VALIDATION OF THE ADHERENCE BARRIERS QUESTIONNAIRE (ABQ) – AN INSTRUMENT FOR IDENTIFYING POTENTIAL RISK FACTORS ASSOCIATED WITH MEDICATION-RELATED NON-ADHERENCE

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VALIDATION OF THE ADHERENCE BARRIERS QUESTIONNAIRE (ABQ) – AN INSTRUMENT FOR IDENTIFYING POTENTIAL RISK FACTORS ASSOCIATED WITH MEDICATION-RELATED NON-ADHERENCE
Autor Sabrina Müller, Thomas Wilke
In: VALUE IN HEALTH
Ausgabe Vol. 17
ISBN/ISSN:
Erscheinungsjahr 2014
Jahrgang
Seitenzahl
Hyperlink http://www.valueinhealthjournal.com/issue/S1098-3015%2814%29X0007-0?page=21
Review

ABSTRACT


OBJECTIVES

Medication-related non-adherence is a major challenge in the real-life treatment of patients. To meet this challenge successfully, adherence interventions with a tailored approach towards patient-specific adherence barriers are needed. Therefore, a reliable and practicable questionnaire for identification of those adherence barriers in specific patients is needed. The aim of this investigation is to develop and validate such a questionnaire.

METHODS

The “Adherence Barriers Questionnaire (ABQ)” was developed and tested in 432 patients with atrial fibrillation in a multicenter observational cohort study. Evaluation of the questionnaire included an assessment of internal consistency as well as factor analysis. Criterion-related external validity was appraised by comparing the ABQ score with the score of a self-report adherence measure and with a clinical parameter (time in therapeutic range (TTR) regarding INR values in the VKA-based stroke prophylaxis treatment of patients).

RESULTS

The final 14-item ABQ scale demonstrated high internal consistency (Cronbach’s alpha=0.820). Factor analysis identified a three-factor solution, representing intentional adherence barriers with 5 items (31.9% of the variance), medication- or health care system-related adherence barriers with 5 items (13.3% of the variance) and unintentional adherence barriers with 4 items (7.7% of the variance).

The ABQ correlated significantly with self-reported non-adherence (Spearman’s rho=0.438, P<0.001) as well as TTR (Spearman’s rho=-0.161, P<0.01). Patients with above-average ABQ scores (increased number of existing adherence barriers) were significantly (p<0.005, Pearson Chi-Square) more likely to have a poor anticoagulation quality (TTR<60%) than patients with a lower ABQ score (44.6% versus 27.3%).

CONCLUSION

The ABQ is a practicable, reliable and valid instrument for identifying specific barriers to medication-related adherence. Future research is required to examine the ability of the ABQ to identify patient perception/behavior changes over time which may be important for the measurement of success of adherence interventions.