Adherence and patients’ experiences with the use of oral anticancer agents

Figures & data

Figure 1. Flow chart of patients and exclusions used to obtain the Study Population and Subpopulations A and AA.

Table I. Characteristics of study population and subpopulations A and AA.

	Study population N = 216		Subpopulation A: with adherence rate N = 177		Subpopulation AA: with adherence rate and on treatment N = 111
Characteristics	N	%	N	%	N	%
Age, years
Mean	58.5		58.5		57.8
Range	22–86		22–86		22–80
Sex
Male	120	55.6	100	56.5	63	56.8
Female	96	44.4	77	43.5	48	43.2
Hospital
VUmc	55	25.5	45	25.4	31	27.9
LUMC	36	16.7	28	15.8	17	15.3
St Radboud	98	45.4	83	46.9	46	41.4
UMCG	27	12.5	21	11.9	17	15.3
Cancer type
Solid tumor	143	66.2	121	68.4	65	58.6
Hematological malign	72	33.5	56	31.6	46	41.4
Unknown	1	0.5
Oral anticancer agent*
Capecitabine	75	34.7	64	36.2	26	23.4
Dasatinib	8	3.7	5	2.8	4	3.6
Erlotinib	5	2.3	3	1.7	3	2.7
Imatinib	31	14.4	26	14.7	23	20.7
Lenalidomide	33	15.3	27	15.3	19	17.1
Nilotinib	5	2.3	5	2.8	5	4.5
Sunitinib	23	10.6	17	9.6	10	9.0
Temozolomide	25	11.6	23	13.0	14	12.6
Thalidomide	11	5.1	7	4.0	7	6.3
Use status
On Treatment	135	62.5	111	62.7	111	100.0
Off Treatment	81	37.5	66	36.3	0	0
Duration of use (days)
Mean	373		375		408
Range	26–3221		26–3221		26–3221
	Duration of use (days) in subpopulation A (N = 177)
	N	Mean ± SD		median	range
All agents*	176	374.6 ± 511.7		197	26–3221
Capecitabine	64	206.4 ± 191.5		154	28–1068
Dasatinib	5	606.0 ± 257.3		689	272–931
Erlotinib	3	391.3 ± 545.2		130	26–1018
Imatinib	26	949.2 ± 994.8		500	60–3221
Lenalidomide	26	291.8 ± 240.8		214	70–993
Nilotinib	5	153.0 ± 77.5		122	74–277
Sunitinib	17	505.1 ± 415.2		364	69–1594
Temozolomide	23	265.4 ± 265.6		256	35–1081
Thalidomide	7	142.4 ± 99.5		94	60–305

*No users of everolimus, gefitinib, lapatinib or sorafenib participated.

Table II. Adherence.

	Subpopulation A: with adherence rate N = 177		Subpopulation AA: with adherence rate and on treatment N = 111
	N	%	N	%
Adherence
Mean± SD	99.1 ± 5.4		99.0 ± 5.4
Range	80.4–121.4		81.4–120.8
Adherence rate
< 80	0	0	0	0
≥ 80–< 90	11	6.2	7	6.3
≥ 90–< 95	12	6.8	9	8.1
≥ 95–< 100	45	25.4	31	27.9
100	61	34.5	31	27.9
> 100–≤ 105	35	19.8	24	21.6
> 105–≤ 110	10	5.6	8	7.2
> 110–≤ 120	1	0.6	0	–
> 120	2	1.1	1	0.9
Adherence ≥ 95–≤ 105%
Optimal	141	79.7	86	77.5
Sub-optimal	36	20.3	25	22.5
Adherence ≥ 90–≤ 110%
Optimal	163	92.1	103	92.8
Sub-optimal	14	7.9	8	7.2
Adherence rate		mean		range
Capecitabine	64	98.8		80.4–109.7
Dasatinib	5	93.7		84.9–100.5
Erlotinib	3	91.3		85.2–98.5
Imatinib	26	98.7		81.4–121.4
Lenalidomide	27	99.6		88.0–108.3
Nilotinib	5	99.4		98.4–101.3
Sunitinib	17	101.8		96.3–111.4
Temozolomide	23	99.98		91.8–106.8
Thalidomide	7	98.1		81.4–107.7

SD, standard deviation.

Table III. Univariate analysis of variables associated with optimal adherence (≥ 95%, ≥ 105%).

	Subpopulation A: with adherence rate N = 177				Subpopulation AA: with adherence rate and on treatment N = 111
	N	OR	95% CI	p-value	N	OR	95% CI	p-value
Sex (male gender)	177	0.63	0.30–1.30	0.211	111	0.63	0.26–1.55	0.317
Age	177	1.01	0.98–1.04	0.683	111	1.00	0.97–1.04	0.953
High education	173	2.79	1.22–6.37	0.015*	109	2.45	0.93–6.48	0.071
Not living alone	173	3.51	1.52–8.09	0.003*	109	8.77	3.01–25.58	< 0.001*
Paid work	173	0.91	0.39–2.14	0.837	109	0.86	0.31–2.34	0.763
Hematological cancer type	177	0.37	0.17–0.78	0.009*	111	0.38	0.15–0.94	0.036*
Cyclic dosing regimen	177	6.03	2.75–13.26	< 0.001*	111	9.23	3.13–27.25	< 0.001*
Duration of use	176	1.00	1.00–1.00	0.537	111	1.00	1.00–1.00	0.990
SIMS	172	1.00	0.98–1.02	0.898	108	1.03	0.95–1.12	0.435
BMQ
General overuse	170	0.92	0.81–1.05	0.215	107	0.89	0.76–1.04	0.145
General harm	172	0.89	0.77–1.03	0.129	108	0.89	0.74–1.06	0.191
Specific necessity	171	0.91	0.81–1.00	0.049*	107	0.90	0.79–1.02	0.086
Specific concern	170	0.97	0.88–1.07	0.523	107	0.96	0.85–1.08	0.459
Nec-conc differential	169	0.97	0.90–1.04	0.335	106	0.96	0.89–1.05	0.392
IPQ
Consequences	169	1.10	0.94–1.28	0.235	107	1.10	0.92–1.33	0.289
Time line	166	1.04	0.93–1.18	0.486	105	0.98	0.81–1.19	0.844
Personal control	168	0.96	0.85–1.08	0.476	106	0.92	0.80–1.06	0.237
Treatment control	170	0.78	0.63–0.96	0.018*	107	0.85	0.65–1.12	0.246
Identity	170	1.10	0.98–1.25	0.118	107	1.08	0.94–1.26	0.283
Concern	171	1.03	0.89–1.18	0.698	108	1.12	0.95–1.33	0.175
Coherence	169	0.94	0.83–1.06	0.287	107	0.91	0.77–1.07	0.254
Emotional response	171	1.03	0.90–1.17	0.687	108	1.05	0.90–1.22	0.537
Patient reported side effects
Fatigue					106	1.27	0.81–1.99	0.292
Hand foot syndrome					106	1.63	1.01–2.62	0.045*
Skin reactions					103	1.14	0.76–1.71	0.538
Diarrhea					105	1.24	0.74–2.06	0.414
Nausea					106	1.23	0.69–2.17	0.486
Stomach ache					105	1.59	0.74–3.40	0.234
Constipation					103	1.31	0.79–2.18	0.294
Infection					105	0.93	0.51–1.70	0.804
Headache					105	0.78	0.40–1.52	0.469
Muscle joint pain					104	1.17	0.76–1.81	0.486
Edema					104	0.64	0.44–0.94	0.024*
Mucositis					105	1.59	0.53–4.79	0.409
Weight loss					106	0.94	0.50–1.76	0.836
Cough					104	0.68	0.40–1.13	0.134
MARS
MARS total score					105	2.15	0.95–4.85	0.067
MARS (25 vs. < 25)					105	4.44	1.52–12.96	0.006*
EORTC QLQ-30
Global health status					109	0.98	0.96–1.01	0.108
Functional scales
Physical functioning					108	1.01	0.98–1.03	0.624
Role functioning					108	1.00	0.98–1.01	0.027*
Emotional functioning					109	1.00	0.98–1.03	0.713
Cognitive functioning					109	1.01	0.99–1.03	0.357
Social functioning					109	0.99	0.97–1.01	0.215
Symptom scales
Fatigue					108	1.00	0.98–1.02	1.000
Nausea and vomiting					109	0.97	0.92–1.01	0.132
Pain					109	0.99	0.96–1.01	0.235
Dyspnea					109	1.01	0.99–1.02	0.607
Insomnia					109	1.02	1.00–1.03	0.061
Appetite loss					109	1.00	0.98–1.02	0.850
Constipation					109	0.99	0.97–1.01	0.483
Diarrhea					108	1.01	0.99–1.02	0.590
Financial difficulties					108	0.99	0.97–1.01	0.195

BMQ, Beliefs about Medicines Questionnaire; CI, confidence interval; EORTC QLQ-C30, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30; IPQ, Illness Perception Questionnaire; MARS, Medication Adherence Rating Scale; OR, odds ratio; SIMS, satisfaction with Information about Medicines Scale. *significance (p ≤ 0.05).

Table IV. Multivariate analysis of variables associated with optimal adherence (≥ 95%, ≤ 105%).

	Subpopulation A: with adherence rate
N = 168	OR	95% CI	p-value
Cyclic dosing regimen	4.88	2.02–11.77	< 0.001*
Not living alone	4.59	1.68–12.52	0.003*
IPQ treatment control	0.77	0.61–0.98	0.036*
High education	2.53	1.00–6.41	0.050
	Subpopulation AA: with adherence rate and on treatment
N = 105	OR	95% CI	p–value
Cyclic dosing regimen	21.10	4.46–99.88	< 0.001*
Not living alone	20.69	4.06–105.43	< 0.001*

CI, confidence interval; IPQ, Illness Perception Questionnaire; OR, odds ratio. *significance (p ≤ 0.05).

Table V. Questionnaire on discontinuation.

(N = 79)	N	%
Reasons for discontinuation*
Side effects	27	34.2
Lack of efficacy	11	13.9
Scheduled	34	43.0
Other	22	27.8
Initiative for discontinuation
Patient	6	7.6
Physician	70	88.6
Partner/family	1	1.3
Other	2	2.5
Experience
Positive	27	34.6
Neutral	30	38.5
Negative	21	26.9
Don’t know	1

*more than one reason possible.