Rate of change of FEV1 and VC in adults with chronic airflow obstruction

We have investigated the rate of change in post-bronchodilator FEV 1 and VC in patients with chronic airflow obstruction by retrospective analysis of data in our clinical database. One thousand and forty-four patients (633 females) fulfilled the study criteria, namely two sets of measurements with a minimum of six calendar months between measurements. Measurements of FEV 1 and VC were made before and 20 minutes after administration of 2.5 mg nebulised salbutamol. Only patients with an FEV 1 /VC ratio below the lower limit of normal after administration of 2.5 mg nebulised salbutamol were included in the study. Rate of change in FEV 1 was calculated in litres/year. Smoking status (smoker, ex-smoker or non-smoker) was recorded at each visit, but the number of cigarettes smoked was not recorded. Patients were only identified as smokers if the same status was recorded at both measurements. The rate of change in post salbutamol FEV 1 and VC in all patients and in the subgroup of smokers are shown in Table 1. Values shown are mean ± SD. The rate of change in FEV 1 and VC in patients is significantly higher in males when compared to females. Males who continue to smoke have a greater rate of change in both FEV 1 and VC than females who smoke. Further investigation into these gender differences is warranted.