School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America.
Health Policy & Management, UNC Gillings School of Global Public Health, Chapel Hill, North Carolina, United States of America.
BMC Public Health. 2020 Apr 28;20(1):567. doi: 10.1186/s12889-020-08585-w.
Adherence to antiretroviral therapy is critical to the achievement of the third target of the UNAIDS Fast-Track Initiative goals of 2020-2030. Reliable, valid and accurate measurement of adherence are important for correct assessment of adherence and in predicting the efficacy of ART. The Simplified Medication Adherence Questionnaire is a six-item scale which assesses the perception of persons living with HIV about their adherence to ART. Despite recent widespread use, its measurement properties have yet to be carefully documented beyond the original study in Spain. The objective of this paper was to conduct internal consistency reliability, concurrent validity and measurement invariance tests for the SMAQ.
HIV-positive women who were receiving ART services from 51 service providers in two sub-cities of Addis Ababa, Ethiopia completed the SMAQ in a HIV treatment referral network study between 2011 and 2012. Two cross-sections of 402 and 524 female patients of reproductive age, respectively, from the two sub-cities were randomly selected and interviewed at baseline and follow-up. We used Cronbach's coefficient alpha (α) to assess internal consistency reliability, Pearson product-moment correlation (r) to assess concurrent validity and multiple-group confirmatory factor analysis to analyze factorial structure and measurement invariance of the SMAQ.
All participants were female with a mean age of 33; median: 34 years; range 18-45 years. Cronbach's alphas for the six items of the SMAQ were 0.66, 0.68, 0.75 and 0.75 for T1 control, T1 intervention, T2 control, and T2 intervention groups, respectively. Pearson correlation coefficients were 0.78, 0.49, 0.52, 0.48, 0.76 and 0.80 for items 1 to 6, respectively, between T1 compared to T2. We found invariance for factor loadings, observed item intercepts and factor variances, also known as strong measurement invariance, when we compared latent adherence levels between and across patient-groups.
Our results show that the six-item SMAQ scale has adequate reliability and validity indices for this sample, in addition to being invariant across comparison groups. The findings of this study strengthen the evidence in support of the increasing use of SMAQ by interventionists and researchers to examine, pool and compare adherence scores across groups and time periods.
抗逆转录病毒疗法的依从性对于实现 2020-2030 年联合国艾滋病规划署快速通道倡议目标的第三个目标至关重要。可靠、有效和准确的依从性测量对于正确评估依从性和预测 ART 的疗效非常重要。简化用药依从性问卷是一个六项目量表，用于评估艾滋病毒感染者对其接受抗逆转录病毒治疗的依从性的看法。尽管最近广泛使用，但除了最初在西班牙进行的研究外，其测量特性尚未得到仔细记录。本文的目的是对 SMAQ 进行内部一致性信度、同时效度和测量不变性检验。
2011 年至 2012 年期间，埃塞俄比亚两个卫星城市的 51 个服务提供者为接受抗逆转录病毒治疗服务的艾滋病毒阳性妇女在一个艾滋病毒转介网络研究中完成了 SMAQ。从这两个卫星城市中随机抽取了两个分别为 402 名和 524 名育龄期女性的横断面，并在基线和随访时进行了访谈。我们使用 Cronbach 的 α 系数（α）评估内部一致性信度，使用 Pearson 积差相关系数（r）评估同时效度，使用多组验证性因素分析分析 SMAQ 的因子结构和测量不变性。
所有参与者均为女性，平均年龄为 33 岁；中位数为 34 岁；年龄范围为 18-45 岁。SMAQ 的六个项目的 Cronbach 的 α 值分别为 T1 对照组的 0.66、T1 干预组的 0.68、T2 对照组的 0.75 和 T2 干预组的 0.75。T1 与 T2 相比，项目 1 至 6 的 Pearson 相关系数分别为 0.78、0.49、0.52、0.48、0.76 和 0.80。当我们比较患者组之间和之间的潜在依从性水平时，我们发现因子负荷、观察到的项目截距和因子方差具有不变性，也称为强测量不变性。
我们的研究结果表明，六项目 SMAQ 量表在本样本中具有足够的可靠性和有效性指标，并且在比较组之间具有不变性。这项研究的结果加强了越来越多的干预者和研究人员使用 SMAQ 来检查、汇集和比较不同组和时间段内的依从性评分的证据。
