Patient–doctor relationship and adherence to capecitabine in outpatients of a German comprehensive cancer center

Figures & data

Figure 1 Perceived burden of side effects on a visual analog scale (VAS, 0–100).

Table 1 Sociodemographic and medical characteristics of outpatients receiving capecitabine (n=64)

	Time	n	%
		64	100
Age, mean (SD; range)	66 years (12; 28–89)
Gender
Female		17	27
Male		47	73
Family status
Married		46	72
Not married		18	28
Education
Secondary school		41	64
Higher education		23	36
Tumor entity
Colorectal cancer		54	84
Stomach cancer		6	9
Breast cancer		2	3
Pancreatic cancer		1	2
Cancer of unknown origin		1	2
Tumor depth
T1		4	6
T2		14	22
T3		26	41
T4		18	28
TX		2	3
Lymph nodes
N neg		24	38
N pos		40	63
Metastasis
M neg		46	72
M pos		18	28
Regimen
Adjuvant		39	61
Palliative		25	39
Capecitabine
Monotherapy		42	66
Combined therapy		22	34
Time since tumor diagnosis, mean (SD; range)	19 months (34; 1–185)
Time since Cap treatment, mean (SD; range)	7 months (9; 1–50)

Abbreviations: N neg, no regional lymph node metastases; T1, tumor invades submucosa; N pos, metastasis to regional lymph nodes; T2, tumor invades muscularis propria; T3, tumor invades through the muscularis propria into the pericolorectal tissues; M neg, no distant metastasis; M pos, metastasis to distant organs; T4, tumor penetrates visceral peritoneum or invades to other organs or structures; TX, primary tumor cannot be assessed; Cap, capecitabine.

Figure 2 Participant satisfaction with information received (Satisfaction with Information about Medicines Scale, n=64).

Table 2 Correlations between adherence and sociodemographic and medical variables (n=64) using Mann–Whitney U-test

Variable	Median	IQR	Mean rank	Sum of ranks	U	Z	P-value
Age
Adherent	69 years	57–76	33.71	1,618.00	326.000	0.900	0.368
Non-adherent	65 years	54–73	28.88	462.00
Tumor depth (T1–T4)
Adherent	3	2–4	33.35	1,601.00	343.000	−0.670	0.503
Non-adherent	3	2–4	33.94	479.00
Time since tumor diagnosis
Adherent	7 m	4–16	32.43	1,556.50	380.500	−0.054	0.957
Non-adherent	9 m	3–13	32.72	523.50
Time since Cap treatment
Adherent	3 months	2–8	32.76	1,572.50	371.500	−0.195	0.845
Non-adherent	4 months	2–7	31.72	507.50
HFS
Adherent	37.5	2.5–80.0	33.42	1,604.00	340.000	−0.689	0.491
Non-adherent	27.5	1.3–63.8	29.76	476.00
Fatigue
Adherent	37.5	20–67.5	34.61	1,661.50	282.500	−1.581	0.114
Non-adherent	22.5	0–50	26.16	418.50
Diarrhea
Adherent	7	0–28.8	31.93	1,598.50	356.500	−0.446	0.656
Non-adherent	5	0–50	34.22	547.50
Mucositis
Adherent	5	0–20	32.25	1,548.00	372.000	−0.197	0.844
Non-adherent	2.5	0–40	32.25	532.00
Nausea
Adherent	5	0–30	33.30	1,598.50	345.500	−0.632	0.528
Non-adherent	2.5	0–15	30.09	481.50
Vomiting
Adherent	0	0–5	31.88	1,498.50	370.500	−0.109	0.913
Non-adherent	0	0–5	32.34	517.50
Fever
Adherent	0	0–0	32.67	1,568.00	376.500	−0.577	0.564
Non-adherent	0	0–0	32.00	512.00

Abbreviations: Cap, capecitabine; IQR, interquartile range; U, Mann–Whitney U-test; Z, Kolmogorov–Smirnov Z; HFS, hand-foot syndrome.

Table 3 Correlations between adherence and sociodemographic and medical variables (n=64) using Fishers exact test

Variable	n	OR	95% CI	P-value
Gender				1.000
Male
Adherent	35	1.029	0.739–1.433
Non-adherent	12
Female
Adherent	13	0.923	0.351–2.429
Non-adherent	4
Family status				0.756
Married
Adherent	35	0.943	0.650–1.369
Non-adherent	11
Not married
Adherent	13	1.154	0.487–2.733
Non-adherent	5
Lymph nodes				0.866
Positive
Adherent	25	0.980	0.710–1.560
Non-adherent	10
Negative
Adherent	23	1.300	0.367–2.489
Non-adherent	6
Metastasis				0.756
Positive
Adherent	5	1.154	0.487–2.733
Non-adherent	13
Negative
Adherent	35	0.943	0.650–1.369
Non-adherent	11
Regimen				0.561
Adjuvant
Adherent	28	1.179	0.784–1.772
Non-adherent	11
Palliative
Adherent	20	0.750	0.337–1.669
Non-adherent	5
Capecitabine				1.000
Monotherapy
Adherent	31	1.065	0.720–1.574
Non-adherent	11
Combination therapy
Adherent	17	0.882	0.388–2.006
Non-adherent	5

Table 4 Logistic regression model on adherence with sum scores as predictors. Nagelkerke’s R².291

	B	SE	P-value	OR	95% CI
Adherence
Predictor variables
BMQ sum score	0.237	0.077	0.002	1.268	1.090–1.475
SIMS sum score	0.224	0.110	0.040	1.252	1.010–1.551
PDRQ sum score	−0.089	0.064	0.162	0.915	0.808–1.036
Constant	−5.810	3.138	0.064	0.003

Abbreviations: B, intercept; SE, standard error; BMQ, Beliefs about Medicines Questionnaire; SIMS, Satisfaction with Information about Medicines Scale; PDRQ, Patient–Doctor Relationship Questionnaire.

Table 5 Logistic regression model on adherence with subscores as predictors. Nagelkerke’s R².309

	B	SE	P-value	OR	95% CI
Adherence
Predictor variables
BMQ subscore necessity	0.130	0.084	0.120	1.139	0.967–1.343
BMQ subscore concerns	0.318	0.108	0.003	1.374	1.112–1.699
SIMS subscore	0.165	0.207	0.426	1.179	0.768–1.770
Action and usage
SIMS subscore	0.301	0.182	0.097	1.352	0.947–1.930
Potential problems
Constant	−8.428	3.239	0.009	0.000

Abbreviations: B, intercept; SE, standard error; BMQ, Beliefs about Medicines Questionnaire; SIMS, Satisfaction with Information about Medicines Scale.

Figure S1 Participant satisfaction with Patient–Doctor relationship (PDRQ-9, n=64).

Figure S2 Participant reported necessities of capecitabine therapy (Beliefs about Medicines Questionnaire – Necessity Scale, n=64).

Figure S3 Participant reported concerns of capecitabine therapy (Beliefs about Medicines Questionnaire – Concerns Scale, n=64).

Table S1 Single items of the Patient–Doctor Relationship Questionnaire (PDRQ-9, n=64)

	Totally appropriate		Mostly appropriate		Appropriate		Somewhat appropriate		Not at all appropriate*		Item score
	N	%	N	%	N	%	N	%	N	%	M	SD
My physician is dedicated to help me	43	67.2	16	25	5	7.8					4.59	0.64
I can talk to my physician	40	62.5	18	28.1	5	7.8	1	1.6			4.52	0.71
I find my physician easily accessible	40	62.5	18	28.1	5	7.8	1	1.6			4.50	0.78
I feel content with my physician’s treatment	37	57.8	22	34.4	4	6.3	1	1.6			4.48	0.69
My physician helps me	38	59.4	20	31.3	5	7.8	1	1.6			4.48	0.71
I trust my physician	37	57.8	19	29.7	8	12.5					4.45	0.71
My physician understands me	33	51.6	21	32.8	9	14.1	1	1.6			4.34	0.78
My physician and I agree on the nature of my medical symptoms	28	43.8	28	43.8	7	10.9	1	1.6			4.30	0.73
My physician has enough time for me	28	43.8	24	37.5	8	12.5	4	6.3			4.19	0.89
Total mean											4.43	0.64

Note:

* No patients ticked this column.

Table S2 Self-reported adherence to capecitabine (n=64)

MARS statements	Number (%) of statements
	Always	Often	Sometimes	Rarely	Never
I forget to take it	0	0	2 (3)	5 (8)	57 (89)
I alter the dose	0	0	2 (3)	2 (3)	60 (94)
I stop taking it for a while	1 (2)	0	0	2 (3)	61 (95)
I decide to miss out a dose	1 (2)	0	1 (2)	0	62 (97)
I take less than instructed	0	0	2 (3)	1 (2)	61 (95)

Notes: 13 participants were non-adherent according to Medication Adherence Report Scale (MARS). Some participants stated multiple methods of deviation.