[Pulmonary age-chronological age relation as indicator of improvement and severity of patients with bronchial asthma]

Spirometry is a very useful clinical test to evaluate pulmonary function in asthmatic patients. However, pulmonary function could be affected by the sex, time of clinical evolution, lung age (LA) and chronological age (CA).

To evaluate LA/CA as index of clinical improvement or severity in asthmatic patients.

A prospective study was done where asthma severity was evaluated according to GINA classification. Spirometry was performed at the beginning of this study, at 46, 96, 192 days and after 10 months. Statistical analysis was performed using t test, two-way ANOVA test, correlation and multiple regression models as well as ROC curves were also performed, a p<0.05 was considered significant.

Seventy asthmatic patients were included (22 male and 48 female), mean CA was 35-years; mean LA was 48-years with a LA/CA index=1.4, time of clinical evolution was 13 years. A LA/CA index=1 (range 0.5 to 0.9) was observed in asymptomatic patients. LA/CA index over 1 were related with airway inflammation, and a LA/CA index higher than 2 correlated with GINA step 3. Interestingly when we analyzed CA and LA, we observed in female group a higher than 10 years difference between CA and LA (GINA step 2 and 3); while in male we observed (GINA step 1, step 2 and step 3). LA/CA index less than or equal to 1 was considered normal.

LA/CA index could be used as clinical indicator of clinical improvement or severity in asthma patients in both, male and female, with excellent correlation of pulmonary function and age.