Impact of the change of copay policy in Medicare Part D on zoster vaccine uptake among Medicare beneficiaries in a managed care organization

Table 4 Comparison of zoster vaccination rate between Medicare Part D members and commercial plan members aged 60-64^a

Characteristics	Medicare Part D (65+)	Commercial (60–64)	Difference-in-difference
Characteristics	Rate ratio (2012/2011)	Rate ratio (2012/2011)	Ratio of rate ratio	p-value^b	Difference of rate ratio
Overall	1.57	1.52	1.03 (0.99;1.07)	0.145	0.04 (−0.02;0.10)
Age
60–64	N/A	1.52
65–69	1.55	N/A
70–74	1.53	N/A
75+	1.57	N/A
Sex
Female	1.52	1.47	1.03 (0.98;1.08)	0.265	0.04 (−0.03;0.12)
Male	1.64	1.59	1.03 (0.97;1.09)	0.358	0.05 (−0.05;0.15)
Race/Ethnicity
Non-Hispanic white	1.63	1.54	1.05 (1.00;1.11)	0.034	0.08 (0.00;0.16)
Non-Hispanic black	1.62	1.61	1.01 (0.85;1.19)	0.939	0.01 (−0.28;0.30)
Hispanic	1.48	1.64	0.91 (0.83;0.99)	0.038	−0.15 (−0.30;0.00)
Asian/Pacific Islanders	1.37	1.36	1.01 (0.90;1.13)	0.905	0.01 (−0.15;0.17)
Others/unknown	1.96	1.41	1.39 (1.13;1.71)	0.002	0.55 (0.15;0.95)

ISSN: 1472-6963