To investigate whether there is a significant relationship between an increased frequency of exacerbations and the rate of forced expiratory volume in 1s (FEV₁) decline in COPD patients.

About 102 COPD patients (44 smokers, 58 ex-smokers) participated in a 3-year prospective study. Exacerbations were identified as worsening of patient’s respiratory symptoms as recorded on diary cards. Spirometry was performed every 6 months. The effect of frequent exacerbations on lung function was investigated using random effects models.

The median (mean(95% CI)) annual exacerbation rate was 2.85 (3.1 (2.7–3.6)). Patients with an annual exacerbation rate over the median rate had significantly lower baseline post-bronchodilation FEV₁(%pred), higher MRC dyspnoea score and chronic cough compared to patients who had an annual exacerbation rate less than the median. The average annual rate of FEV₁(%pred), adjusted for smoking decline (ΔFEV₁), was found significantly increased in frequent compared to infrequent exacerbators ( ). The highest ΔFEV₁ was observed in smokers frequent exacerbators and a significant interaction between exacerbation frequency and ΔFEV₁ was also observed in ex-smokers.

Our findings suggest that an increased frequency of exacerbations is significantly associated with FEV₁ decline even in ex-smokers. Thus, smoking and frequent exacerbations may have both negative impact on lung function. Smoking cessation and prevention of exacerbations should be a major target in COPD.