Evaluation of spirometric parameters in chronic airway diseases

Spirometry is the most commonly used repeatable pulmonary function test in the diagnosis and monitoring of lung diseases. Forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and FEV1 / FVC ratio are parameters that can be measured by spirometry and provide information about airway diseases. International guidelines have published standardization criteria for evaluating spirometric parameters. However, the test performed is dependent on the patient's effort and requires the patient's compliance while performing the test. The aim of this study is to develop physiological parameters related to airway diseases using spirometry measurements and to compare these parameters with existing spirometric parameters. In our study, the data of 12,326 spirometry tests were analyzed using mathematical modeling and newly defined parameters were examined with ROC curves. In the model, the area under the curve (AUC) was found to be 0.988 (95% confidence interval (CI) 0.986-0.990), (sensitivity (Se) 95% and specificity (Sp) 95%) for t2; 0.986 (95% CI 0.984-0.988) (Se 97%, Sp 92%) for t3; 0.929 (95% CI 0.922-0.935) (Se 88%, Sp 84%) for t4; 0.881 (95% CI 0.872-0.890) (Se 78%, Sp 82%) for t1 geometric mean (gmean); 0.849 (95% CI 0.839-0.859) (Se 75%, Sp 79%) for tp gmean; 0.912 (95% CI 0.905-0.919) (Se 85%, Sp 82%) for tq gmean (p<0.001 for all measurements). The t2 and t3 parameters were found to be more specific and sensitive than the maximal mid-expiratory flow (MMEF25-75%) value in detecting airway obstruction. Our research has shown that these parameters have a strong relationship with airway obstruction.