斷層掃描與核子醫學腎上腺掃描於原發性皮質醛酮症之成本效果分析

Abstract

背景：原發性皮質酫酮症為次發性高血壓中最常見的原因，通常是因單側腎上腺腺瘤或是雙側腎上腺增生引起，前者手術治療可治癒，後者則以內科治療為主。斷層掃描、腎上腺靜脈血取樣與核子醫學腎上腺掃描常被用來評估原發性皮質酫酮症之病因以及患側診斷，腹部斷層掃描可評估腎上腺病灶之解剖學特徵，但其敏感度差異很大；腎上腺靜脈血取樣為現今之診斷標準，但為侵入性檢查，且具高度技術需求；核子醫學腎上腺掃描早期受限於影像解析度不足，效果不彰，隨著單光子放射斷層攝影術與斷層掃描融合技術的發展，準確度大幅提升。以上檢查之準確度及適用時機未有定論，但至今未有研究對其成本及效果進行分析。 目的：本研究探討腹部斷層掃描（CT）、核子醫學腎上腺掃描平面造影（NP-59 planar）、輔以單光子放射斷層攝影術（NP-59 SPECT）以及輔以單光子放射斷層攝影術併斷層掃描融合技術（NP-59 SPECT/CT）四種影像學檢查，在診斷原發性皮質酫酮症病因上之準確性、平均醫療成本以及成本效果分析。 方法：本研究回溯式搜尋TAIPAI資料庫，共27位原發性皮質酫酮症病患納入研究，皆有接受腹部斷層掃描與核子醫學腎上腺掃描，並以最終病理結果為診斷標準。研究中分析四項檢查之準確度，並以決策樹模型之方式，計算機率與平均成本，設定檢查準確度與檢查效用度為效果指標，探討成本效果分析，最後以敏感度分析方式探討變項變化對平均成本之影響。 結果：四種檢查中，NP-59 SPECT/CT準確度最高，與CT及NP-59 planar相比，呈現邊緣性的統計意義。平均成本亦以NP-59 SPECT/CT最低，NP-59 planar為平均成本最高之檢查。以檢查準確度為效果指標時，NP-59 SPECT/CT之成本效果比值最低；以檢查應用度為效果指標時，NP-59 SPECT/CT之成本效果比值亦為最低，NP-59 planar則為無效之檢查。敏感度分析中以NP-59 SPECT/CT之敏感度為變相變化時，即使其敏感度降至0%，平均成本亦低於CT；以NP-59 SPECT/CT之特異度為變相變化時，當其特異度降至59.5%以下時，NP-59 SPECT/CT之平均成本開始高於CT之平均成本。 結論：本研究顯示NP-59 SPECT/CT在診斷原發性皮質酫酮症之病因上述四種影像學檢查中最為準確，平均成本最低，成本效果比值最低之檢查。NP-59 SPECT/CT在敏感度與特異度的變動上保有對於CT之成本效果比值優勢。依此結論可提供臨床醫師在處理原發性皮質酫酮症時另一種參考方向，採用更有效果之處置。

Background：Primary aldosteronism is the most common cause of secondary hypertension. The two main causes of primary aldosteronism are aldosterone-producing adenoma, which could be cured by surgical intervention, and bilateral adrenal hyperplasia, which should be medical-treated. Computed tomography, adrenal venous sampling and adrenal scintigraphy are usually used for the etiology and lateralization of primary aldosteronism. Computed tomography is based on the anatomical findings, but it has wide variation of sensitivity. Adenal venous sampling is the gold standard for latearalization, but it is invasive and highly technical-dependent. Adrenal scintigraphy has limited role in primary aldosteronism during early days due to resolution. With the SPECT and SPECT/CT fusion imaging techique, the accuracy of adrenal scintigraphy is significant improved. The clinical algorithm for these modalities has not been well-established, and there are no studies concerning about the cost-effectiveness. Objective：This study aimed on the comparison of the accuracy, average cost and cost-effectiveness analysis of four imaging modalities for differentiating the etiology of primary aldosteronism, including CT, NP-59 planar, NP-59 SPECT and NP-59 SPECT/CT. Methods：We retrospectively included 27 clinical-confirmed primary aldosteronism patients from TAIPAI database. All of them had CT, NP-59 adrenal scintigraphy (plaran, SPECT and SPECT/CT) studies and pathology reports of adrenal lesion. The accuracy and average cost of these four imaging modalities were analyzed. By decision tress and setting effectiveness as diagnostic accuracy and diagnostic utility, cost-effectiveness were also analyzed. Sensitivity analysis were performed to determine the impact on the average cost while the variables changed. Results：NP-59 SPECT/CT is the most accurate study among four imaging modalities, with borderline significance as compared with NP-59 planar and CT. NP-59 SPECT/CT bares the lowest average cost, and NP-59 planar bares the highest average cost. By setting diagnostic accuracy as the effectiveness, NP-59 SPECT/CT has the lowest cost-effectiveness ratio. If setting diagnostic utility as the effectiveness, NP-59 planar is considered a ineffectiveness study. In sensitivity analysis, if the sensitivity of NP-59 SPECT/CT decreases to 0%, the average cost of NP-59 SPECT/CT is still lower the average cost of CT. The average cost of NP-59 SPECT/CT is higher than the average cost of CT while the specificity of NP-59 SPECT/CT decreases to 59.5%. Conclusion：Our study suggests that NP-59 SPECT/CT is the most accurate, the lowest average cost and the most cost-effective study among these four imaging modalities in differentiating the etiology of primary aldosteronism. It shows no significant impact on cost-effectiveness ratio as compared with CT while the sensitivity and specificity of NP-59 SPECT/CT changes. Aside from clinical concern, this result provides physicians consider the decision in another way to provide more effective management in primary aldosteronism.