TABLE 3.

Adjusted Difference-in-Differences Estimators of Part D Effect on Outcomes of Interest^a,b

Outcomes	Coefficient (95% CI)	Marginal Effect	P Value
Out-of-pocket expenditures for prescription medicationsc	-0.282 (-0.381, -0.184)	-104.49	< 0.001
Total prescription medication expendituresc	0.028 (-0.057, 0.114)	-5.42	0.516
Number of prescriptions and refillsd	0.032 (-0.078, 0.141)	0.145	0.570
Number of outpatient visitsd	-0.286 (-0.580, 0.009)	-0.242	0.057

^aCovariates included in the models were age, gender, comorbidities, race, marital status, body mass index, education, region, poverty indicator, and self-reported health status.

^bThe estimated average propensity score (SD) for the treatment group and control group was 0.61 (0.0008) and 0.52 (0.0009), respectively.

^cResults were obtained from a 2-part model.

^dResults were obtained from a zero-inflated negative binomial model.

CI = confidence interval; SD = standard deviation.