Patient knowledge on oral anticoagulants: results of a questionnaire survey in Germany and comparison with the literature.
OBJECTIVE
In order to use their drugs reliably, safely and correctly patients need to be well informed about their treatment, which applies in particular to critical dose drugs. The aim of this study was to investigate the patients' knowledge on anticoagulants, and to identify patient characteristics associated with low knowledge.


METHODS
Based on the Patient Information Leaflet, an 8-item multiple-choice test was developed, pre-tested and adapted. The final version was assessed in terms of readability and distributed to 59 anticoagulated medical inpatients of a German university hospital. The scoring range was 0 â 8 points (each correct answer giving 1 point).


RESULTS
The total knowledge level ranged between 12.5% and 87.5% (1/8 â 7/8 points) with an average of 55% (mean 4.4 A+/- 1.4 points). The topics most often answered not correctly included drug-drug and drug-food interactions. The statistical analysis of the association between knowledge on each topic and patient characteristic revealed a significant correlation between knowledge on drug-drug interactions and the patient's education (Mann--Whitney-U-test: p = 0.032) and age (r = -0.34; p = 0.015). There was no significant correlation between the total test score and any of the patient characteristics.


CONCLUSIONS
Healthcare professionals need to be aware that patients on oral anticoagulants may have significant knowledge gaps, particularly concerning drug-drug and drug-food interactions. In practice, the questionnaire, which was short, easy to read, and well accepted, might be used to identify the patients' knowledge and individual knowledge gaps in order to subsequently tailor information to their needs.
Jank
S
S
Department of Internal Medicine VI, Clinical Pharmacology and Pharmacoepidemiology, Heidelberg, Germany.
Bertsche
T
T
Herzog
W
W
Haefeli
W E
WE
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D004347:Drug Interactions; D004522:Educational Status; D005260:Female; D005858:Germany; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D010353:Patient Education as Topic / Q000379:methods; D011795:Surveys and Questionnaires; D014859:Warfarin / Q000627:therapeutic use*
D000925:Anticoagulants; D014859:Warfarin