Knowledge About Immunosuppressant Medication and Its Correlates in a German Kidney Transplant Population – Results of a KTx360° Substudy

Figures & data

Table 1 Patient Characteristics

Patient Characteristics	N=702
Age in years
Mean (SD)	52.4 (14.2)
Median (IQR)	54.6 (20.0)
Female sex, n (%)	294 (41.9)
≥12 years school attendance, n (%), (n=697)	183 (26.1)
Living in a partnership, n (%), (n=697)	464 (66.6)
German as first language, n (%), (n=641)	572 (81.5)
Living donation, n (%)	207 (29.5)
Time on dialysis in months
Mean (SD)	61.1 (49.7)
Median (IQR)	55.5 (84)
Time since transplantation in months
Mean (SD)	65.1 (69.2)
Median (IQR)	48.6 (78.2)
eGFR (mL/min/1.73 m^2) at time of assessment (n=693)
Mean (SD)	45.8 (18.7)
Median (IQR)	43.1 (24.4)
Diabetes mellitus, n (%)	123 (17.5)
Hypertension, n (%)	595 (84.8)
Coronary heart disease, n (%)	79 (11.3)
HADS-D, Anxiety score (n=686)
Mean (SD)	5.1 (3.9)
Median (IQR)	4.0 (6.0)
HADS-D, Depression score (n=688)
Mean (SD)	4.3 (3.9)
Median (IQR)	3.0 (6.0)
F-SozU K7 score (n=687)
Mean (SD)	30.0 (6.0)
Median (IQR)	32.0 (8.0)
MARS-D score (n=687)
Mean (SD)	24.4 (1.2)
Median (IQR)	25.0 (1.0)
Knowledge test %
Mean (SD)	70.9 (18.0)
Median (IQR)	75.0 (25.0)

Abbreviations: eGFR, estimated glomerular filtration rate; F-SozU K7, Questionnaire for Perceived Social Support; HADS-D, Hospital Anxiety and Depression Scale; IQR, interquartile range; MARS-D, Medication Adherence Report Scale; SD, standard deviation.

Table 2 % of Patients Answering Each Item on the Immunosuppressant Knowledge Questionnaire (Correct Answers are Highlighted). Multiple Selections Were Allowed.

Question	% of Patients Choosing the Answer	% of Patients who Answered the Question Correctly*
1) Which of the following foods/beverages can influence your immunosuppressant blood levels?		80.2%
Kiwi	4.0%
Grapefruit	91.6%
Chocolate	4.6%
Coffee	5.3%
Pomegranate	26.8%
St. John’s wort	53.7%
Banana	7.5%
Peppermint tea	1.4%
2) When are immunosuppressant blood levels measured?		92.2%
Before intake	93.7%
During intake	0.7%
After intake	4.3%
Independent of intake	1.7%
3) When should you take your immunosuppressants in relation to meals?		54.3%
1–2 h before meals	43.4%
Directly before meals	13.5%
During meals	16.0%
1–2 h after meals	34.9%
More than 2 hours after meals	9.1%
4) Which action should be taken when you forgot to take one dosage of your immunosuppressant?		80.8%
Skip the dosage completely	44.3%
Quickly take the medication	49.6%
Take twice the dosage	0.3%
Measure blood level and decide afterward	13.2%
5) Which action should be taken if you- after having taken your immunosuppressant- experience diarrhea or vomiting during the day?		55.3%
Continue immunosuppressant intake as before	66.7%
Immediately take another dosage	0.1%
Take twice the dosage the next time	0.9%
Measure blood level and decide afterward	37.0%
6) Diarrhea can significantly alter cyclosporine or tacrolimus blood levels.		78.5%
Yes	78.5%
No	11.3%
7) While traveling immunosuppressants have to be stored in the suitcase rather than carry-on-luggage in order to maintain a cooler temperature.		64.5%
Yes	28.3%
No	65.0%
8) Switching between immunosuppressants from different manufactures (generics) is unproblematic.		61.5%
Yes	28.8%
No	62.3%

Note: *Questions were judged to be answered correctly if patients chose at least one correct answer without choosing a wrong answer at the same time.

Table 3 Correlational Analyses of the Knowledge Test Score Using Spearman Correlations

	Knowledge Test (% of Correctly Answered Questions)
Age (years)	r=0.015, p=0.70
time since transplantation (months)	r=−0.036, p=0.34
eGFR (mL/min/1.73 m^2)	r=0.047, p=0.22
HADS-D, Anxiety score (n=685)	r=−0.011, p=0.77
HADS-D, Depression score (n=687)	r=−0.062, p=0.11
F-SozU K7 score (n=686)	r=0.031, p=0.42
MARS score (n=686)	r=−0.021, p=0.58
Time on dialysis (n=690)	r=−0.074, p=0.051

Abbreviations: eGFR, estimated glomerular filtration rate; F-Sozu K7, Questionnaire for Perceived Social Support; HADS-D, Hospital Anxiety and Depression Scale; MARS-D, Medication Adherence Report Scale.

Table 4 Comparison of Knowledge Test Scores Between Dichotomous Variables

		Knowledge Test (% of Correctly Answered Questions)
	N	Mean (SD)	Statistics U-Tests
Sex
Female	294	72.4 (18.8)	Z=−2.000, p=0.036, η^2=0.006
Male	408	69.8 (17.4)
Partnership status
In a partnership	464	72.2 (17.4)	Z=−2.330, p=0.02, η^2=0.007
No partnership	233	68.6 (19.0)
Educational level
≥12 years	183	71.1 (17.1)	Z=−0.162, p=0.87
<12 years	514	71.0 (18.3)
Type of donation
Living donor	207	72.5 (17.7)	Z=−1.333, p=0.18
Deceased donor	495	70.3 (18.2)
Cognitive impairment
DemTect ≥13	559	72.0 (17.0)	Z=−2.160, p=0.03, η^2=0.007
DemTect <13	105	66.7 (21.1)
First language
German	572	71.7 (17.2)	Z=−2.744, p=0.006, η^2=0.011
Other	69	63.9 (22.8)

Table 5 Linear Regression Analysis

Variables	N	β	T	p-value	R^2
Knowledge test	583				0.048
Sex		−0.086	−2.083	p=0.038
First language		−0.113	−2.760	p=0.006
Partnership status		0.113	2.749	p=0.006
Cognitive impairment		−0.064	−1.545	p=0.123
Depression (HADS-D)		−0.049	−1.195	p=0.233
Time on dialysis (months)		−0.075	−1.831	p=0.068

Abbreviation: HADS-D, Hospital Anxiety and Depression Scale.