Extent and Factors Associated with Adherence to Antidepressant Treatment During Acute and Continuation Phase Depression Treatment Among Older Adults with Dementia and Major Depressive Disorder

Figures & data

Table 1 Baseline Characteristics of Antidepressant Adherent and Non-Adherent Groups During Acute Phase Medicare 5% Sample Claims Data (2012–2013)

		Overall		Adherent		Non-Adherent		χ2	df	p-value
		N = 6239	%	N = 4644	%	N = 1595	%
Age Group								3.118	1	0.077
	65–74 years	985	15.8	711	72.2	274	27.8
	75+ years	5254	84.2	3933	74.9	1321	25.1
Gender								0.006	1	0.939
	Male	1573	25.2	1172	74.5	401	25.5
	Female	4666	74.8	3472	74.4	1194	25.6
Race/Ethnicity*								17.158	1	<0.001
	White	5539	88.8	4168	75.2	1371	24.8
	Other	700	11.2	476	68.0	224	32.0
Public Assistance*								13.529	1	<0.001
	Yes	1949	31.2	1392	71.4	557	28.6
	No	4290	68.8	3252	75.8	1038	24.2
Region								8.848	3	0.031
	Northeast	1280	20.5	969	75.7	311	24.3
	South	2483	39.8	1815	73.1	668	26.9
	Midwest	1724	27.6	1317	76.4	407	23.6
	West	752	12.1	543	72.2	209	27.8
Metropolitan Status								0.130	1	0.718
	Yes	4960	79.5	3697	74.5	1263	25.5
	No	1279	20.5	947	74.0	332	26.0
Baseline PD								5.524	1	0.019
	Yes	368	5.9	293	79.6	75	20.4
	No	5871	94.1	4351	74.1	1520	25.9
Baseline Psychotherapy								4.902	1	0.027
	Yes	771	12.4	599	77.7	172	22.3
	No	5468	87.6	4045	74.0	1423	26.0
Provider Specialty								6.514	4	0.164
	General Family	4682	75.0	3493	74.6	1189	25.4
	Neurology	152	2.4	116	76.3	36	23.7
	Psychiatry	375	6.0	290	77.3	85	22.7
	Other	889	14.2	650	73.1	239	26.9
	Unknown	141	2.3	95	67.4	46	32.6
Density of Neurologists								9.503	3	0.023
	0	1218	19.5	916	75.2	302	24.8
	1	1678	26.9	1248	74.4	430	25.6
	2	1674	26.8	1204	71.9	470	28.1
	3	1669	26.8	1276	76.5	393	23.5
Density of Psychiatrists								5.304	3	0.151
	0	903	14.5	663	73.4	240	26.6
	1	1780	28.5	1298	72.9	482	27.1
	2	1777	28.5	1352	76.1	425	23.9
	3	1779	28.5	1331	74.8	448	25.2
ELX Index								2.870	3	0.412
	0	1033	16.6	772	74.7	261	25.3
	1	1019	16.3	775	76.1	244	23.9
	2	985	15.8	717	72.8	268	27.2
	3	3202	51.3	2380	74.3	822	25.7
Baseline Medication Use
ACE Inhibitors								0.582	1	0.446
	Yes	1567	25.1	1155	73.7	412	26.3
	No	4672	74.9	3489	74.7	1183	25.3
Anticoagulants								0.010	1	0.921
	Yes	735	11.8	546	74.3	189	25.7
	No	5504	88.2	4098	74.5	1406	25.5
Antidiabetic								0.110	1	0.740
	Yes	1090	17.5	807	74.0	283	26.0
	No	5149	82.5	3837	74.5	1312	25.5
Antiparkinsonian								0.733	1	0.392
	Yes	412	6.6	314	76.2	98	23.8
	No	5827	93.4	4330	74.3	1497	25.7
Antipsychotic								2.937	1	0.087
	Yes	996	16.0	763	76.6	233	23.4
	No	5243	84.0	3881	74.0	1362	26.0
Anxiolytic								0.346	1	0.556
	Yes	1019	16.3	751	73.7	268	26.3
	No	5220	83.7	3893	74.6	1327	25.4
ARB								2.325	1	0.127
	Yes	811	13.0	586	72.3	225	27.7
	No	5428	87.0	4058	74.8	1370	25.2
Statin								<0.001	1	0.994
	Yes	2233	35.8	1662	74.4	571	25.6
	No	4006	64.2	2982	74.4	1024	25.6
PPI								2.350	1	0.125
	Yes	1842	29.5	1347	73.1	495	26.9
	No	4397	70.5	3297	75.0	1100	25.0
Beta-Blocker								3.187	1	0.074
	Yes	2433	39.0	1781	73.2	652	26.8
	No	3806	61.0	2863	75.2	943	24.8
CCB								1.155	1	0.283
	Yes	1468	23.5	1077	73.4	391	26.6
	No	4771	76.5	3567	74.8	1204	25.2
Diuretic								3.771	1	0.052
	Yes	2156	34.6	1573	73.0	583	27.0
	No	4083	65.4	3071	75.2	1012	24.8

Notes: Analysis based on 6239 (4644 adherent and 1595 non-adherent) older adults with dementia and newly diagnosed major depression. Results are based on chi-square analysis. In terms of the density of neurologists and psychiatrists, the category 0 represents zero neurologists/psychiatrists in the zip-code and the categories 1, 2, and 3 represent the first, second, and third tertiles, respectively, of non-zero densities. *Represents statistical significance (p-value <0.01).

Abbreviations: df, degrees of freedom; ACE inhibitors, angiotensin-converting enzyme inhibitors; ARBs, angiotensin receptor blockers; PPI, proton pump inhibitor; CCB, calcium channel blockers; ELX, Elixhauser; PD, Parkinson’s disease.

Table 2 Baseline Characteristics of Antidepressant Adherent and Non-Adherent Groups During Continuation Phase Medicare 5% Sample Claims Data (2012–2013)

		Overall		Adherent		Non-Adherent		χ2	df	p-value
		N=5617	%	N=3584	%	N=2033	%
Age Group								5.814	1	0.016
	65–74 years	925	16.5	558	60.3	367	39.7
	75+ years	4692	83.5	3026	64.5	1666	35.5
Gender								0.082	1	0.775
	Male	1383	24.6	878	63.5	505	36.5
	Female	4234	75.4	2706	63.9	1528	36.1
Race/Ethnicity*								26.740	1	<0.001
	White	4984	88.7	3239	65.0	1745	35.0
	Other	633	11.3	345	54.5	288	45.5
Public Assistance								6.431	1	0.011
	Yes	1721	30.6	1056	61.4	665	38.6
	No	3896	69.4	2528	64.9	1368	35.1
Region*								11.731	3	0.008
	Northeast	1171	20.8	789	67.4	382	32.6
	South	2216	39.5	1381	62.3	835	37.7
	Midwest	1547	27.5	999	64.6	548	35.4
	West	683	12.2	415	60.8	268	39.2
Metropolitan Status								0.428	1	0.513
	Yes	4469	79.6	2861	64.0	1608	36.0
	No	1148	20.4	723	63.0	425	37.0
Baseline PD								3.349	1	0.067
	Yes	339	6.0	232	68.4	107	31.6
	No	5278	94.0	3352	63.5	1926	36.5
Baseline Psychotherapy								1.759	1	0.185
	Yes	687	12.2	454	66.1	233	33.9
	No	4930	87.8	3130	63.5	1800	36.5
Provider Specialty								5.070	4	0.280
	General Family	4182	74.5	2686	64.2	1496	35.8
	Neurology	137	2.4	90	65.7	47	34.3
	Psychiatry	351	6.2	232	66.1	119	33.9
	Other	818	14.6	496	60.6	322	39.4
	Unknown	129	2.3	80	62.0	49	38.0
Density of Neurologists								5.407	3	0.144
	0	1100	19.6	697	63.4	403	36.6
	1	1507	26.8	966	64.1	541	35.9
	2	1503	26.8	929	61.8	574	38.2
	3	1507	26.8	992	65.8	515	34.2
Density of Psychiatrists								5.735	3	0.125
	0	811	14.4	497	61.3	314	38.7
	1	1586	28.2	996	62.8	590	37.2
	2	1605	28.6	1056	65.8	549	34.2
	3	1615	28.8	1035	64.1	580	35.9
ELX Index								4.924	3	0.177
	0	962	17.1	584	60.7	378	39.3
	1	949	16.9	614	64.7	335	35.3
	2	896	16.0	580	64.7	316	35.3
	3	2810	50.0	1806	64.3	1004	35.7
Baseline Medication Use
ACE Inhibitors								0.295	1	0.587
	Yes	1427	25.4	902	63.2	525	36.8
	No	4190	74.6	2682	64.0	1508	36.0
Anticoagulants								0.023	1	0.880
	Yes	650	11.6	413	63.5	237	36.5
	No	4967	88.4	3171	63.8	1796	36.2
Antidiabetics								0.663	1	0.415
	Yes	975	17.4	611	62.7	364	37.3
	No	4642	82.6	2973	64.0	1669	36.0
Antiparkinsonian								0.189	1	0.664
	Yes	376	6.7	236	62.8	140	37.2
	No	5241	93.3	3348	63.9	1893	36.1
Antipsychotic*								15.699	1	<0.001
	Yes	887	15.8	618	69.7	269	30.3
	No	4730	84.2	2966	62.7	1764	37.3
Anxiolytic								1.989	1	0.158
	Yes	926	16.5	572	61.8	354	38.2
	No	4691	83.5	3012	64.2	1679	35.8
ARB								2.880	1	0.090
	Yes	744	13.2	454	61.0	290	39.0
	No	4873	86.8	3130	64.2	1743	35.8
Statins								0.954	1	0.329
	Yes	2031	36.2	1279	63.0	752	37.0
	No	3586	63.8	2305	64.3	1281	35.7
PPI								2.487	1	0.115
	Yes	1658	29.5	1032	62.2	626	37.8
	No	3959	70.5	2552	64.5	1407	35.5
Beta-Blockers								1.981	1	0.159
	Yes	2178	38.8	1365	62.7	813	37.3
	No	3439	61.2	2219	64.5	1220	35.5
CCB								2.466	1	0.116
	Yes	1318	23.5	817	62.0	501	38.0
	No	4299	76.5	2767	64.4	1532	35.6
Diuretic								1.262	1	0.261
	Yes	1895	33.7	1190	62.8	705	37.2
	No	3722	66.3	2394	64.3	1328	35.7

Notes: Analysis based on 5617 (3584 adherent and 2033 non-adherent) older adults with dementia and newly diagnosed major depression. Results are based on chi-square analysis. In terms of the density of neurologists and psychiatrists, the category 0 represents zero neurologists/psychiatrists in the zip-code and the categories 1, 2, and 3 represent the first, second, and third tertiles, respectively, of non-zero densities. *Represents statistical significance (p-value<0.01).

Abbreviations: df, degrees of freedom; ACE inhibitors, angiotensin-converting enzyme inhibitors; ARBs, angiotensin receptor blockers; PPI, proton pump inhibitor; CCB, calcium channel blockers; ELX, Elixhauser; PD, Parkinson’s disease.

Table 3 Description of Antidepressant Medication Initiation by Class-Level and Individuals-Level in Acute and Continuation Phase Medicare 5% Sample Claims Data (2012–2013)

Acute Phase
		Adherent		Non-Adherent		χ^2	df	p-value
		N	%	N	%
Antidepressant Class*						20.700	4	<0.001
	SSRI	3055	75.6	987	24.4
	SNRI	512	75.0	171	25.0
	Tetracyclic	629	71.3	253	28.7
	Phenylpiperazine	285	67.2	139	32.8
	Others	163	78.4	45	21.6
Individual Antidepressant
	Bupropion	141	78.3	39	21.7
	Citalopram	1037	75.1	344	24.9
	Desvenlafaxine	21	72.4	8	27.6
	Duloxetine	310	74.3	107	25.7
	Escitalopram	720	76.4	223	23.6
	Fluoxetine	236	72.6	89	27.4
	Fluoxetine/olanzapine	1	100.0	-	0.0
	Fluvoxamine	6	85.7	1	14.3
	Mirtazapine	629	71.3	253	28.7
	Nefazodone	1	100.0	-	0.0
	Selegiline	1	33.3	2	66.7
	Sertraline	1056	76.2	330	23.8
	Trazodone	284	67.1	139	32.9
	Venlafaxine	181	76.4	56	23.6
	Vilazodone	20	83.3	4	16.7

Continuation Phase
		Adherent		Non-Adherent		χ^2	df	p-value
		N	%	N	%
Antidepressant Class*						15.199	4	0.004
	SSRI	2367	64.6	1297	35.4
	SNRI	409	65.0	220	35.0
	Tetracyclic	457	60.4	299	39.6
	Phenylpiperazine	216	57.4	160	42.6
	Others	135	70.3	57	29.7
Individual Antidepressant
	Bupropion	118	71.1	48	28.9
	Citalopram	799	63.4	461	36.6
	Desvenlafaxine	19	73.1	7	26.9
	Duloxetine	242	63.5	139	36.5
	Escitalopram	569	66.1	292	33.9
	Fluoxetine	179	61.3	113	38.7
	Fluoxetine/olanzapine	1	100.0	-	0.0
	Fluvoxamine	6	100.0	-	0.0
	Mirtazapine	457	60.4	299	39.6
	Nefazodone	1	100.0	-	0.0
	Selegiline	-	0.0	2	100.0
	Sertraline	814	65.4	431	34.6
	Trazodone	215	57.3	160	42.7
	Venlafaxine	148	66.7	74	33.3
	Vilazodone	16	69.6	7	30.4

Notes: Analysis based on 6239 (4644 adherent and 1595 non-adherent) and 5617 (3584 adherent and 2033 non-adherent) older adults with dementia and newly diagnosed major depression during acute and continuation phase depression treatment. Chi-square analysis was conducted only on the overall antidepressant classes between adherent and Non-adherent groups during acute and continuation phase depression treatment. *Represents statistical significance (p-value<0.01).

Abbreviations: SSRI, selective serotonin reuptake inhibitor; SNRI, serotonin–norepinephrine reuptake inhibitor.

Table 4 Predictors of Adherence During Acute Phase Depression Treatment

	AOR	99% CI		Wald χ^2	p-value
		Lower CL	Upper CL
Age Group
75+ years vs 65–74 years	1.14	0.93	1.40	2.61	0.106
Gender
Female vs Male	1.03	0.86	1.23	0.21	0.649
Race/Ethnicity*
White vs Others	1.30	1.02	1.66	7.99	0.005
Public Assistance
Yes vs No	0.86	0.73	1.02	5.03	0.025
Region				2.93	0.403
Northeast vs South	1.03	0.83	1.29
West vs South	1.00	0.78	1.29
Midwest vs South	1.13	0.93	1.37
Metropolitan Status
Yes vs No	1.02	0.80	1.29	0.04	0.845
Baseline Parkinson’s Disease
Yes vs No	1.39	0.92	2.10	4.16	0.041
Baseline Psychotherapy
Yes vs No	1.22	0.95	1.56	4.31	0.038
Provider Specialty				5.20	0.268
Neurology vs General/Family	1.05	0.63	1.75
Psychiatry vs General/Family	1.10	0.78	1.54
Other vs General/Family	0.92	0.74	1.14
Unknown vs General/Family	0.71	0.44	1.14
Density of Neurologists				10.54	0.015
1 vs 0	0.81	0.60	1.11
2 vs 0	0.69	0.50	0.96
3 vs 0	0.83	0.58	1.18
Density of Psychiatrists				10.19	0.017
1 vs 0	1.14	0.83	1.56
2 vs 0	1.44	1.01	2.05
3 vs 0	1.30	0.89	1.90
ELX Index				2.60	0.458
1 vs 0	1.09	0.83	1.42
2 vs 0	0.92	0.71	1.20
≥3 vs 0	1.01	0.80	1.26
ACE Inhibitors
Yes vs No	0.97	0.81	1.17	0.15	0.695
Anticoagulant
Yes vs No	1.01	0.80	1.29	0.02	0.898
Antidiabetic
Yes vs No	1.08	0.87	1.33	0.80	0.371
Antiparkinsonian
Yes vs No	0.94	0.65	1.37	0.17	0.679
Antipsychotic
Yes vs No	1.18	0.95	1.46	3.76	0.053
Anxiolytic
Yes vs No	0.97	0.79	1.19	0.12	0.728
ARB
Yes vs No	0.94	0.74	1.19	0.49	0.482
Statin
Yes vs No	1.07	0.90	1.26	0.96	0.327
PPI
Yes vs No	0.94	0.80	1.12	0.79	0.375
Beta-blocker
Yes vs No	0.92	0.78	1.08	1.79	0.181
CCB
Yes vs No	0.98	0.82	1.18	0.07	0.795
Diuretic
Yes vs No	0.92	0.78	1.09	1.49	0.222

Notes: Analysis based on 6239 (4644 adherent and 1595 non-adherent) older adults with dementia and newly diagnosed major depression. Results are based on multiple logistic regression analysis. In terms of the density of neurologists and psychiatrists, the category 0 represents zero neurologists/psychiatrists in the zip-code and the categories 1, 2, and 3 represent the first, second, and third tertiles, respectively, of non-zero densities. Global Wald chi-square was significant, χ2 ₍₃₅₎ = 76.208, p < 0.001. *Represents statistical significance (p-value <0.01).

Abbreviations: AOR, adjusted odds ratio; CI, confidence intervals; ACE inhibitors, angiotensin-converting enzyme inhibitors; ARBs, angiotensin receptor blockers; PPI, proton pump inhibitor; CCB, calcium channel blockers; ELX, Elixhauser.

Table 5 Predictors of Adherence During Continuation Phase Depression Treatment

	AOR	99% CI		Wald χ^2	p-value
		Lower CL	Upper CL
Age Group
75+ years vs 65–74 years	1.16	0.95	1.42	3.85	0.050
Gender
Female vs Male	1.05	0.89	1.25	0.61	0.435
Race/Ethnicity*
White vs Others	1.49	1.18	1.89	18.79	<0.001
Public Assistance
Yes vs No	0.93	0.79	1.10	1.10	0.294
Region				3.97	0.265
Northeast vs South	1.16	0.94	1.43
West vs South	0.99	0.77	1.26
Midwest vs South	1.07	0.89	1.28
Metropolitan Status
Yes vs No	0.99	0.78	1.24	0.02	0.886
Baseline Parkinson’s Disease
Yes vs No	1.36	0.93	1.99	4.28	0.039
Baseline Psychotherapy
Yes vs No	1.03	0.82	1.30	0.11	0.738
Provider Specialty				5.22	0.266
Neurology vs General/Family	1.09	0.67	1.76
Psychiatry vs General/Family	1.01	0.74	1.39
Other vs General/Family	0.84	0.69	1.04
Unknown vs General/Family	0.90	0.56	1.46
Density of Neurologists				4.64	0.201
1 vs 0	0.87	0.65	1.17
2 vs 0	0.79	0.58	1.09
3 vs 0	0.90	0.64	1.25
Density of Psychiatrists				7.74	0.052
1 vs 0	1.19	0.88	1.62
2 vs 0	1.40	1.00	1.97
3 vs 0	1.26	0.87	1.82
ELX Index				7.21	0.066
1 vs 0	1.22	0.95	1.56
2 vs 0	1.23	0.95	1.58
≥3 vs 0	1.23	1.00	1.52
ACE Inhibitors
Yes vs No	1.00	0.83	1.19	0.00	0.945
Anticoagulant
Yes vs No	0.97	0.77	1.23	0.09	0.768
Antidiabetic
Yes vs No	1.02	0.83	1.24	0.04	0.840
Antiparkinsonian
Yes vs No	0.79	0.56	1.12	3.02	0.082
Antipsychotic*
Yes vs No	1.43	1.16	1.76	18.80	<0.001
Anxiolytic
Yes vs No	0.91	0.75	1.10	1.67	0.196
ARB
Yes vs No	0.94	0.75	1.18	0.47	0.494
Statin
Yes vs No	1.00	0.85	1.17	0.00	0.981
PPI
Yes vs No	0.94	0.80	1.11	0.96	0.327
Beta-Blocker
Yes vs No	0.93	0.80	1.09	1.26	0.262
CCB
Yes vs No	0.95	0.80	1.13	0.57	0.450
Diuretic
Yes vs No	0.97	0.82	1.14	0.28	0.596

Notes: Analysis based on 5617 (3584 adherent and 2033 non-adherent) older adults with dementia and newly diagnosed major depression. Results are based on multiple logistic regression analysis. In terms of the density of neurologists and psychiatrists, the category 0 represents zero neurologists/psychiatrists in the zip-code and the categories 1, 2, and 3 represent the first, second, and third tertiles, respectively, of non-zero densities. Global Wald chi-square was significant, χ² ₍₃₅₎ = 91.543, p < 0.001. *Represents statistical significance (p-value<0.01).

Abbreviations: AOR, adjusted odds ratio; CI, confidence intervals; ACE inhibitors, angiotensin-converting enzyme inhibitors; ARBs, angiotensin receptor blockers; PPI, proton pump inhibitor; CCB, calcium channel blockers; ELX, Elixhauser.