Suvorexant for Insomnia: Efficacy and Safety Profile
Data Extraction
Principal findings are summarised, including time to sleep onset and assessment of sleep maintenance as measured by patient estimate and by polysomnography. Number needed to treat (NNT), and number needed to harm (NNH), comparing suvorexant with placebo, are calculated where appropriate. The methodology of this technique is described in detail elsewhere. NNT and NNH are measures of effect size and indicate how many patients would need to be treated with one agent instead of the comparator to encounter one additional outcome of interest. Lower NNTs are evidenced when there are large differences between the interventions in question. For example, a NNT of two would be a very large effect size, as a difference is encountered after treating just two patients with one of the interventions vs. the other. A NNT of 50 would mean little difference between the two interventions, as it would take treating 50 patients to encounter a difference in outcome. NNH is used when referring to undesirable events. A useful medication is one with a low NNT and a high NNH when comparing it with another intervention; a low NNT and a high NNH would mean one is more likely to encounter a benefit than a harm. A rule of thumb is that single digit NNTs for efficacy measures suggests that the intervention has potentially useful advantages, and that double digit or higher NNHs for adverse outcomes indicate that the intervention is potentially tolerable. Where possible and applicable, for each NNT or NNH, 95% confidence intervals (CI) are computed. For where the NNT or NNH is not statistically significant at the p < 0.05 threshold, the notation 'ns' is shown.