The epidemiology of the frequent exacerbator (FE) phenotype is limited in patients with a mild-grade of the disease, because they usually are not included in epidemiological studies. Our objective was to study predictors of FE in mild-grade COPD patients in comparison with more severe COPD patients.

We conducted a retrospective population-based cohort study including 723 patients with confirmed COPD and FEV1 data available. Exacerbation frequency was observed for the previous year and the following year. Patients were defined as FE phenotype if they suffered ≥ 2 exacerbations in a year and were categorized according to severity of COPD: GOLD grade 1 (≥ 80%), grade 2 (≥ 50–80%), grade 3 (≥ 30–49.9%), grade 4 (< 30%). Odds ratios (OR) and their 95% confidence intervals (95% CI) were estimated by logistic regression adjusting for age, gender and smoking status.

Seventy-five out of the 723 patients (10.4%) were classified as FEV1-mild-GOLD grade 1 patients; 433 (59.9%) were FEV1-moderate-GOLD grade 2; 190 (26.3%) severe-GOLD grade 3 and 25 patients (3.5%) very severe-GOLD grade 4. The main predictor of being FE among all grades of COPD severity, was a history of frequent exacerbations the previous year: crude odds ratios: 5.87, 4.73, 6.32 and 4.00 for GOLD grades 1, 2, 3 and 4, respectively. In the multivariable analysis, association in mild-GOLD grade 1 patients strengthened: adjusted OR: 15.90 (95% CI: 3.22–78.59), whereas in the rest of patients associations range from 4.20 to 6.58.

The FE phenotype susceptibility seem to be also important in patients with milder disease (GOLD grade 1), supporting a reconsideration of a more in-depth monitoring and treatment.