Boodhna Trishal, Crabb David P
Division of Optometry and Visual Science, School of Health Sciences, City, University of London, Northampton Square, London,, EC1V 0HB, UK.
BMC Health Serv Res. 2016 Oct 22;16(1):611. doi: 10.1186/s12913-016-1849-9.
Chronic open angle glaucoma (COAG) is an age-related eye disease causing irreversible loss of visual field (VF). Health service delivery for COAG is challenging given the large number of diagnosed patients requiring lifelong periodic monitoring by hospital eye services. Yet frequent examination better determines disease worsening and speed of VF loss under treatment. We examine the cost-effectiveness of increasing frequency of VF examinations during follow-up using a health economic model.
Two different VF monitoring schemes defined as current practice (annual VF testing) and proposed practice (three VF tests per year in the first 2 years after diagnosis) were examined. A purpose written health economic Markov model is used to test the hypothesis that cost effectiveness improves by implementing proposed practice on groups of patients stratified by age and severity of COAG. Further, a new component of the model, estimating costs of visual impairment, was added. Results were derived from a simulated cohort of 10000 patients with quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) used as main outcome measures.
An ICER of £21,392 per QALY was derived for proposed practice improving to a value of £11,382 once savings for prevented visual impairment was added to the model. Proposed practice was more cost-effective in younger patients. Proposed practice for patients with advanced disease at diagnosis generated ICERs > £60,000 per QALY; these cases would likely be on the most intensive treatment pathway making clinical information on speed of VF loss redundant. Sensitivity analysis indicated results to be robust in relation to hypothetical willingness to pay threshold identified by national guidelines, although greatest uncertainty was allied to estimates of implementation and visual impairment costs.
Increasing VF monitoring at the earliest stages of follow-up for COAG appears to be cost-effective depending on reasonable assumptions about implementation costs. Our health economic model highlights benefits of stratifying patients to more or less monitoring based on age and stage of disease at diagnosis; a prospective study is needed to prove these findings. Further, this works highlights gaps in knowledge about long term costs of visual impairment.
慢性开角型青光眼（COAG）是一种与年龄相关的眼病，会导致不可逆转的视野（VF）丧失。鉴于大量确诊患者需要医院眼科服务进行终身定期监测，为COAG提供医疗服务具有挑战性。然而，频繁检查能更好地确定疾病恶化情况以及治疗期间VF丧失的速度。我们使用健康经济模型来研究在随访期间增加VF检查频率的成本效益。
研究了两种不同的VF监测方案，分别定义为当前做法（每年进行VF检测）和建议做法（诊断后的前2年每年进行3次VF检测）。使用一个专门编写的健康经济马尔可夫模型来检验以下假设：通过对按COAG年龄和严重程度分层的患者群体实施建议做法，成本效益会提高。此外，模型中增加了一个估计视力损害成本的新组件。结果来自一个模拟的10000名患者队列，以质量调整生命年（QALYs）和增量成本效益比（ICERs）作为主要结局指标。
建议做法得出的ICER为每QALY 21392英镑，一旦将预防视力损害的节省费用纳入模型，该值可提高到11382英镑。建议做法在年轻患者中更具成本效益。诊断时患有晚期疾病的患者采用建议做法产生的ICER超过每QALY 60000英镑；这些病例可能处于最强化的治疗路径，使得关于VF丧失速度的临床信息变得多余。敏感性分析表明，尽管最大的不确定性与实施成本和视力损害成本的估计相关，但结果相对于国家指南确定的假设支付意愿阈值而言是稳健的。
根据对实施成本的合理假设，在COAG随访的最早阶段增加VF监测似乎具有成本效益。我们的健康经济模型强调了根据诊断时的年龄和疾病阶段对患者进行或多或少监测分层的益处；需要进行前瞻性研究来证实这些发现。此外，这项工作突出了在视力损害长期成本知识方面的差距。
