Rosen Sydney, Long Lawrence, Fox Matthew, Sanne Ian
Center for International Health and Development, Boston, MA 02118, USA.
J Acquir Immune Defic Syndr. 2008 Jul 1;48(3):334-44. doi: 10.1097/QAI.0b013e31817ae5ef.
Most first-line antiretroviral therapy regimens in Africa include stavudine (d4T), despite the high incidence of toxicities related to it. We estimated the cost and cost-effectiveness of switching from d4T to tenofovir disoproxil fumarate (TDF) in South Africa.
A model was developed to estimate the proportion of patients in a hypothetical cohort who experienced d4T- and TDF-related events over the 2 years after antiretroviral therapy initiation. Transition probabilities, event and drug costs, and utility losses were estimated from primary data and the literature. Outcomes included incremental cost, incremental cost-effectiveness ratio per quality-adjusted life year gained, and threshold prices for TDF.
After 2 years, 82.5% of the d4T scenario cohort remained on d4T, 16.6% had switched to AZT, 0.8% had died, and 414 events that did not lead to a drug change had occurred. In the TDF scenario, 97.5% of the cohort remained on TDF. At a baseline cost of TDF of $17.00/month, the incremental cost of the TDF scenario was $128/patient/year and the incremental cost-effectiveness ratio was $9007 per quality-adjusted life year gained. The change to TDF would be cost neutral for the government at a price of $6.17/month and highly cost effective at a price of $12.94/month.
At a TDF price of $17.00/month, savings on d4T toxicity management will offset roughly 20% of the higher price of TDF. The price of TDF would have to fall substantially to make the change cost neutral for South Africa in budgetary terms, but it would be highly cost effective at a price only slightly less than what is currently available.
尽管司他夫定（d4T）存在较高的相关毒性发生率，但非洲大多数一线抗逆转录病毒治疗方案仍包含该药物。我们估算了南非从d4T转换为替诺福韦酯（TDF）的成本及成本效益。
建立一个模型，以估算在抗逆转录病毒治疗开始后的2年中，假设队列中经历与d4T和TDF相关事件的患者比例。从原始数据和文献中估算转移概率、事件及药物成本以及效用损失。结果包括增量成本、每获得一个质量调整生命年的增量成本效益比，以及TDF的阈值价格。
2年后，d4T方案队列中82.5%的患者仍使用d4T，16.6%已转换为齐多夫定（AZT），0.8%死亡，且发生了414起未导致药物更换的事件。在TDF方案中，97.5%的队列仍使用TDF。在TDF基线成本为每月17.00美元的情况下，TDF方案的增量成本为每人每年128美元，增量成本效益比为每获得一个质量调整生命年9007美元。对于政府而言，当价格为每月6.17美元时，转换为TDF将实现成本中性，当价格为每月12.94美元时则具有很高的成本效益。
在TDF价格为每月17.00美元时，d4T毒性管理方面的节省将大致抵消TDF较高价格的20%。TDF的价格必须大幅下降才能使南非在预算方面实现成本中性转换，但在仅略低于当前可用价格的情况下，它将具有很高的成本效益。
