IGHE and Airway obstruction: Furthermore, follow-up analyses of the TALC study data found that adult asthma patients with higher cholinergic tone (as indicated by a lower resting heart rate) and the extent of airway obstruction (as indicated by the FEV1/FVC ratio) predicted a positive clinical response to tiotropium (versus salmeterol); ethnicity, gender, atopy, IgE levels, asthma duration, and BMI were not predictors [65].