Objective: To determine the clinical impact of Thai Asthma Guideline implementation.
Material and Method: A nationwide written questionnaire survey was used for 365 Thai physicians who were involved in routine asthma practice. The questionnaire consisted of two questions; the first concerning the criteria to define steps of asthma severity (16 parameters) and the second concerning controller use in each step of asthma severity, focusing on the use of inhaled corticosteroids (ICS).
Results: Of 272 physicians (74.5%) who responded to the questionnaire; 21, 76 and 175 were chest physicians, general practitioners (internists), and general doctors, respectively. All the non-responders could not provide answers to the questionnaire because they were unable to remember them all. More than 12 out of 16 parameters in the first question were filled out correctly by only 14%, 4% and 5% of chest physicians, general practitioners and general doctors, respectively, whereas fewer than 5 out of 16 parameters were answered correctly by 33%, 66% and 71% of these physicians, respectively. The most common parameters answered incorrectly by general doctors were FEV1 and PEF variability. ICS was the most common controller used in controlling each step of persistent asthma. However, only 46.8% of general doctors prescribed it for the management of mild persistent asthma.
Conclusion: The Thai Asthma Guideline is impractical for clinical practice implementation, due to complicated severity grading and a very low rate of lung function tests for grading asthma severity. Although ICS is the most common controller prescribed, its use is still far from optimal in Thailand. The authors suggest that the Thai asthma guideline should be simplified and aimed towards optimal ICS use among generalists.

Keywords: Asthma, GINA guideline, Implementation, Inhaled corticosteroids, Thai Asthma guideline