Watanabe Jonathan H, Kazerooni Rashid, Bounthavong Mark
Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Dr., #0714, La Jolla, CA 92093, USA.
J Manag Care Pharm. 2014 Jan;20(1):43-50. doi: 10.18553/jmcp.2014.20.1.43.
Statins remain a fundamental component of pharmacologic therapy for hyperlipidemia. Health benefits of statin therapy are jeopardized when adherence is reduced.
To (a) assess the association between copayment and copayment type on statin adherence using 2 different thresholds of adherence and (b) identify the incremental change in statin adherence associated with presence of copayment and copayment type.
We executed a retrospective cohort study of new users of statins with dyslipidemia from the Veterans Health Administration (VHA) within the Veterans Integrated Service Network 22 who initiated a statin between November 30, 2006, and December 2, 2007. We used exposure categories of Any Copayment versus No Copayment, indicating a patient had a copayment or had no copayment in order to obtain medications, respectively. As a separate analysis, we varied the exposures to the standard VHA copayment categories: (a) Service-Connected (SC) Copayment (patients with service-related injury), (b) Non-Service-Connected (NSC) Copayment (patients without a service-related injury), and (c) No Copayment. Using each set of exposures, we conducted separate multiple logistic regression analyses using 2 different adherence outcomes based on medication possession ratio (MPR) threshold: (1) adherence defined as MPR ≥ 0.8 and (2) adherence defined as MPR ≥ 0.9. We then proceeded with multiple linear regression models to determine the incremental change in MPR associated with the 2 sets of exposures. Subjects were required to be enrolled in VHA services for at least 2 years prior to index date and throughout the 1-year study period.
A total of 4,886 subjects were identified for analysis based on the inclusion and exclusion criteria. Patients who did not pay a copayment for their statin medications were more likely to have adherence rates of ≥ 0.8 MPR and ≥ 0.9 MPR relative to the No Copayment Group with odds ratios (OR) of 1.19 (95% CI = 1.03-1.37) and 1.28 (95% CI = 1.11-1.48), respectively. The second analysis applied the VHA exposure categories of SC Copayment, NSC Copayment, and No Copayment. Using the 0.8 MPR or greater adherence threshold, the No Copayment group was associated with an increased likelihood of adherence versus the SC Copayment category as reference group with an OR of 1.31 (95% CI = 1.10-1.58). The NSC Copayment was associated with a nonsignificant increase in odds of adherence at the 0.8 MPR level or greater with OR of 1.12 (95% CI = 0.98-1.39). Using the 0.9 MPR level or greater, adherence threshold findings were similar. The No Copayment group produced an OR of 1.42 (95% CI = 1.17-1.71) compared with the SC Copayment group. The NSC Copayment group was associated with a nonsignificant increase in odds of adherence at the 0.9 MPR level or greater with an OR of 1.12 (95% CI = 0.97-1.38).The No Copayment group was associated with an increase in MPR of 0.02 (95% CI = 0.002-0.035) versus the Any Copayment category. Using the VHA copayment categories, we observed an increase in MPR for the No Copayment group versus the SC Copayment group of 0.03 (95% CI = 0.01-0.05). The NSC Copayment group was associated with a nonsignificant increase in MPR versus the SC Copayment group of 0.02 (95% CI = -0.003-0.036).
Patients without out-of-pocket payments for their statins were more likely to adhere to therapy. Patients who pay a copayment for their statin medications were also compared with each other based on whether they (a) received any of their nonstatin prescriptions without a copayment or (b) paid a copayment on all of their prescriptions including statins. Our findings suggest that, among those that pay for their statins, patients are less adherent to their statins if other medications they are prescribed are copayment free. Thus, patient consumption behavior may be influenced by the relative cost of medications in patient prescription lists. Additional counseling on the necessity of adherence should be given to patients paying a copayment for their statin prescriptions.
他汀类药物仍然是高脂血症药物治疗的基本组成部分。当依从性降低时，他汀类药物治疗的健康益处会受到损害。
(a) 使用两种不同的依从性阈值评估自付费用和自付费用类型与他汀类药物依从性之间的关联，以及(b) 确定与自付费用和自付费用类型相关的他汀类药物依从性的增量变化。
我们对退伍军人综合服务网络22内退伍军人健康管理局（VHA）中血脂异常的他汀类药物新用户进行了一项回顾性队列研究，这些用户在2006年11月30日至2007年12月2日期间开始使用他汀类药物。我们使用了“有自付费用”与“无自付费用”的暴露类别，分别表示患者为获得药物有自付费用或无自付费用。作为一项单独的分析，我们将暴露情况改为VHA标准自付费用类别：(a) 与服役相关的自付费用（患有与服役相关损伤的患者），(b) 非与服役相关的自付费用（没有与服役相关损伤的患者），以及(c) 无自付费用。使用每组暴露情况，我们基于药物持有率（MPR）阈值，使用两种不同的依从性结果进行了单独的多因素逻辑回归分析：(1) 将依从性定义为MPR≥0.8，以及(2) 将依从性定义为MPR≥0.9。然后我们进行多因素线性回归模型，以确定与这两组暴露情况相关的MPR的增量变化。受试者在索引日期之前至少2年以及整个1年的研究期间都必须参加VHA服务。
根据纳入和排除标准，共确定了4886名受试者进行分析。相对于无自付费用组，他汀类药物无需自付费用的患者更有可能达到MPR≥0.8和MPR≥0.9的依从率，优势比（OR）分别为1.19（95%CI = 1.03 - 1.37）和1.28（95%CI = 1.11 - 1.48）。第二项分析应用了VHA的与服役相关的自付费用、非与服役相关的自付费用和无自付费用的暴露类别。使用MPR≥o.8的依从性阈值，以与服役相关的自付费用类别作为参照组，无自付费用组的依从可能性增加，OR为1.31（95%CI = 1.10 - 1.58）。在MPR≥0.8或更高水平时，非与服役相关的自付费用组的依从优势比非显著增加，OR为1.12（95%CI = 0.98 - 1.39）。使用MPR≥0.9水平或更高时，依从性阈值的结果相似。与与服役相关的自付费用组相比，无自付费用组的OR为1.42（95%CI = 1.17 - 1.71）。在MPR≥0.9水平或更高时，非与服役相关的自付费用组的依从优势比非显著增加，OR为1.12（95%CI = 0.97 - 1.38）。与任何自付费用类别相比，无自付费用组的MPR增加了0.02（95%CI = 0.002 - 0.035）。使用VHA自付费用类别，我们观察到无自付费用组相对于与服役相关的自付费用组的MPR增加了0.03（95%CI = 0.01 - 0.05）。与与服役相关的自付费用组相比，非与服役相关的自付费用组的MPR非显著增加了0.02（95%CI = -0.003 - 0.036）。
他汀类药物无需自掏腰包支付费用的患者更有可能坚持治疗。他汀类药物有自付费用的患者还根据以下情况进行了相互比较：(a) 他们是否有任何非他汀类处方无需自付费用，或者(b) 他们是否对包括他汀类药物在内的所有处方都支付了自付费用。我们的研究结果表明，在那些为他汀类药物付费的患者中，如果他们开具的其他药物无需自付费用，那么他们对他汀类药物的依从性就较低。因此，患者的消费行为可能会受到患者处方清单中药物相对成本的影响。对于为他汀类药物处方支付自付费用的患者，应给予关于坚持治疗必要性的额外咨询。
