Mauskopf J, Lacey L, Kempel A, Simpson K
Center for Economics Research, Research Triangle Institute, Research Triangle Park, NC 27709, USA.
Am J Manag Care. 1998 Jul;4(7):1004-12.
In this paper, we present a Markov model for estimating the cost-effectiveness of combination therapy with lamivudine (LMV) and zidovudine (ZDV) compared with ZDV alone. We also compare the predictions of the Markov model for the impact of combination therapy on trial period costs with the actual impact of combination therapy on selected trial period costs estimated from data collected during the clinical trials. In the Markov model, disease stages were defined by CD4 cell count. Based on clinical trial data for patients with CD4 counts higher than 100 cells/mm3, the model assumed that the CD4 cell count level could be maintained above the level at the initiation of therapy for 6.5 months with monotherapy and for 18 months with combination therapy. After this period, transition rates for natural disease progression were used. Incremental lifetime costs and quality-adjusted life years gained with LMV/ZDV compared with ZDV alone were estimated for cohorts of patients initiating antiretroviral therapy at four different CD4 cell count stages. Cost per life year gained varied from $10,000 to $18,000, and cost per quality-adjusted life year gained varied from $14,000 to $27,000. In both cases, the combination therapy was more cost-effective when started earlier in disease progression. These estimates were not sensitive to changes in key parameter values. In addition, the model was used to estimate the impact of combination therapy on healthcare costs during the trial period; these estimated costs were compared with data on the cost of resource use collected during the clinical trial for hospital stays, unscheduled visits, medications, and outpatient procedures. Both the Markov model estimates and the trial data estimates for the trial period showed cost savings in other medical costs, though these were not large enough to completely offset the increased cost for antiretroviral therapy. The model estimates were more conservative than the estimates based on the trial data.
在本文中，我们提出了一个马尔可夫模型，用于评估拉米夫定（LMV）与齐多夫定（ZDV）联合治疗相较于单用ZDV的成本效益。我们还将马尔可夫模型对联合治疗对试验期成本影响的预测，与根据临床试验期间收集的数据估算的联合治疗对选定试验期成本的实际影响进行了比较。在马尔可夫模型中，疾病阶段由CD4细胞计数定义。基于CD4计数高于100个细胞/mm³患者的临床试验数据，该模型假定单药治疗时CD4细胞计数水平可在治疗开始时的水平之上维持6.5个月，联合治疗时可维持18个月。在此期间过后，使用自然疾病进展的转移率。对于在四个不同CD4细胞计数阶段开始抗逆转录病毒治疗的患者队列，估算了与单用ZDV相比，LMV/ZDV联合治疗增加的终身成本和获得的质量调整生命年。每获得一个生命年的成本从10,000美元到18,000美元不等，每获得一个质量调整生命年的成本从14,000美元到27,000美元不等。在这两种情况下，联合治疗在疾病进展早期开始时更具成本效益。这些估算对关键参数值的变化不敏感。此外，该模型用于估算联合治疗对试验期医疗保健成本的影响；将这些估算成本与临床试验期间收集的住院、非计划就诊、药物和门诊手术等资源使用成本数据进行了比较。试验期的马尔可夫模型估算值和试验数据估算值均显示其他医疗成本有所节省，尽管这些节省不足以完全抵消抗逆转录病毒治疗增加的成本。模型估算值比基于试验数据的估算值更为保守。
