Joannie Shen; Michael Johnston; Ron D Hays


Expert Rev Pharmacoeconomics Outcomes Res. 2011;11(4):447-453. 

In This Article


Diaries can be useful for minimizing recall bias and documenting symptoms while patients are using medications in their day-to-day life.[15,16] 'Symptom-free days' is a useful diary variable, but it is not responsive to change among those at the extremes with either very frequent or infrequent symptoms. In addition to symptoms, ambulatory peak expiratory flow (PEF) measurements can be recorded in dairies. PEF provides an objective measure of airway obstruction and is one of the most commonly reported asthma outcomes. However, PEF is inferior to the forced expiratory volume (FEV) in 1 s (FEV1) as a measure of airways obstruction because PEF underestimates airway obstruction in patients with airway remodeling. Diaries can also be used to record inhaler use for prophylactic or rescue use.


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