The Practical Role of FEF_25-75 in Young Patients with Allergic Rhinitis

Allergic rhinitis (AR) is a relevant risk factor asthma as it may frequently precede asthma onset. There is evidence that lung function may be early impaired in AR patients. In this regard, the forced expiratory flow at 25%-75% of vital capacity (FEF_25-75) could be a reliable marker of bronchial impairment in AR. Therefore, the present study investigated the practical role of FEF_25-75 in young people with AR. The parameters included history, body mass index (BMI), lung function, bronchial hyperresponsiveness (BHR), and fractional exhaled nitric oxide (FeNO). This cross-sectional study included 759 patients (74 females and 685 males, mean age of 29.2 years) suffering from AR. The study demonstrated a significant association between low FEF_25-75 values and BMI (OR 0.80), FEV₁ (OR 1.29), FEV₁/FVC (OR 1.71), and BHR (OR 0.11). Stratifying the patients on the basis of the presence (or absence) of BHR, sensitization to house dust mites (OR 1.81), AR duration (OR 1.08), FEF_25-75 (OR 0.94), and FeNO (OR 1.08) were associated with BHR. Stratifying patients based on high FeNO values (>50 ppb), BHR was associated with high FeNO (OR 39). In conclusion, the present study showed that FEF_25-75 was associated with low FEV₁ and FEV₁/FVC and BHR in AR patients. Therefore, spirometry should be considered in the long-term workup of patients with allergic rhinitis as impaired FEF_25-75 might suggest an initial progression toward asthma.