Schneeweiss Sebastian, Soumerai Stephen B, Glynn Robert J, Maclure Malcolm, Dormuth Colin, Walker Alexander M
Department of Epidemiology, Harvard School of Public Health, Boston, Mass., USA.
CMAJ. 2002 Mar 19;166(6):737-45.
Increasing copayments for higher-priced prescription medications has been suggested as a means to help finance drug coverage for elderly patients, but evaluations of the impact of such policies are rare. The objective of this study was to analyze the effect of reference-based pricing of angiotensin-converting enzyme (ACE) inhibitors on drug utilization, cost savings and potential substitution with other medication classes.
We analyzed 36 months of claims data from British Columbia for 2 years before and 1 year after implementation of reference-based pricing (in January 1997). The 119,074 patients were community-living Pharmacare beneficiaries 65 years of age or older who used ACE inhibitors during the study period. The main outcomes were changes over time in use of ACE inhibitors, use of antihypertensive drugs and expenditures for antihypertensive drugs, as well as predictors of medication switching related to reference-based pricing.
We observed a sharp decline (29%) in the use of higher-priced cost-shared ACE inhibitors immediately after implementation of the policy (p < 0.001). After a transition period, the post-implementation utilization rate for all ACE inhibitors was 11% lower than projected from pre-implementation data. However, overall utilization of antihypertensives was unchanged (p = 0.40). The policy saved $6.7 million in pharmaceutical expenditures during its first 12 months. Patients with heart failure or diabetes mellitus who were taking a cost-shared ACE inhibitor were more likely to remain on the same medication after implementation of reference-based pricing (OR 1.12 [95% confidence interval, CI, 1.06-1.19] and 1.28 [95% CI 1.20-1.36] respectively). Patients with low-income status were more likely than those with high-income status to stop all antihypertensive therapy (OR 1.65 [95% CI 1.43-1.89]), which reflects a general trend toward discontinuation of therapy among these patients even before implementation of reference-based pricing.
Reference-based pricing in British Columbia achieved a sustained reduction in drug expenditures, and no changes in overall use of antihypertensive therapy were observed. Further research is needed on the overall health and economic effects of such policies.
提高高价处方药的自付费用被认为是帮助为老年患者的药物保险提供资金的一种方式，但对此类政策影响的评估却很少见。本研究的目的是分析基于参考定价的血管紧张素转换酶（ACE）抑制剂对药物使用、成本节约以及与其他药物类别潜在替代的影响。
我们分析了不列颠哥伦比亚省在基于参考定价实施前2年和实施后1年（1997年1月）的36个月索赔数据。这119,074名患者是65岁及以上的社区居住药物保险受益人，他们在研究期间使用了ACE抑制剂主要结果是ACE抑制剂使用、抗高血压药物使用和抗高血压药物支出随时间的变化，以及与基于参考定价相关的药物转换预测因素。
我们观察到政策实施后，高价成本分摊ACE抑制剂的使用立即大幅下降（29%）（p<0.001）。经过一个过渡期后，所有ACE抑制剂实施后的利用率比实施前数据预测的低11%。然而，抗高血压药物的总体使用情况没有变化（p=0.40）该政策在其实施的前12个月节省了670万美元的药品支出。在实施基于参考定价后，正在服用成本分摊ACE抑制剂的心力衰竭或糖尿病患者更有可能继续使用同一种药物（分别为OR 1.12[95%置信区间，CI，1.06 - 1.19]和1.28[95%CI 1.20 - 1.36]）。低收入患者比高收入患者更有可能停止所有抗高血压治疗（OR 1.65[95%CI 1.43 - 1.89]），这反映了即使在实施基于参考定价之前，这些患者中就存在的停药总体趋势。
不列颠哥伦比亚省的基于参考定价实现了药品支出的持续减少，并且未观察到抗高血压治疗总体使用情况的变化。需要对这类政策的整体健康和经济影响进行进一步研究。
