9.

Trial Sequential Analysis of comparison: 8 Alpidem versus placebo, outcome: 8.3 Anxiety, Hamilton Anxiety Rating Scale (HAM‐A). Trial Sequential Analysis on anxiety evaluated with HAM‐A assessing a minimal relevant clinical difference (MIREDIF) of 5 points, and a variance of 103 points (empirical data), was performed based on a type I error of 1.25%, a type II error of 10% (90% power), and diversity of 0%. The diversity‐adjusted required information size (DARIS) was 235 participants, and the Trial Sequential Analysis‐adjusted confidence interval is ‐6.28 to 3.08. The blue line represents the cumulative Z‐score of the meta‐analysis. The green lines represent the conventional statistical boundaries of P = 0.05. The red inward‐sloping lines represent the trial sequential alpha‐spending monitoring boundaries, while the red outward‐sloping lines represent the beta‐spending (futility) boundaries. The cumulative Z‐curve crosses the beta‐spending (futility) boundaries, showing that an intervention effect, if any, is less than 5 points.