Introduction: In asthma patients, reductions in FEV3 and FEV6 may reflect early bronchial obstruction and disease severity. This study aimed to evaluate FEV3 and FEV6 as complementary spirometric parameters to FEV1 for assessing asthma severity and control. Material and methods: Multicenter prospective cross-sectional study exhaustively including 221 adult asthma patients recruited from pulmonology departments at Oran University Hospital (EHU) and Bechar Hospital (EPH) from 04/01/2020 to 12/31/2023. Patients were classified according to GINA guidelines for asthma severity (intermittent, mild, moderate, severe) and control status (controlled, partially controlled, uncontrolled). Spirometric measurements (FEV1, FEV3, FEV6, FVC) were obtained using standardized procedures and expressed as percentages of predicted values. Statistical analyses included chi-square tests for categorical variables, Student t-tests and one-way ANOVA for continuous variables, and Pearson/Spearman correlations. Significance was set at p<0.05 using SPSS software. Results: A population of 221 asthma patients was collected. Mean age was 48.9±15.3 years with female predominance (sex ratio 0.27). Asthma was divided according to its severity into intermittent asthma in 2.7% of cases, mild in 46.2% of cases, moderate in 47.5% of cases, and severe in 3.6% of cases. Total control is present in 29.9% of cases while it is impaired (partially controlled and uncontrolled) in 70.1% of cases.FEV1<80% predicted in 50.5% of cases (women 52.9% vs men 42.6%) and 60 years). Negative correlations between age and FEV1 (r=-0.173, p=0.01), FEV3, and FEV6. Mean FEV1/FEV3/FEV6 values decreased significantly with increasing asthma severity (ANOVA p<0.001) and worsening control (p<0.001). Higher FEV3/FEV6 values observed in physically active patients (p=0.03). Conclusion: FEV3 and FEV6 accurately reflect asthma severity and control, predicting FEV1 without replacing it as the reference parameter. Their systematic integration into spirometric protocols would optimize monitoring, particularly in patients with limited cooperation.
