Table 2.

Use and costs with SS participation 1 and 2 years after index start date

Use measures	Control subjects	SS participants	Adjusted mean difference (Δ SS participants − Δ control subjects)*	P value
n	1,413	618
% hospitalized
Baseline	174 (12.3)	71 (11.5)	—
Year 1	211 (14.9)	74 (11.9)	−3.0 (−6 to 0.2)	0.07
Year 2†	229 (16.2)	70 (11.3)	−4.7 (−7.8 to −1.6)	0.003
Primary care visits/year
Baseline‡	6.2 ± 5.2	6.9 ± 4.8	—
Year 1†	6.2 ± 5.0	7.3 ± 5.2	0.77 (0.34 to 1.2)	<0.001
Year 2†	6.4 ± 5.4	7.0 ± 5.3	0.30 (−0.14 to 0.74)	0.18
Specialty care visits/year
Baseline‡	3.3 ± 3.4	3.7 ± 3.7	—
Year 1	3.6 ± 3.8	3.8 ± 3.6	0.02 (−0.29 to 0.33)	0.92
Year 2†	3.6 ± 3.7	4.0 ± 3.5	0.21 (−0.10 to 0.52)	0.18
Cost measures
Total health care costs ($)
Baseline	6,280 ± 8,365	7,148 ± 11,854	—
Year 1†	8,235 ± 14,752	6,785 ± 8,285	−1,633 (−2,620 to −646)	0.001
Year 2	9,269 ± 15,683	8,113 ± 12,789	−1,230 (−2,494 to 33)	0.06
Inpatient costs ($)
Baseline	1,305 ± 4,810	1,920 ± 8,536	—
Year 1†	2,297 ± 9,613	1,334 ± 4,836	−1,021 (−1,688 to −367)	0.002
Year 2	2,441 ± 9,395	1,956 ± 8,784	−496 (−1,359 to 367)	0.26
Primary care costs ($)
Baseline	956 ± 993	1,077 ± 888	—
Year 1†	1,022 ± 1,224	1,180 ± 1,062	129 (32 to 226)	0.009
Year 2	1,073 ± 1,226	1,157 ± 1,087	49 (−51 to 150)	0.34
Specialty care costs ($)
Baseline‡	908 ± 1,612	947 ± 1,748	—
Year 1	1,037 ± 1,687	949 ± 1,171	−97 (−212 to 18)	0.10
Year 2	1,133 ± 1,847	1,182 ± 1,636	51 (−96 to 199)	0.50

Data are means ± SD or means (95% CI); health care costs are presented in 2003 dollars.

^*Adjusted mean use and costs differences for SS participants and control subjects from multivariate linear regression models using robust SEM estimates that controlled for age, sex, preventive services index, RxRisk (chronic disease score), any arthritis visits at baseline, and respective baseline use and cost measures.

^†Unadjusted year 1 and 2 comparisons between controls and SS participants, P < 0.05.

^‡Baseline unadjusted comparisons between control subjects and SS participants, P < 0.05.