Frailty as a Predictor of Outcomes in Optiflow

High-flow nasal cannula (HFNC) oxygen therapy has been increasingly used in acute settings for patients with hypoxic respiratory failure. More evidence is needed to identify which patients are more likely to benefit from HFNC over conventional oxygen therapy. There is limited published evidence regarding the impact of frailty on outcomes in patients treated with HFNC. Does a higher Clinical Frailty Score confer a worse outcome in those treated with HFNC? A retrospective cohort study of 96 patients who received HFNC was conducted at Kingston Hospital. Patients were divided into three groups based on their Clinical Frailty Score (CFS): CFS 1-4 (n=32), CFS 5-6 (n=44), and CFS 7-8 (n=20). Chi-squared test of independence was performed for significance in categorical variables, and for continuous variables, non-parametric testing using the Kruskal-Wallis H test was performed. The 30-day mortality in the CFS 7-8 group was found to be higher (55%) as opposed to the CFS 1-4 group (41%) and CFS 5-6 (55%) (p=0.48). Frail patients with a pneumonic process had a higher 30-day mortality rate than non-frail patients (8 of 12 or 75% of patients with CFS 7-8 p=0.034) and when compared to frail patients with non-pneumonic processes (2 of 7 or 29% of patients with CFS 7-8 p=0.18). Mortality in the hospital whilst receiving HFNC was higher in the frailer groups (CFS 5-6: 18 of 44 (41%); CFS 7-8: 6 of 20 (30%)) compared to the less frail group (CFS 1-4: 6 of 32 (19%)) (p=0.360). Our results suggest that frail patients experienced a higher mortality rate and lower weaning rate, particularly if the indication for HFNC was an underlying pneumonic process, suggesting that while HFNC provides benefits, its efficacy may be limited. Further evidence is needed to assess the efficacy of HFNC in frailty.