幽門螺旋桿菌糞便抗原檢查與碳十三尿素呼氣試驗對於預防胃癌之成本效果分析

Abstract

研究背景 胃癌於全世界的發生率排行所有癌症的第五位，死亡率則是所有癌症的第三位，儘管胃癌的發生率在大部分的人群中呈現下降的趨勢，它仍然是全球重要的癌症。相較於北美和北歐，東亞的胃癌發生率顯著較高。胃癌的初段預防策略是近期興起的胃癌預防策略，主要是透過根除幽門螺旋桿菌來進行。在第一階段進行幽門螺旋桿菌感染的篩檢，而陽性患者在第二階段進行幽門螺旋桿菌的根除。在幽門螺旋桿菌感染篩檢方面，近期有研究指出幽門螺旋桿菌糞便抗原檢查相較於碳13尿素呼氣試驗有更低的成本，且有不錯的敏感度以及特異度，或許能應用在大規模的社區篩檢中，然而幽門螺旋桿菌糞便抗原檢查是否相對於碳13尿素呼氣試驗具有較好的成本效果，仍有待驗證。 研究目的 本研究的目的如下： (1) 分析幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗篩檢策略相較於不進行任何介入對於預防胃癌的成本效果； (2) 分析幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗對於預防胃癌的相對成本效果； (3) 探討在不同支付意願 (willingness to pay, WTP)的情況下，幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗符合成本效益的可能性。 研究方法 以文獻回顧的方式取得流行病學與相關成本的參數估計值，包括：幽門螺旋桿菌盛行率、胃癌的年齡別發生率和致死率、根除幽門螺旋桿菌的根除率和效益以及治療胃癌和幽門螺旋感染之成本等，用以建立三個馬可夫模型以模擬對於馬祖地區的居民採取不進行任何介入、幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗等三種不同策略後對於預防胃癌的成本效果，進而比較三項策略之間的優劣。主要的結果為每獲得一生命年所需的花費，折現率為每年3%。 研究結果 在基礎值分析中，幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗之策略相較於不進行任何介入對於預防胃癌皆能以更低的成本獲得更多的生命年，具有絕對的優勢。碳13尿素呼氣試驗相較於幽門螺旋桿菌糞便抗原檢查的增量成本效果比 (incremental cost-effectiveness ratio, ICER) 為每一生命年10,367美元，低於支付意願的每一生命年25,792美元，故符合成本效果。幽門螺旋桿菌糞便抗原檢查的敏感度是否大於95%會對尿素呼氣試驗相較於糞便抗原檢查的增量成本效果比有決定性的影響。當支付意願為每一生命年25,792美元，尿素呼氣試驗和糞便抗原檢查符合成本效益的機率分別為83%和17%。支付意願閾值為每一生命年9,500美元，當支付意願大於每一生命年9,500美元時，碳13尿素呼氣試驗是最可能符合成本效益的策略，然而，當支付意願小於每一生命年9,500美元時，幽門螺旋桿菌糞便抗原檢查是最可能符合成本效益的策略。 研究結論 相較於不進行任何介入，幽門螺旋桿菌糞便抗原檢查與碳13尿素呼氣試驗對於預防胃癌皆是符合成本效果的方式。碳13尿素呼氣試驗相較於幽門螺旋桿菌糞便抗原檢查亦符合成本效果，但這該結果會受到糞便抗原檢查的敏感度影響。當支付意願較高時，碳13尿素呼氣試驗有更高的可能性符合成本效益，而當支付意願較低時，幽門螺旋桿菌糞便抗原檢查則更有可能符合成本效益。

Background: Gastric cancer is the 5th most common neoplasm and the 3rd most deadly cancer in the world. Despite the decreasing trend in gastric cancer in most people, the disease remains one of the most common cancers. Incidence of gastric cancer are markedly higher in Eastern Asia, whereas the rates in Northern America and Northern Europe are generally low. The eradication of Helicobacter pylori (H. pylori) infection has been recently suggested as a main primary prevention strategy for gastric cancer. Screening for H. pylori infection is performed in the first stage and positive patients undergo H. pylori eradication in the second stage. In terms of H. pylori infection screening, a recent study has pointed out that the cost of H. pylori stool antigen test (SAT) was lower than 13C urea breath test (UBT) and the sensitivity and specificity of SAT were great. SAT screening was feasible and advisable for wide application in the community. However, the relative cost-effectiveness between SAT and UBT was unknown. Aims: Our thesis was (1) to analyze that SAT or UBT is more cost-effective or not than no intervention. (2) to analyze the relative cost-effectiveness between SAT and UBT. (3) to evaluate the possibility that SAT or UBT is the most cost-effective strategy in different willingness to pay (WTP). Materials and Methods: Obtained parameters of epidemiology and relevant costs through literature review, including prevalence of H. pylori infection, incidence and fatality rate of gastric cancer, H. pylori eradication rate, and relevant costs of screenings and treatments. Three Markov models were established to simulate the processes of three strategies (no intervention, SAT screening and UBT screening) adopted to prevent gastric cancer for residents in the Matsu. Cost-effectiveness was compared between three strategies. The main outcome measure was cost per life-year gained with a 3% annual discount rate. Results: In base-case estimates, adopting SAT screening or UBT screening strategy could gain more life-year with less cost than no intervention so two primary prevention strategies dominated no intervention. The incremental cost-effectiveness ratio (ICER) for UBT screening versus SAT screening was U.S. $10,367 per life-year gained. It is lower than U.S. $25,792 per life-year gained (WTP), so UBT screening was cost-effective compared with SAT screening. This result was sensitive to the sensitivity of SAT screening ≧95%.When WTP was U.S. $25,792 per life-year gained, the possibility that UBT screening and SAT screening were the most cost-effective strategies was 83% and 17% respectively. The threshold of WTP was U.S. $9,500 per life-year gained. When WTP was more than U.S. $9,500 per life-year gained, UBT screening was the most likely cost-effective strategy. However, when WTP was less than U.S. $9,500 per life-year gained, SAT screening was the most likely cost-effective strategy. Conclusion: SAT screening or UBT screening is cost-effective strategy for gastric cancer prevention compared with no intervention. UBT screening is cost-effective compared with SAT screening, but the relative cost-effectiveness was sensitive to the sensitivity of SAT screening. When WTP is higher, UBT screening is more likely the most cost-effective strategy. However, when WTP is lower, SAT screening is more likely the most cost-effective strategy.