Table 2.

Risk Factors for Part D Enrollment Status

	% Enrolled in Part D	Total Population^*
	% Enrolled in Part D	Unadjusted relative risk ratios	Adjusted relative risk ratios
Age
<64	97	Ref	Ref
65–74	88	0.92	0.92^‡
75–84	81	0.84^‡	0.84^‡
85+	78	0.82^‡	0.82^‡
Gender
Male	83	Ref	Ref
Female	83	1.00	1.02^‡
Residence
Northeast	85	1.01^‡	1.01^‡
Midwest	82	0.99^‡	0.99^‡
South	83	Ref	Ref
West	82	0.98^‡	0.98^‡
Normalized Chronic Disease Score in 2005
<.50	87	Ref	Ref
.50–1.50	83	0.96^‡	0.99^‡
>1.50	82	0.94^‡	0.96^‡
Drug coverage in 2005^†
Medicaid	97	1.56^‡	N/A
Third-party	76	0.85^‡	N/A
No coverage	70	0.84^‡	N/A

Includes 459,577 individuals with 2005 and 2006 observations

^†

Reference is all other coverage types.

^‡

p<0.001

N/A= N/A=Drug coverage in 2005 is not included in the full model due to endogeneity with covariates. Stratefied analyses by drug coverage status are available from authors.