Risk factors for cost-related medication non-adherence among older patients with diabetes

Table 1 Prevalence of cost-related medication non-adherence by Socio-Demographics, Health Status and Usage of Medical Resources n (%)

	All	Reported CRN	Did not report CRN	P value
Full sample	4880 (100)	875 (18)	4005 (82)
Age
≥ 50 and ≤ 64	2031 (100)	573 (28)	1458 (72)
≥ 65 and ≤ 74	1505 (100)	207 (14)	1298 (86)
≥ 75 and ≤ 84	1017 (100)	82 (8)	935 (92)	< 0.001
≥ 85	329 (100)	13 (4)	314 (96)
Gender
Male	2224 (100)	343 (15)	1881 (85)
Female	2656 (100)	532 (20)	2124 (80)	< 0.001
Race
White	3298 (100)	502 (15)	2796 (85)
African-American	1187 (100)	277 (23)	910 (77)
Other	393 (100)	94 (24)	299 (76)	< 0.001
Ethnicity
Hispanic	883 (100)	189 (21)	694 (79)
Non-Hispanic	3997 (100)	686 (17)	3311 (83)	0.003
Nursing Home
Living in NH	138 (100)	7 (5)	131 (95)
Not in NH	4742 (100)	868 (18)	3874 (82)	< 0.001
Insurance coverage for Rx
Yes	4461 (100)	716 (16)	3745 (84)
No	419 (100)	159 (38)	260 (62)	< 0.001
Medicaid coverage
Currently covered	349 (100)	24 (7)	325 (93)
Not covered	4531 (100)	851 (19)	3680 (81)	< 0.001
ADL limitations
No limitation	3455 (100)	519 (15)	2936 (85)
1 or more limitations	1425 (100)	356 (25)	1069 (75)	< 0.001
IADL limitations
No limitation	3442 (100)	547 (16)	2895 (84)
1 or more limitations	1438 (100)	328 (23)	1110 (77)	< 0.001
Hospitalization
No hospitalization	3081 (100)	486 (16)	2595 (84)
1 or more hospitalizations	1799 (100)	389 (22)	1410 (78)	< 0.001
Monthly out-of-pocket payments for Rx
Payments: $ (s.d.)	69 (2.4)	108 (6.9)	60 (2.5)	< 0.001

P values by χ² tests, except for out-of-pocket payments for Rx, where t-test was performed. CRN: Cost-related medication non-adherence; ADL: Activities of daily living; IADL: Instrumental activities of daily living.

Table 2 Results of Multivariate Logistic Regression Analysis of Cost-related Medication Non-adherence

	OR	P value	95%CI
Age
Age 50-64	2.182	< 0.001	1.805-2.638
Age 65-74	Reference	-	-
Age 75-84	0.532	< 0.001	0.403-0.704
Age ≥ 85	0.236	< 0.001	0.131-0.426
Residence
Nursing home residence	0.335	0.011	0.145-0.775
Medicare insurance coverage
No drug coverage	2.824	< 0.001	2.233-3.570
Medicaid coverage
Currently covered by Medicaid	0.341	< 0.001	0.217-0.535
Functional limitations
Activities of daily living
No limitation	Reference	-	-
1 limitation	1.431	0.005	1.113-1.840
2 limitations	1.850	< 0.001	1.348-2.540
3 limitations	1.813	0.003	1.229-2.674
4 limitations	1.796	0.012	1.137-2.838
5 limitations	1.776	0.023	1.083-2.911
6 limitations	1.669	0.162	0.813-3.425
Instrumental activities of daily living
No limitation	Reference	-	-
1 limitation	1.376	0.006	1.094-1.731
2 limitations	1.494	0.014	1.084-2.060
3 limitations	1.243	0.307	0.819-1.887
4 limitations	0.872	0.651	0.482-1.579
Number of hospitalizations
No hospitalization	Reference	-	-
1 hospitalization	1.320	0.010	1.068-1.632
2 hospitalizations	1.437	0.011	1.089-1.898
3 hospitalizations	1.683	0.005	1.168-2.424
4 or more hospitalizations	1.507	0.013	1.091-2.082
Medication use for common conditions
Cholesterol	1.118	0.202	0.942-1.327
Pain	1.090	0.320	0.942-1.327
Asthma	1.295	0.011	1.062-1.578
Stomach	1.141	0.186	0.939-1.388
Sleep	1.077	0.516	0.861-1.347
Anxiety	1.082	0.453	0.880-1.330

Results from multivariate logistic regression analysis.