Out-of-pocket costs and adherence to antihypertensive agents among older adults covered by the public drug insurance plan in Quebec

Figures & data

Table 1 An example of how out-of-pocket costs are computed from a $60 CAD prescription filled between January 1 and June 30, 2006

	Deductible per month (CAD)	Coinsurance per month (%)	Out-of-pocket costs (CAD)
Participants with a low income (ie, GIS between 94% and 99%)a	8.33 60−8.33=51.67	25% 51.67×0.25=12.92 CAD	8.33+12.92=21.25
Participants with a high income (ie, GIS <94%)	11.9 60−11.9=48.10	29% 48.10×0.29=13.95 CAD	11.9+13.95=25.85

Note:

a Participants with a maximum GIS (100%) were exempted from out-of-pocket costs from July 1, 2005.

Abbreviations: GIS, Guaranteed income supplement; CAD, Canadian dollars.

Figure 1 Study flow chart.

Abbreviations: AHA, antihypertensive agents; ESA, “Étude sur la santé des aînés”; MED-ECHO, “Maintenance et exploitation des données pour l’étude de la clientèle hôspitalière” [Database on hospitalizations]; MMSE, mini-mental state examination; RAMQ, “Régie de l’Assurance Maladie du Québec” [Quebec’s medical insurance plan].

Figure 2 Time frame for data collection for each participant.

Note: ^aThe baseline interviews (T1) were conducted between February 27, 2005 and November 22, 2007. T2 represented as second interviews.
Abbreviations: ICD-9/10, International Classification of Diseases, 9th or 10th Edition; PDC, proportion of days covered.

Table 2 Classes of antihypertensive agents and comorbidities identified in the participants

Classes of antihypertensive agents identified in the study sample using RAMQ database	Comorbidities that were self-reported during the ESA study by the participants
Alpha-adrenergic blockers	Anemia
ACEi	Eye diseases
ARB	Gastrointestinal diseases
Beta-adrenergic blockers	Hypercholesterolemia
Calcium channel blockers	Metabolism diseases
Direct vasodilators	Rheumatoid arthritis
Nitrates and nitrites Combination pills: ACEi/ACEi, ACEi/beta-adrenergic blockers, ACEi/ARB	Serious back pain or pain in the spine Thyroid diseases Type II diabetes Other cardiovascular diseases

Abbreviations: ACEi, angiotensin converting enzyme inhibitors; ARB, angiotensin II receptor antagonists; ESA, “Étude sur la santé des aînés”; RAMQ, “Régie de l’Assurance Maladie du Québec” [Quebec’s medical insurance plan].

Table 3 Participants’ characteristics by adherence to antihypertensive agents (N=881)

Characteristics	PDC <80%, N=169 (19.2%)	PDC ≥80%, N=712 (80.8%)	P-value
Sex, N (%)
Male	55 (32.7)	267 (37.5)	0.229
Female	114 (67.3)	445 (62.5)
Age (years), N (%)
65–74	88 (52.2)	378 (53.1)	0.799
≥75	81 (47.8)	334 (46.9)
Region, N (%)
Rural	53 (31.4)	259 (36.3)	0.477
Urban	31 (18.3)	112 (15.8)
Metropolitan	85 (50.3)	341 (47.9)
Marital status, N (%)
Married/living as a couple	73 (43.1)	316 (44.4)	0.780
Single/divorced/separated/widowed	96 (56.9)	396 (55.6)
Education (years), N (%)
<10	47 (28)	168 (23.6)	0.251
≥10	122 (72)	544 (76.4)
Annual household income, N (%)
<$15,000 CAD	32 (18.9)	127 (17.8)	0.739
≥$15,000 CAD	137 (81.1)	585 (82.2)
Out-of-pocket costs for AHA at cohort entry, N (%)
$0 CAD	12 (7.1)	88 (12.4)	0.077
$0.01–$5.00 CAD	36 (21.3)	195 (27.4)
$5.01–$10.00 CAD	39 (23.1)	134 (18.8)
$10.01–$15.00 CAD	45 (26.6)	159 (22.3)
$15.01–$36.00 CAD	37 (21.9)	136 (19.1)
Number of AHA per prescription at cohort entry, N (%)
1	121 (71.6)	429 (60.3)	0.009
≥2	48 (28.4)	283 (39.7)
Total number of medications per prescription at cohort entry, median (min, max)	6 (1, 18)	6 (1, 26)	0.031
Depression and/or anxiety, N (%)
No	123 (72.8)	559 (78.6)	0.119
Yes	46 (27.2)	153 (21.4)
Number of comorbidities self-reported, median (min, max)	3 (0, 10)	3 (0, 11)	0.693
Total length of inpatient stays (days), median (min, max)a	0 (0, 27)	0 (0, 116)	0.635

Notes:

a 87.4% of participants were not hospitalized during the study period. Significant results are in bold, P-value <0.05.

Abbreviations: AHA, antihypertensive agents; Min, minimum; Max, maximum; PDC, proportion of days covered; CAD, Canadian dollars.

Table 4 Overall bivariate and multivariable logistic regressions for medication adherence during the 2-year follow-up period (N=881)

Characteristics	Bivariate analysis (N=881)			Multivariable analysis (N=881)
	OR	95% CI	P-value	OR	95% CI	P-value
Sex
Male		Reference			Reference
Female	0.808	0.567–1.153	0.240	0.793	0.539–1.169	0.241
Age (years)
65–74		Reference			Reference
≥75	0.964	0.689–1.349	0.840	0.920	0.645–1.312	0.645
Region
Rural		Reference			Reference
Urban	0.763	0.465–1.251	0.283	1.000	0.622–1.610	0.999
Metropolitan	0.841	0.577–1.227	0.370	1.396	0.840–2.322	0.198
Marital status
Married/living as a couple		Reference			Reference
Single/divorced/separated/widowed	0.950	0.678–1.333	0.768	1.040	0.712–1.519	0.839
Education (years)
<10		Reference			Reference
≥10	1.257	0.862–1.833	0.236	1.423	0.950–2.131	0.087
Annual household income
<$15,000 CAD		Reference			Reference
≥$15,000 CAD	1.076	0.700–1.654	0.738	1.060	0.654–1.718	0.812
Out-of-pocket costs for AHA at cohort entry
$0 CAD		Reference			Reference
$0.01–$5.00 CAD	0.708	0.348–1.439	0.340	0.686	0.328–1.435	0.317
$5.01–$10.00 CAD	0.449	0.220–0.913	0.027	0.467	0.220–0.989	0.047
$10.01–$15.00 CAD	0.446	0.223–0.895	0.023	0.469	0.221–0.998	0.049
$15.01–$36.00 CAD	0.482	0.236–0.985	0.045	0.482	0.220–1.056	0.068
Number of AHA per prescription at cohort entry
1		Reference			Reference
≥2	1.638	1.137–2.360	0.008	1.443	0.964–2.160	0.074
Total number of medications per prescription at cohort entry	1.054	1.003–1.108	0.039	1.015	0.995–1.079	0.635
Depression and/or anxiety
No		Reference			Reference
Yes	0.735	0.501–1.079	0.116	0.689	0.460–1.032	0.071
Number of comorbidities self-reported	1.070	0.976–1.174	0.149	1.041	0.933–1.162	0.468
Total length of inpatient stays	1.025	0.988–1.063	0.190	1.026	0.986–1.067	0.207

Note: Significant results are in bold, P-value <0.05.

Abbreviations: AHA, antihypertensive agents; CAD, Canadian dollars.

Table 5 Multivariable logistic regressions by annual household income, for medication adherence during the 2-year follow-up period

Characteristics	Household income <$15,000 CAD (N=159)			Household income ≥$15,000 CAD (N=722)
	OR	95% CI	P-value	OR	95% CI	P-value
Sex
Male		Reference			Reference
Female	0.517	0.124–2.148	0.364	0.840	0.555–1.273	0.412
Age (years)
65–74		Reference			Reference
≥75	1.660	0.682–4.039	0.264	0.822	0.549–1.230	0.340
Region
Rural		Reference			Reference
Urban	1.145	0.320–4.094	0.835	0.937	0.552–1.593	0.811
Metropolitan	1.765	0.469–6.644	0.401	1.335	0.758–2.349	0.317
Marital status
Married/living as a couple		Reference			Reference
Single/divorced/separated/widowed	1.240	0.279–5.508	0.777	1.021	0.683–1.526	0.921
Education (years)
<10		Reference			Reference
≥10	2.010	0.839–4.813	0.117	1.248	0.775–2.011	0.362
Out-of-pocket costs for AHA at cohort entry
$0 CAD		Reference			Reference
$0.01–$5.00 CAD	1.218	0.349–4.251	0.757	0.194	0.048–0.787	0.022
$5.01–$10.00 CAD	0.797	0.182–3.489	0.763	0.146	0.036–0.589	0.007
$10.01–$15.00 CAD	0.175	0.042–0.740	0.018	0.192	0.047–0.777	0.021
$15.01–$36.00 CAD	1.159	0.207–6.491	0.866	0.160	0.039–0.655	0.011
Number of AHA per prescription at cohort entry
1		Reference			Reference
≥2	0.771	0.307–1.934	0.579	1.735	1.085–2.775	0.021
Total number of medications per prescription at cohort entry	0.864	0.758–0.984	0.028	1.069	0.993–1.151	0.075
Depression and/or anxiety
No		Reference			Reference
Yes	1.093	0.404–2.953	0.861	0.657	0.414–1.041	0.074
Number of comorbidities self-reported	1.153	0.907–1.467	0.245	1.000	0.882–1.133	0.997
Total length of inpatient stays	1.009	0.949–1.073	0.775	1.038	0.968–1.091	0.153

Note: Significant results are in bold, P-value <0.05.

Abbreviations: AHA, antihypertensive agents; CAD, Canadian dollars.