Chronic obstructive pulmonary disease in UK primary care: incidence and risk factors

We evaluated the association of chronic obstructive pulmonary disease (COPD) with modifiable risk factors such as smoking and prescription medications, and investigated possible risk factors unique to patients who had never smoked. The UK General Practice Research Database was used to identify a cohort of patients with a first diagnosis of COPD (n = 1927) along with age- and sex-matched controls without COPD (n = 16 546). The incidence of COPD diagnoses and the risks associated with medication use, co-morbidities, and demographic factors, were estimated. The incidence of COPD was 2.6 per 1000 person-years (95% confidence interval [CI]: 2.5-2.7) among 40-89 year-olds. The risk significantly increased in current and former smokers (OR: 6.15 [95% CI: 5.41-7.00] and 3.45 [95% CI: 2.96-4.02]), respectively. The risk was significantly lower in former smokers than current smokers (OR: 0.61; 95% CI: 0.52-0.71). Current statin use was significantly associated with a reduced risk (OR: 0.45; 95% CI: 0.25-0.80). In never smokers, risk factors included advanced age and obesity. The risk in never smokers was more strongly related to paracetamol use (OR: 1.82; 95% CI: 1.33-2.49) than in current and former smokers (OR: 1.48; 95% CI: 1.18-1.86). In summary, COPD is associated with a range of cardiovascular and respiratory conditions and the risk is influenced by current and past medications. While the risk factors are similar in smokers and never smokers, some were unique to never smokers. Moreover, subjects who stopped smoking had a substantially lower COPD risk than those who continued smoking.