Correlation of GINA asthma control with lung volumes, airway resistance, diffusion and 6MWT

Abstract

Introduction - Current GINA guidelines recommend control based management. Subjective assessment of symptom control may lack in estimating disease severity and functional ability. Aims - To correlate Asthma control with lung volumes, airway resistance, conductance ,diffusion capacity (DLCO) and 6 minute walk test (6MWT). Methods - 64(18 females & 46 males) Asthmatic patients, stratified according to GINA asthma control, underwent spirometry, body plethysmography, DLCO and 6MWT. Comparison was done using ANOVA and Chi Square tests. Results - Indices of hyperinflation ie. FRC%,RV%,RV/TLC% (not TLC%) as well as airway resistance(Raw) were significantly increased while FEV1%, specific airway conductance(sGaw) along with 6 minute walk distance(6MWD) were significantly decreased with worsening of Asthma control. Uncontrolled Asthmatics had longer duration of illness (p=0.029) and greater BMI (p=0.04) as compared to controlled one9s. Conclusion - Lung volumes ,airway resistance & conductance along with 6MWT may supplement GINA level of Asthma control in assessing patient9s underlying physiological as well functional status over time.