- 期刊
以“必須治療數(Number needed to treat)”來解讀治療效應
Using "Number Needed to Treat" to Interpret Treatment Effect
摘要
最近十幾年來，實証醫學（或稱証據醫學）在世界各地風起雲湧，儼然一股顯學，二十一世紀的臨床醫學極可能是實証醫學的年代。隨機含對照組的臨床試驗已被公認為是評估一種新的治療方法療效的黃金標準研究設計。評估治療效應的測量指標可分為二大類：⑴相對效應，包括相對危險性、勝算比、相對危險性降低；⑵絕對效應，包括絕對危險性降低以及必需治療數。若要進行臨床決定分析時，絕對效應指標是比較有意義的指標，因為它們同時考量了研究族群的基線危險性以及治療效果的大小。計算必需治療數很簡單，只要以1除以絕對危險性降低就可得到。但是在解讀NNT(The number needed to treat)時要非常小心，必須要同時考慮幾個因素的影響，包括：是使用哪一種介入性治療（包括藥物及手術）、是使用哪一種對照治療、追蹤觀察時間是多長、研究族群的基線危險性是多少（是否有次族群）、目標事件的發生必須有明確的定義。在說明或引用NNT時，必須要同時報告這幾個因素的狀態，才能有完整的了解和正確的解讀。
並列摘要
Abstract- Evidence-based medicine (EBM) has rapidly emerged as a new paradigm in medicine worldwide. The clinical medicine in twenty-first century could be the era of EBM. Randomized controlled trial has been regarded as the gold standard for evaluating the treatment effect of a new drug or a new therapy. The effect of a treatment versus controls may be expressed in relative or absolute measures. Relative measures include relative risk, relative risk reduction, and odds ratio. Absolute risk reduction and number needed to treat are absolute measures. For rational decision-making, absolute measures are more meaningful because they have taken baseline risk and the amount of clinical benefit into account. The number needed to treat (NNT), the reciprocal of the absolute risk reduction, is a useful estimate of treatment effect. Interpreting a NNT should be very cautious accompanied by information about the experimental treatment (including drugs and surgical procedures), the control treatment for comparison, the baseline risk of the study population, the length of the follow-up period, and an exact definition of the endpoint.