327 Transition from Cough Variant Asthma to Asthma With Reduced FEV1

BACKGROUND: Cough variant asthma (CVA) is one of the most common causes of chronic cough. It may have been thought to be as a pre-asthmatic condition. Some CVA patients show decreased lung function after diagnosed as a CVA. This study aimed to see differences of clinical characteristics between CVA with preserved FEV1 and CVA with reduced FEV1 after diagnosis of CVA. METHODS: We searched medical records from January 2007 to May 2011. Thousand six hundred sixty two patients were diagnosed as CVA. Among 1662 CVA patients, 284 patients were revisited to hospital with symptom of chest tightness. RESULTS: Among 284, fifty two (18.3%) patients showed reduced FEV1. Mean interval between diagnosis of CVA and reducing of FEV1 was 305.5 days. There was no significant difference of level of PC20 or other pulmonary functional values between FEV1-reduced group and -preserved group. CONCLUSIONS: Only small portion of CVA patients was transformed to asthma with reduced FEV1, and most of CVA still preserved their lung function.