Clinically important estimates of improvement after septoplasty

OBJECTIVE: A statistically significant improvement in nasal obstruction ratings following septoplasty is not necessarily clinically important. This study aimed to establish useful measures of septoplasty success, namely the minimal clinically important difference and the desirable clinically important difference. METHODS: Patients rated nasal obstruction on a 0–100 visual analogue scale pre-operatively and at 5.5 months post-operatively. Global outcome rating (completely, much, or somewhat improved, unchanged or worse) served as the anchor post-operatively. Minimal clinically important difference is the visual analogue scale value between ‘somewhat improved’ and ‘unchanged’, and the desirable clinically important difference is that between ‘much’ and ‘somewhat improved’. RESULTS: Statistically significant improvement in visual analogue scale scores was not clinically important. The minimal clinically important difference (daytime value of 9.5) represented 15.1 per cent improvement and the desirable clinically important difference (daytime value of 28.5) represented 45.2 per cent, without gender or age differences. CONCLUSION: Clinical success can be defined using a minimal clinically important difference of 15 per cent improvement over a patient's baseline value. Other studies’ ratings of ‘satisfactory’ outcome coincided with a desirable clinically important difference of 45 per cent over baseline. These values are suggested as relevant indicators of septoplasty success.