Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, Durham, NC 27705, USA.
Med Care. 2012 Dec;50(12):1013-9. doi: 10.1097/MLR.0b013e318269e121.
Self-report measures of medication nonadherence confound the extent of and reasons for medication nonadherence. Each construct is assessed with a different type of psychometric model, which dictates how to establish reliability and validity.
To evaluate the psychometric properties of a self-report measure of medication nonadherence that assesses separately the extent of nonadherence and reasons for nonadherence.
Cross-sectional survey involving the new measure and comparison measures to establish convergent, discriminant, and predictive validity. The new measure was readministered 2-21 days later.
A total of 202 veterans with treated hypertension were recruited from the Durham Veterans Affairs Medical Center.
A new self-report measure assessed the extent of nonadherence and reasons for nonadherence. Comparison measures included self-reported medication self-efficacy, beliefs about medications, impression management, conscientiousness, habit strength, and an existing nonadherence measure.
Three items assessing the extent of nonadherence produced reliable scores for this sample, α = 0.84 (95% confidence interval, 0.80-0.87). Correlations with comparison measures provided evidence of convergent and discriminant validity. Correlations with systolic ( r = 0.27, P < 0.0001) and diastolic (r = 0.27, P < 0.0001) blood pressure provided evidence of predictive validity. Reasons for nonadherence were assessed with 21 independent items. Intraclass correlations were 0.58 for the extent score and ranged from 0.07 to 0.64 for the reasons.
The dual conceptualization of medication nonadherence allowed a stronger evaluation of the reliability and validity than was previously possible with measures that confounded these 2 constructs. Measurement of self-reported nonadherence consistent with psychometric principles will enable reliable, valid evaluation of interventions to reduce nonadherence.
自我报告的药物不依从性测量方法混淆了药物不依从性的程度和原因。每种结构都用不同类型的心理测量模型进行评估，这决定了如何建立可靠性和有效性。
评估一种自我报告的药物不依从性测量方法的心理测量特性，该方法分别评估不依从性的程度和原因。
涉及新措施和比较措施的横断面调查，以建立收敛、判别和预测有效性。新措施在 2-21 天后重新进行。
总共招募了 202 名来自达勒姆退伍军人事务医疗中心的接受治疗的高血压退伍军人。
一种新的自我报告措施评估了不依从的程度和不依从的原因。比较措施包括自我报告的药物自我效能、对药物的信念、印象管理、尽责性、习惯强度和现有的不依从性措施。
三个评估不依从程度的项目为该样本产生了可靠的分数，α=0.84（95%置信区间，0.80-0.87）。与比较措施的相关性提供了收敛性和判别有效性的证据。与收缩压（r=0.27，P<0.0001）和舒张压（r=0.27，P<0.0001）的相关性提供了预测有效性的证据。不依从的原因用 21 个独立的项目进行评估。程度得分的组内相关系数为 0.58，原因得分的范围为 0.07 至 0.64。
药物不依从性的双重概念化允许比以前使用混淆这两个结构的措施更有力地评估可靠性和有效性。符合心理测量原则的自我报告不依从性的测量将能够可靠、有效地评估减少不依从性的干预措施。
