Objective To study the clinical application of the GOLD/GINA criteria and the Spanish guideline in the diagnosis of asthma-COPD overlap syndrome (ACOS). Methods Patients with stable COPD were consecutively enrolled in the study. Clinical data were collected, lung function with bronchodilator test and peak expiratory flow (PEF) were performed, and peripheral blood eosinophils, total IgE, and sputum inflammatory cells were measured. Those overlap with asthma were identified by the 2 different criteria, and the prevalence and features of ACOS were compared. Results Among 104 cases of stable COPD, 24 (23.1%) and 10 (9.6%) were identified as ACOS by the GOLD/GINA criteria and the Spanish guideline, respectively; the latter 10 cases were all included in the former 24. For the GOLD/GINA criteria, the most common features were symptoms triggered by exercise or emotions, variable airflow limitation, family history of asthma, and other allergic conditions. Mean diurnal PEF variation≥10% was evident in 11 cases (45.8%, 11/24), while bronchodilator test was positive in 16 cases (66.7%, 16/24). For the Spanish guideline, the most common features were diagnosis of asthma before 40, other allergic diseases, positive bronchodilator test on 2 occasions. Conclusions The GOLD/GINA criteria may be more sensitive for the diagnosis of ACOS, and do not need sophisticated lab tests, which may be more applicable for clinical use. The Spanish guideline is restrictive, and therefore may lead to under-diagnosis.
Objective To evaluate if the difference between slow vital capacity ( VC) and forced vital capacity ( FVC) could be used to predict severity of airflow limitation in patients with stable chronic obstructive pulmonary disease ( COPD) . Methods VC and FVC were measured in 200 patients with COPD [ 159 males;mean FEV1 , ( 49.31 ±15.75) % of predicted] and 114 healthy controls [ 64 males; mean FEV1 , ( 99.67 ±13.62) % of predicted] . Results The difference between VC and FVC ( VC - FVC) , which showed a negative correlation with FEV1 of predicted ( r=- 0.412, Plt;0.001) , was significantly larger in the COPD patients than that in the controls [ ( 145.40 ±157.50) mL vs. ( 21. 10 ±61. 30) mL, Plt; 0. 001] . The FVC/VC ratio was significantly lower in the COPD patients than that in the controls [ ( 93. 61 ± 7. 10) % vs. ( 99.27 ±2.24) % , P lt; 0.001] , and was positively correlated with FEV1 of predicted in the COPD patients ( r =0.517, P lt;0.001) . There was significant difference in VC - FVC in the COPD patients with FEV1≥50% of predicted ( 5 patients in GOLD level 1 and 74 patients in GOLD level 2) and those patients with FEV1 lt;50% of predicted ( 106 patients in GOLD level 3 and 15 patients in GOLD level 4) [ ( 78.23 ±108.26) mL vs. ( 189.26 ±169.21) mL, P =0.003] . Conclusion The difference between VC and FVC and the FVC/VC ratio, which are more easily obtained from spirometric test, are able to detect severity of airflow limitation in patients with stable COPD.