TABLE 6.

Association Between DCCM Intervention in Post-Index Period^a and Medical Charges (GLM Model)

	Base Model				Augmented Model
	Coefficient	95% CI		P Value	Coefficient	95% CI		P Value
Log (total charges)
DCCM intervention in post-index period	-0.423	-0.779	-0.068	0.019	-0.423	-0.768	-0.079	0.016
DCCM group assignment	1.089	0.822	1.356	< 0.001	0.803	0.533	1.073	< 0.001
Post-index period (reference pre-index)	0.441	0.207	0.675	< 0.001	0.441	0.214	0.668	< 0.001
Baseline HbA1c	-0.122	-0.171	-0.074	< 0.001	-0.107	-0.156	-0.059	< 0.001
Other covariatesb	No				Yes
Log (inpatient charges)
DCCM intervention in post-index period	-0.142	-0.610	0.326	0.552	-0.142	-0.608	0.324	0.550
DCCM group assignment	0.609	0.257	0.962	0.001	0.436	0.071	0.801	0.019
Post-index period (reference pre-index)	0.061	-0.248	0.370	0.698	0.061	-0.246	0.368	0.697
Baseline HbA1c	0.019	-0.045	0.083	0.553	0.022	-0.044	0.087	0.511
Other covariatesb	No				Yes
Log (outpatient charges)
DCCM intervention in post-index period	-0.419	-0.757	-0.081	0.015	-0.419	-0.747	-0.092	0.012
DCCM group assignment	1.024	0.770	1.279	< 0.001	0.750	0.493	1.007	< 0.001
Post-index period (reference pre-index)	0.474	0.251	0.697	< 0.001	0.474	0.258	0.690	< 0.001
Baseline HbA1c	-0.130	-0.177	-0.084	< 0.001	-0.115	-0.161	-0.069	< 0.001
Other covariatesb	No				Yes

^a Variable of interest in this difference-in-difference model is variable representing DCCM group in the post-index period, which is the interaction term between DCCM intervention group assignment and a variable indicating the post-index period.

^b Other covariates include age, race, gender, pre-index use of metformin or insulin, number of diabetes classes used pre-index date, and history of retinopathy or chronic kidney disease. See Appendix C (available in online article) for coefficients for other covariates.

CI = confidence interval; DCCM = diabetes collaborative care management; GLM = general linear model; HbA1c = hemoglobin A1c.