Center for Organization, Leadership and Management Research, VA Boston, Boston, MA, USA.
J Gen Intern Med. 2013 Jul;28(7):876-85. doi: 10.1007/s11606-013-2342-3. Epub 2013 Feb 13.
Although the Medicare Part D coverage gap phase-out should reduce cost-related nonadherence (CRN) among seniors with diabetes, preferential generic prescribing may have already decreased CRN, while smaller numbers of patients using more costly branded oral anti-diabetic (OAD) medications remain vulnerable to CRN.
To estimate the effects of cost sharing in the Part D standard (non-LIS) benefit on adherence to different OAD classes, comparing two classes dominated by inexpensive generic medications and two by more costly branded medications.
Retrospective cohort study using dispensed prescription data for elderly non-LIS (N=81,047) and LIS (low-income subsidy) (N=150,359) beneficiaries using same class OAD(s) in 2008 and 2009. Logistic regression modeled non-LIS likelihood; LIS and non-LIS patients matched using propensity outcome (N=38,054). Logistic regression, controlling for demographic and health status characteristics, modeled effects of non-LIS coverage on 2009 OAD class adherence.
Main outcome measures were within-class OAD coverage year adherence, with patients considered adherent when days supplied to calendar days ratio at least 0.8.
Non-LIS patients had 0.52 and 0.57 times the odds of branded-only DPP-4 Inhibitor (N=1,812; 95 % CI: 0.43, 0.63; P<0.001) and Thiazolidinedione (TZD) (N=6,290; 95 % CI: 0.52, 0.63; P<0.001) adherence. Most patients (N=32,510; 82 %) used OADs in primarily generic classes, where we found no significant (Biguanides; N=21,377) or small differences (Sulfonylureas/Glinides [N=19,240; OR: 0.91; 95 % CI: 0.86, 0.97; P=0.002]) in adherence odds. Crude adherence rates were sub-optimal when CRN was not a factor (Non-LIS/LIS: Biguanides: 65 %/65 %; Sulfonylureas/Glinides: 66 %/68 %; LIS: DPP-4 Inhibitors: 66 %; TZDs: 67 %).
Gap elimination would not affect generic, but should reduce branded OAD CRN. Branded copayments may continue to lead to CRN. Policy initiatives and benefit changes targeting both cost deterrents for patients with more complex disease and non-cost generic OAD underuse are recommended.
尽管医疗保险部分 D 覆盖缺口阶段的结束应该会降低糖尿病老年患者的与费用相关的不依从性（CRN），但优先开仿制药可能已经降低了 CRN，而使用更昂贵的品牌口服抗糖尿病药物（OAD）的患者数量较少，仍然容易受到 CRN 的影响。
评估部分 D 标准（非 LIS）福利中的费用分担对不同 OAD 类别的依从性的影响，比较两种主要由廉价仿制药组成的 OAD 类别的依从性和两种主要由更昂贵的品牌药物组成的 OAD 类别的依从性。
使用 2008 年和 2009 年非 LIS（N=81,047）和 LIS（低收入补贴）（N=150,359）受益人的配药处方数据，进行回顾性队列研究。使用相同 OAD 类别（N=38,054）的逻辑回归模型，对非 LIS 可能性进行建模；使用倾向得分对 LIS 和非 LIS 患者进行匹配。控制人口统计学和健康状况特征后，逻辑回归模型对非 LIS 覆盖对 2009 年 OAD 类别的依从性的影响进行建模。
主要结局指标是类内 OAD 覆盖年度的依从性，当供应天数与日历天数的比率至少为 0.8 时，患者被认为是依从的。
非 LIS 患者使用 DPP-4 抑制剂（N=1,812；95%CI：0.43，0.63；P<0.001）和噻唑烷二酮（TZD）（N=6,290；95%CI：0.52，0.63；P<0.001）的品牌 OAD 的可能性是品牌 OAD 患者的 0.52 倍和 0.57 倍。大多数患者（N=32,510；82%）使用的 OAD 主要为仿制药，在这些药物中，我们没有发现显著（二甲双胍；N=21,377）或较小的差异（磺酰脲类药物/格列奈类药物[N=19,240；OR：0.91；95%CI：0.86，0.97；P=0.002]）。当不考虑 CRN 因素时，粗依从率不理想（非 LIS/LIS：二甲双胍：65%/65%；磺酰脲类药物/格列奈类药物：66%/68%；LIS：DPP-4 抑制剂：66%；TZD：67%）。
缺口消除不会影响仿制药，但应该会降低品牌 OAD 的 CRN。品牌共付额可能会继续导致 CRN。建议采取政策举措和福利变更，针对更复杂疾病的患者的费用抑制因素和非成本仿制药 OAD 的使用不足。
