Vickers A
Integrative Medicine Service, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Complement Ther Med. 2001 Dec;9(4):234-6. doi: 10.1054/ctim.2001.0467.
Complementary therapies are often used to treat patients with persisting conditions. In a typical randomized trial, patients are assessed for symptom severity at baseline, randomized to treatment or control and then reassessed after a suitable follow-up period. It can be shown that the number of patients required for such trials can be reduced by the use of two methods: repeat measurement and analysis of co-variance (ANCOVA). An example is given of a trial of acupuncture for back pain. Administering the pain questionnaire twice at baseline and four times at follow-up reduces the number of patients by approximately 20% compared to single questionnaire administration. Use of ANCOVA decreases the number of patients by approximately a further 10%. There are considerable economic and ethical advantages to reducing sample size by a third; however, ANCOVA is statistically complex and expert statistical help is required.
辅助疗法常用于治疗患有持续性疾病的患者。在典型的随机试验中，患者在基线时接受症状严重程度评估，随机分配至治疗组或对照组，然后在适当的随访期后重新评估。可以证明，通过使用两种方法可以减少此类试验所需的患者数量：重复测量和协方差分析（ANCOVA）。给出了一个针灸治疗背痛试验的例子。与单次问卷调查相比，在基线时进行两次疼痛问卷调查，在随访时进行四次，可将患者数量减少约20%。使用ANCOVA可使患者数量再减少约10%。将样本量减少三分之一具有相当大的经济和伦理优势；然而，ANCOVA在统计学上较为复杂，需要专业的统计帮助。
