Division of Pharmaceutical Outcomes and Policy, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill.
Department of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Med Care. 2021 Nov 1;59(11):997-1005. doi: 10.1097/MLR.0000000000001625.
Of 58 medication adherence group-based trajectory modeling (GBTM) published studies, 74% used binary and 26% used continuous GBTM. Few studies provided a rationale for this choice. No medication adherence studies have compared continuous and binary GBTM.
The objective of this study was to assess whether continuous versus binary GBTM: (1) impacts adherence trajectory shapes; and (2) results in the differential classification of patients into adherence groups.
Patients were prevalent statin users with myocardial infarction hospitalization, 66+ years old, and continuously enrolled in fee-for-service Medicare. Statin medication adherence was measured 6 months prehospitalization using administrative claims. Final GBTM specifications beyond default settings were selected using a previously defined standardized procedure and applied separately to continuous and binary (proportion of days covered ≥0.80) medication adherence measures. Assignment to adherence groups was compared between continuous and binary models using percent agreement of patient classification and the κ coefficient.
Among 113,296 prevalent statin users, 4 adherence groups were identified in both models. Three groups were consistent: persistently adherent, progressively nonadherent, and persistently nonadherent. The fourth continuous group was moderately adherent (progressively adherent in the binary model). When comparing patient assignment into adherence groups between continuous and binary trajectory models, only 78.4% of patients were categorized into comparable groups (κ=0.641; 95% confidence interval: 0.638-0.645). The agreement was highest in the persistently adherent group (∼94%).
Continuous and binary trajectory models are conceptually different measures of medication adherence. The choice between these approaches should be guided by study objectives and the role of medication adherence within the study-exposure, outcome, or confounder.
在 58 项基于药物依从性的轨迹建模（GBTM）已发表研究中，74%使用二进制，26%使用连续 GBTM。很少有研究为此选择提供理论依据。没有药物依从性研究比较过连续和二进制 GBTM。
本研究旨在评估连续与二进制 GBTM 是否存在以下差异：（1）对依从轨迹形状的影响；（2）对患者分类到不同依从组的结果。
患者为有心肌梗死住院史的老年（≥66 岁）持续性他汀类药物使用者，且连续参加了按服务收费的医疗保险。使用行政索赔数据测量患者在住院前 6 个月的他汀类药物依从性。采用先前定义的标准化程序选择超出默认设置的最终 GBTM 规范，并分别应用于连续和二进制（覆盖天数比例≥0.80）药物依从性测量值。通过患者分类的百分比一致性和 κ 系数比较连续和二进制模型对依从组的分配。
在 113296 名有他汀类药物使用史的患者中，两种模型均确定了 4 个依从组。其中 3 个组一致：持续依从、逐渐不依从和持续不依从。第四个连续组为中度依从（在二进制模型中为逐渐依从）。当比较连续和二进制轨迹模型中患者分配到依从组的情况时，只有 78.4%的患者被归入可比组（κ=0.641；95%置信区间：0.638-0.645）。在持续依从组中，一致性最高（接近 94%）。
连续和二进制轨迹模型是药物依从性的两种不同概念性度量方法。在选择这些方法时，应根据研究目标以及药物依从性在研究中的作用（暴露、结局或混杂因素）来指导。
