Diabetes mellitus among outpatients with COPD attending a university hospital

Type 2 diabetes mellitus is a common comorbidity of COPD, but there are still many doubts about the relation among diabetes and COPD. We retrospectively collected data from patients afferent to our Respiratory Diseases outpatient clinic at the Tor Vergata University Hospital between 2010 and 2012. The study population was analyzed by clusters of age, gender, body mass index (BMI), smoking status, lung function, concomitant pharmacologic therapies and comorbidities. The values of the association between variables were expressed as odds ratio. Data were adjusted for gender, age and possible confounding variables by Mantel-Haenszel method. We identified 493 patients with COPD. Ninety-two (18.7 %) patients were affected by type 2 diabetes mellitus, with no significant gender differences. The prevalence distribution was similar among the different age clusters, but the association was stronger in patients younger than 65 years. The association was present only in obese subjects in whom it was significant only in patients with moderate-to-severe COPD, but not mild COPD. The presence of cardiovascular diseases was significantly associated with diabetes mellitus in patients with COPD. There was a slight association of inhaled corticosteroid (ICS) use with the presence of diabetes mellitus in COPD, but the combination of an ICS with a β2-agonist apparently reduced this association. The association with type 2 diabetes mellitus was greater in patients with COPD respect to general population, and correlated with the increase in BMI and the presence of other comorbidities, suggesting that both diseases may be targets of systemic inflammation.