Mail-order pharmacy use and medication adherence among Medicare Part D beneficiaries with diabetes

Figures & data

Table 1.  Characteristics of the overall study sample, mail-order group, and retail pharmacy group before propensity score matching.

Study Variable	Overall Study Sample	Mail-order	Retail Pharmacy	P-Value
	(N = 22,546)	(N = 1496)	(N = 18,854)	(Mail-order vs. Retail)
Age, mean (SD)	72.3 (9.6)	73.0 (7.0)	72.2 (10.0)	0.884
≥65	20,067 (89.0%)	1425 (95.3%)	16,550 (87.8%)	<0.001
Gender female	11,512 (51.1%)	732 (48.9%)	9706 (51.5%)	0.058
Health plan type				<0.001
PDP	17,469 (77.5%)	1037 (69.3%)	14,758 (78.3%)
MAPD	5077 (22.5%)	459 (30.7%)	4096 (21.7%)
CDS, mean (SD)	4.7 (2.4)	4.5 (2.2)	4.6 (2.4)	0.855
0–3	10,639 (47.2%)	765 (51.1%)	8883 (47.1%)	<0.001
4–5	3800 (16.9%)	187 (12.5%)	3298 (17.5%)
≥6	8107 (36.0%)	544 (36.4%)	6673 (35.4%)
Index medication				0.964
Generic	19,299 (85.6%)	1277 (85.4%)	16,102 (85.4%)
Brand	3247 (14.4%)	219 (14.6%)	2752 (14.6%)
Number of distinct medications, mean (SD)	5.1 (2.9)	5.2 (2.5)	5.0 (3.0)	<0.001
Duration of anti-diabetic treatment (in months), mean (SD)	2.7 (1.7)	2.9 (1.7)	2.7 (1.7)	<0.001

Values are number (%) unless noted otherwise. SD = standard deviation; PDP = stand-alone Prescription Drug Plan; MAPD = Medicare Advantage Prescription Drug plan; CDS = Chronic Disease Score.

Table 2.  Characteristics of the mail-order users and retail pharmacy users after propensity score matching.

Study Variable	Mail-order	Retail Pharmacy	P-Value
	(N = 1361)	(N = 1361)
Age, mean (SD)	72.8 (6.7)	72.9 (6.5)	0.748
Female	672 (49.4%)	665 (48.9%)	0.791
Health plan type			1.000
PDP	998 (73.3%)	998 (73.3%)
MAPD	363 (26.7%)	363 (26.7%)
CDS, mean (SD)	4.4 (2.1)	4.5 (2.4)	0.185
0–3	718 (52.8%)	721 (53.0%)	0.139
4–5	163 (12.0%)	149 (11.0%)
≥6	480 (35.3%)	491 (36.1%)
Index medication			0.330
Generic	1160 (85.2%)	1178 (86.6%)
Brand	201 (14.8%)	183 (13.5%)
Number of distinct medications, mean (SD)	5.1 (2.3)	5.0 (2.4)	0.163
Duration of anti-diabetic treatment (in months), mean (SD)	2.9 (1.7)	2.9 (1.7)	0.259

Values are number (%) unless noted otherwise. SD = standard deviation; PDP = stand-alone Prescription Drug Plan; MAPD = Medicare Advantage Prescription Drug plan; CDS = Chronic Disease Score.

Table 3.  Adherence to oral anti-diabetic medications.

Adherence	Mail-order vs. retail pharmacy (before matching)			Mail-order vs. retail pharmacy (after matching)
	Mail-Order	Retail Pharmacy	P-value	Mail-Order	Retail Pharmacy	P-Value
	(N = 1496)	(N = 18,854)		(N = 1361)	(N = 1361)
PDC, mean (SD)	0.68 (0.31)	0.57 (0.36)	<0.001	0.68 (0.31)	0.61 (0.34)	<0.001
Proportion of patients who attained good adherence	49.1%	38.5%	<0.001	49.7%	42.8%	<0.001

PDC = proportion of days covered; SD = standard deviation.