背景:抗精神病药相对于安慰剂的优越性存在争议。一个原因是通常在荟萃分析中使用的效应大小指数是以标准偏差为单位。许多其他指数,其中一些更直观,存在。
方法:我们解释公式,优势,以及13种效应大小指数的局限性:平均差(MD),标准化均值差(SMD),相关系数,平均比率(RoM,端点和更改数据),改进分数(IF),药物反应分数(DRF),最小临床重要差异单位(MCIDU),从SMD(NNT)导出的需要治疗的数量,赔率比(OR),相对风险(RR),和SMD衍生的风险差异(RD),药物反应和安慰剂反应百分比。我们将这些指标应用于比较抗精神病药物与安慰剂治疗急性精神分裂症的荟萃分析。
结果:所有抗精神病药物与安慰剂(105项试验,22741名参与者)的差异为:MD9.4(95%CI8.4,10.2)PANSS点,SMD0.47(0.42,0.51),相关系数0.23(0.21,0.25),RoM终点0.83(0.81,0.85),RoM变更1.94(1.84,2.02),IF(%)49(46,51),DRF(%)94(84,102),MCIDU0.63(0.56,0.68),NNT5(5,6),或2.34(2.14,2.52),RR1.67(1.59,1.73),RD20%(18-22),与安慰剂的30%相比,药物的50%(48,52)有所改善。提供了与安慰剂相比的单个药物的结果,也是。
结论:将这些指数加在一起显示出实质性的,但与安慰剂相比,抗精神病药并没有很大的优势。必须考虑试验中患者的一般慢性性。未来的荟萃分析除了标准化均值差异外,还应报告其他效应大小指数,特别是药物和安慰剂组的应答者百分比。它们可以很容易地得出,并且可以增强对研究结果的解释。
BACKGROUND: The magnitude of the superiority of antipsychotics over placebo is debated. One reason is that the effect-size index which is usually used in meta-analyses is in standard deviation units. Many other indices, some of which are more intuitive, exist.
METHODS: We explain the formulae, advantages, and limitations of 13 effect-size indices: Mean Difference (MD), Standardized-Mean-Difference (SMD), Correlation Coefficient, Ratio-of-Means (RoM, endpoint and change data), Improvement Fraction (IF), Drug-Response Fraction (DRF), Minimally-Clinically-Important-Difference-Units (MCIDU), Number-Needed-to-Treat-derived from SMD (NNT), Odds Ratio (OR), Relative Risk (RR), and Risk Difference (RD) derived from SMD, Drug-response and Placebo-response in percent. We applied these indices to meta-analyses comparing antipsychotic drugs with placebo for acute schizophrenia.
RESULTS: The difference of all antipsychotics pooled vs placebo (105 trials with 22741 participants) was: MD 9.4 (95% CI 8.4,10.2) PANSS points, SMD 0.47 (0.42,0.51), Correlation coefficient 0.23 (0.21,0.25), RoM endpoint 0.83 (0.81,0.85), RoM change 1.94 (1.84,2.02), IF (%) 49 (46,51), DRF (%) 94 (84,102), MCIDU 0.63 (0.56,0.68), NNT 5 (5,6), OR 2.34 (2.14, 2.52), RR 1.67 (1.59,1.73), RD 20% (18-22), and 50% (48, 52) improved on drug compared to 30% on placebo. Results of individual drugs compared to placebo are presented, as well.
CONCLUSIONS: Taken together these indices show a substantial, but not a large superiority of antipsychotics compared to placebo. The general chronicity of the patients in the trials must be considered. Future meta-analyses should report other effect size indices in addition to the Standardized-Mean-Difference, in particular percentage responders in the drug and placebo groups. They can be easily derived and would enhance the interpretation of research findings.