Statistical Fragility of Saline Nasal Irrigation for Rhinosinusitis Is Incomplete Without Robustness Assessment

Abstract

A recent systematic review of randomized controlled trials evaluating saline nasal irrigation (SNI) for rhinosinusitis correctly identifies moderate-to-high statistical fragility across eight trials but cannot determine whether non-significant results represent genuine nil effects or underpowered detections of real treatment benefits. Statistical classification of significance using p-values is the primary metric analyzed. The stability of this classification, as measured by the fragility index, is a derived, secondary metric of statistical significance. While the systematic review addressed both of these metrics, it failed to take into account robustness — the distance from therapeutic neutrality, accounting for variability. Robustness provides the missing complement needed to distinguish near-null effects from fragile-but-real detections. Reporting the statistical evidence triplet of significance, fragility, and robustness in future SNI reviews would materially improve the interpretation of evidence for clinical decision-making in rhinosinusitis.