NNT和NNH的概念及应用

Something Needed to Pay Attention in the Use of NNT and NNH

阐述了NNT和NNH的定义和用途。NNT用于治疗前评估不治疗给患者造成损害的可能性,NNH用于评估治疗可能给患者造成伤害的可能性,也可用于比较干预措施与阳性药物比较的相对获益或受损。与安慰剂比较时,NNT或NNH为绝对效应量;与阳性药物比较时,NNT或NNH为相对效应量。当描述相对效应量时,通过RR或OR、RD表示干预措施与对照的效应量大小关系。

NNT defines the number of patients who need to be treated in order to achieve one additional favorable outcome,and NNH is defined as the number of patients who must be treated with a therapy in order to have one additional patient suffer an adverse effect compared with the control treatment. This is the most important thing that should be considered before administering a treatment. NNT can also be used to assess the relative benefit or harm in the comparison of intervention versus positive control. If the effect is smaller in the intervention group than that in the control group,NNT should be used; if the effect is bigger in the intervention group than that in the control group,NNH should be used. When comparison is made between an intervention versus placebo,NNT and NNH are absolute outcomes; when an intervention is compared to a positive control,NNT and NNH are relative outcomes. RR or OR or RD may help to judge which comparator has bigger or smaller effect,and whether NNT or NNH should be used.