Table 2.

Estimated Effects of the Removal of Drug Caps Under Medication Part D on Prevalence and Intensity of Antidepressant Use among Dual Enrollees with Diabetes and Co-Morbid Major Depression by State Drug Cap Status^*

All	Observed At Baseline (Nov 2005)	Baseline Trend		Part D		Trend Change		Absolute Effect 12 Months Post (Dec 2007)†	Relative Effect 12 Months Post (Dec 2007)†
Cap States		Estimate (95% CI)	p-value	Estimate (95% CI)	p-value		p-value
Any Use	11%	0.0002 (−0.0002,0.0005)	0.344	0.04 (0.03,0.05)	<0.0001	0.001 (0.0002, 0.001)	0.010	0.05	45%
SMD‡	0.20	0.0002 (−0.001,0.001)	0.628	0.05 (0.03,0.07)	<0.001	−0.0001 (−0.001,0.001)	0.916	0.04	25%
No Cap States
Any Use	28%	0.001 (0.0004,0.001)	<0.001	−0.01 (−0.01, −0.003)	0.007	−0.0005 (−0.001, −0.0001)	−0.026	−0.02	−3%
SMD‡	0.48	0.001 (0.0005,0.002)	0.001	−0.002 (−0.02,0.01)	0.828	−0.002 (−0.003, −0.0005)	0.005	−0.03	−4%

^*: The 32 no-cap states were: AK, CO, CT, DC, DE, FL, HI, IA, ID, IN, MA, MD, MI, MN, MO, MT, ND, NE, NH, NJ, NM, NV, OR, RI, SD, UT, VA, VT, WA, WI, WV, WY. The 4 strict cap states were: AR, MS, OK, TX. The following 11 states had less restrictive caps: AL, CA, GA, IL, KS, KY, ME, NC, NY, PA, SC. Three states were excluded from the study due to data anomalies: AZ, LA, OH. We also excluded one state due to the introduction of a drug cap during the baseline period: TN.

^†: Attributable differences (absolute and relative) as compared to expected values 1 year after Part D implementation were estimated for December 2007.

^‡: Mean standardized monthly doses (SMDs) calculated across all individuals in cohort, not only those with dispensed claims.