LAUSR

Biomarkers in chronic obstructive pulmonary disease may be clinical (prior exacerbation history), physiological (forced expiratory volume in one second), or blood based (eosinophil count or fibrinogen level). There has been recent interest in using biomarkers to predict response to therapy in clinical practice. The benefits of inhaled therapy depend on correct use of the inhaler including an appropriate inspiratory flow. Of the available delivery systems, dry powder inhalers are unique as they have an internal resistance, are breath actuated, and are flow dependent. Ideally, the user inhales "forcefully" to generate turbulent energy (determined by an individual's inspiratory flow and the resistance of the device) within the device that disaggregates the powder so that the individual inhales the medication particles into the lower respiratory tract. Because of specific features of dry powder inhalers and the required optimal inspiratory flow, there is an unmet need to identify individuals who are likely or unlikely to benefit from dry powder medications. Peak inspiratory flow, defined as the maximal airflow generated during inhalation against the simulated resistance of a dry powder inhaler, is a physiological measure that has biological plausibility, good test characteristics (repeatability and reliability), and is generalizable. Current evidence supports peak inspiratory flow as a predictive therapeutic biomarker to optimize therapy in both out-patients with COPD as well as those hospitalized for an exacerbation prior to discharge. This approach is consistent with the precepts of precision medicine which considers differences in a person's biology, exposure, and lifestyle to prevent and treat disease.