Kephart George, Skedgel Chris, Sketris Ingrid, Grootendorst Paul, Hoar John
Department of Community Health and Epidemiology, Dalhousie University, Halifax, NS, Canada.
Am J Manag Care. 2007 Jun;13(6 Pt 2):328-34.
To test the hypothesis that deductibles (copayment combined with annual limits on out-of-pocket payments) may reduce the effect of copayments on drug use for patients who expect to reach the annual limit, using as a natural experiment the introduction of copayments with an annual maximum to the seniors' drug plan in Nova Scotia.
An interrupted time-series design estimated effects of the introduction of and subsequent increase in drug copayments on the use (vs nonuse) of medications and on the mean daily quantity of use among users by patients' likelihood of exceeding the annual maximum copayment. Effects on the use of less essential medications (histamine(2)-receptor antagonists) and more essential medications (oral antihyperglycemic agents) were examined. methods: Data were drug claims for beneficiaries 65 years and older from April 1, 1989, through September 30, 1992. Regression models (applied to person-month data) estimated effects of the policies on the use and quantity of medication use.
Copayments ($3 per prescription and 20% of the prescription cost) were associated with reductions in the quantity of medication use, ranging from 5% to 15%, but only when the annual maximum copayment was unlikely to be reached. Introducing a 20% copayment increased the percentage who reached the annual maximum, decreasing the proportion of patients who reduced their drug use.
Although copayment policies are associated with reductions in the use of essential and less essential medications, annual limits on total copayments paid will limit copayment effects to patients who are unlikely to reach the annual maximum copayment.
检验如下假设，即免赔额（自付费用与年度自付费用上限相结合）可能会降低自付费用对预计达到年度上限的患者药物使用的影响，以新斯科舍省老年人药物计划引入年度最高自付费用作为一项自然实验。
一项中断时间序列设计，根据患者超过年度最高自付费用的可能性，估计引入药物自付费用及随后提高自付费用对药物使用（与未使用相对）以及使用者平均每日使用量的影响。研究了对使用必要性较低的药物（组胺2受体拮抗剂）和使用必要性较高的药物（口服降糖药）的影响。方法：数据为1989年4月1日至1992年9月30日65岁及以上受益人的药物报销申请。回归模型（应用于个人月度数据）估计了这些政策对药物使用和用量的影响。
自付费用（每张处方3加元及处方费用的20%）与药物使用量减少相关，减少幅度为5%至15%，但仅在不太可能达到年度最高自付费用时如此。引入20%的自付费用会增加达到年度最高费用的百分比，从而降低减少药物使用的患者比例。
虽然自付费用政策与使用必要性较高和较低的药物减少相关，但支付的总自付费用年度上限会将自付费用的影响限制在不太可能达到年度最高自付费用的患者身上。
