Study objectives: There is increasing interest in the frequency and nature of comorbidities in patients with obstructive lung disease: COPD and asthma. We aimed to quantify baseline rates of comorbidities in COPD and asthma patients and to compare the risks to the general population.
Design, setting, and participants: Within the UK General Practice Research Database, we compared incident patients with COPD (n = 2,699) and asthma (n = 7,931) physician diagnosed in 1998 with age, gender, time, and practice-matched cohorts. Rates were calculated and relative risks (RRs) were estimated for comorbidities in major organ systems and selected medical events of a priori interest.
Measurements and results: In both COPD and asthma, the total sum of diagnoses related to major organ systems was higher than in their matched population controls. Among incident COPD patients, a frequency > 1% within the first year after diagnosis was observed for angina, cataracts, bone fractures, osteoporosis, pneumonia, and respiratory infections, the highest being angina with 4.0%. Compared to the non-COPD cohort, COPD patients were at increased risk for pneumonia (relative risk [RR] = 16.0), osteoporosis (RR = 3.1), respiratory infection (RR = 2.2), myocardial infarction (RR = 1.7), angina (RR = 1.7), fractures (RR = 1.6), and glaucoma (RR = 1.3) [all p < 0.05]. Of note, 2.0% of COPD patients had cataracts recorded, but this rate was no different than that of the non-COPD cohort (RR = 0.9). Among incident asthma patients, the occurrence of events was generally lower, likely due to the younger age distribution, except for 4.0% with respiratory infection (RR = 1.84) and 1.7% with fractures (RR = 1.5). Angina prevalence was 0.7% in the asthma cohort and 1.4 times more common than in patients without asthma.
Conclusion: COPD and asthma are conditions associated with many comorbidities, albeit asthma to a lesser extent than COPD, which had not been systematically reviewed before. Baseline rates of cardiovascular-, bone-, and other smoking-related conditions are high.