Testing the psychometric properties of the Medication Adherence Scale in patients with heart failure.
OBJECTIVE
Many factors may contribute to medication nonadherence in heart failure (HF), but no standard measure exists to evaluate factors associated with nonadherence. To fill this gap, we developed the Medication Adherence Scale (MAS) and tested its reliability and validity in patients with HF.


METHODS
Questionnaire data were collected from 100 patients with HF at baseline using the MAS, and objective adherence data were collected for 3 consecutive months using the Medication Event Monitoring System.


RESULTS
Principal component analysis yielded three factors that explained 63% of the variance in medication adherence: knowledge, attitudes, and barriers to medication adherence. Cronbach's alphas for these subscales ranged from .75 to .94, which supported their internal consistency. The Spearman rho correlation coefficients between the Medication Event Monitoring System and Knowledge, Attitudes, and Barriers scores were .25 to .31 (P < .05), demonstrating support for construct validity.


CONCLUSIONS
These results support the reliability and validity of the MAS as a measure of knowledge, attitudes, and barriers of medication adherence.
Wu
Jia-Rong
JR
University of Kentucky, College of Nursing, Lexington, KY 40536-0232, USA.
Chung
Misook
M
Lennie
Terry A
TA
Hall
Lynne A
LA
Moser
Debra K
DK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003144:Communication Barriers; D016903:Drug Monitoring / Q000295:instrumentation; D004522:Educational Status; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011446:Prospective Studies; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
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