近年台灣地區民眾的平均壽命因醫療進步及環境改善等因素而大幅延長，主要死因轉變為中老年疾病或是慢性病，需要長期追蹤、治療，衍生的醫療費用也將隨人口老化而逐步上升，未來極有可能對我國全民健康保險的財務自主產生重大影響。本文主旨在於探討人口老化對重大傷病的影響，包括重大傷病患病人數及醫療費用的推估，並討論推估結果代表的意義。本文資料分析以全民健康保險重大傷病資料庫 (1996 年至2001 年) 為依據，使用精算原則估計重大傷病門診醫療金額 (例如：每人平均就診次數、平均每次就診金額、罹患重大傷病機率) ，再配合內政部的人口資料與人口變動要素合成 (cohort component) 方法，推估未來重大傷病門診醫療費用。研究發現重大傷病的門診醫療費用將隨時間直線上升，與我國人口老化的趨勢頗為一致，醫療費用的上升必對我國全民健康保險的財務造成重大影響；另外，本文亦計算個人在一定期間之重大傷病收支平衡年繳保費，此部份除了可以應用在實支實付型的商業保險外，也可以應用於評估健保政策為一定期間不調整保費時，為維持其財務收支平衡之應收總保費。

Recently, according to information from Taiwan’s National Health Insurance database, the medical expenditure on critical illness and injury has increased significantly because of an aging population. In this paper we are interested in investigating the impact of the aging population on the cost of critical illness and injury. In the first part of this research, we make use of Taiwan’s National Health Insurance database from 1996 to 2001 to estimate the number of people suffering critical illness and injury. In particular, we apply actuarial methods and the method of cohort component to estimate outpatient medical expenditure of the critical illness and injury. The estimation shows that the projection of medical expenditure due to critical illness and injury grows linearly with time. This effect is consistent with the trend of an increase of numbers in elderly. It implies that an aging population will lead to a significant financial impact on Taiwan’s national health insurance program. Furthermore, in the second part of this research, we construct a Markov model to calculate the expected premiums of critical illness and injury insurance under both social and commercial insurance systems. We then evaluate the required cost of critical illness and injuries in order to keep a financial balance for the Taiwan National Health Insurance program.