Leslie Douglas L, Rosenheck Robert A
Medical University of South Carolina, 151 Rutledge Ave., Bldg B, PO Box 250961, Charleston, SC 29425, USA.
J Ment Health Policy Econ. 2008 Sep;11(3):107-12.
It is unknown to what extent providers utilize the full range of available antipsychotic agents, or tend to prescribe just a few with which they are familiar.
This study uses the Herfindahl index to measure the degree to which antipsychotic prescribing is diverse or concentrated within medical centers in the Department of Veterans Affairs.
Patients with schizophrenia who received prescriptions for antipsychotic medications from the Department of Veterans Affairs in fiscal year 2005 were identified. For each facility, the proportion of prescriptions that were written for each antipsychotic medication was computed. The Herfindahl index, which is defined as the sum of the square of the proportionate shares of each medication (i.e., 50% squared = 0.25), was computed for each facility, and its distribution across facilities was examined.
We identified 785,485 prescriptions for antipsychotic medications across 76,787 patients within 128 facilities. With 7 drugs to choose from (first-generation antipsychotics were not differentiated as separate drugs), the Herfindahl could range from 0.14 (if the drugs were prescribed equally) to 1 (if only 1 drug was prescribed to all patients). The Herfindahl averaged 0.20 to 0.21 and ranged from 0.16 to 0.31 across facilities.
The Herfindahl index is a useful metric for describing the degree to which providers use a range of antipsychotic medications in treating patients with schizophrenia and suggests that VA facilities use a diversity of agents, thus taking advantage of the potentially unique drug-patient matches.
The extent to which providers tailor their choice of antipsychotic medication to the particular characteristics of the patient may lead to better quality of care.
The fact that providers do use a range of antipsychotic medications suggests that formulary policies should not reduce access to these drugs.
Further research is needed to construct physician-level measures of prescribing diversity and to examine whether clinical outcomes are improved when providers use a wider range of medications in their practice.
目前尚不清楚医疗服务提供者在多大程度上使用了所有可用的抗精神病药物，还是倾向于只开几种他们熟悉的药物。
本研究使用赫芬达尔指数来衡量退伍军人事务部医疗中心内抗精神病药物处方的多样化程度或集中程度。
确定了2005财年从退伍军人事务部获得抗精神病药物处方的精神分裂症患者。对于每个机构，计算了每种抗精神病药物处方的比例。赫芬达尔指数定义为每种药物比例份额的平方和（即50%的平方 = 0.25），为每个机构计算该指数，并检查其在各机构中的分布情况。
我们在128个机构中为76,787名患者确定了785,485份抗精神病药物处方。有7种药物可供选择（第一代抗精神病药物未作为单独药物区分），赫芬达尔指数范围可以从0.14（如果药物处方均匀）到1（如果所有患者只开1种药物）。赫芬达尔指数平均为0.20至0.21，各机构范围为0.16至0.31。
赫芬达尔指数是描述医疗服务提供者在治疗精神分裂症患者时使用多种抗精神病药物程度的有用指标，表明退伍军人事务部的机构使用多种药物，从而利用了潜在的独特药物 - 患者匹配。
医疗服务提供者根据患者的特定特征调整抗精神病药物选择的程度可能会带来更高的护理质量。
医疗服务提供者确实使用多种抗精神病药物这一事实表明，处方集政策不应减少这些药物的可及性。
需要进一步研究来构建医生层面的处方多样性衡量指标，并检查当医疗服务提供者在实践中使用更广泛的药物时临床结果是否得到改善。
