Adults Identified as ASD-Only or ASD+ID Using Different Definitions for Case Identification

Weighted N	ASD-only, 1+ claim, n = 324	ASD-only, 2+ claim, n = 233	Difference in 1+ and 2+ a	ASD+ID, 1+ claim, n = 203	ASD+ID, 2+ claim, n = 131	Difference in 1+ and 2+ a
	N = 6480	N = 4660		N = 4060	N = 2620
Any PCP visit in past yearb
Weighted N	4220	3160	z = −0.66, p = 0.51	2960	1980	z = −0.54, p = 0.59
%	65.12	67.81		72.91	75.57
95% CI	59.66–70.31	61.40–73.76		66.24–78.89	67.30–82.65
Annual number of PCP visits per beneficiary
Mean (SD)	2.18 (3.09)	2.37 (2.91)	z = −0.74, p = 0.46	2.95 (3.38)	3.01 (3.54)	z = −0.15, p = 0.88
Median (IQR)	1 (3)	1 (3)		2 (4)	2 (4)
Annual PCP payment per beneficiaryc (in $)
Mean (SD)	238 (279)	243 (230)	z = −0.19, p = 0.85	289 (277)	280 (289)	z = 0.24, p = 0.81
Median (IQR)	157 (234)	164 (237)		213 (260)	188 (293)

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

Beneficiaries with 12 months fee-for-service, no end-stage renal disease, no missing race/ethnicity.

^a For frequency data, the exact two-sample tests of proportions were used; for count data, the two-sample z-test was used.

^b The denominator for % is total unique beneficiaries in group.

^c Annual PCP payment per beneficiary is equal to the sum of the amount of money paid from Medicare to provider, amount paid from beneficiary to provider, and if there is one, payments made by a secondary payer across all PCP visits in a claim year.

PCP, primary care provider.