Background
Risk of exacerbations in individuals with mild chronic obstructive pulmonary disease (COPD) in the general population is less well described than in more advanced disease. We hypothesized that in addition to history of previous exacerbation also other clinical characteristics predict future moderate exacerbations.

Methods
In 96,462 individuals in the Copenhagen General Population Study, we identified 3175 with clinical COPD defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.70 and FEV1 <80% predicted in symptomatic individuals without asthma. We estimated the importance of age, sex, FEV1, modified Medical Research Council (mMRC) dyspnea scale, chronic bronchitis, exacerbation history, comorbidities, cohabitation, body mass index, smoking, and blood eosinophils for the 1-year and 3-year future risk of moderate COPD exacerbations and developed a prediction tool for future exacerbations in COPD in the general population based on easily available clinical information.

Results
We observed 265 exacerbations in 2543 maintenance treatment naïve individuals with COPD and 197 exacerbations in 632 individuals with COPD on maintenance treatment. In the maintenance treatment naïve group, exacerbation history (hazard ratio (HR): 8.53), low FEV1 (HR: 4.82 for <30% predicted versus 50–79% predicted), and higher age (HR: 1.46 for ≥75 years versus <65 years) were significant predictors of future exacerbations. In the group on maintenance treatment, male sex and mMRC ≥2 also predicted higher risk with borderline significance.

Conclusions
In addition to exacerbation history also higher age and lower FEV1 predict future exacerbation risk in COPD in the general population.