Chronic obstructive pulmonary disease was associated with an increased risk of cerebral microbleeds – a marker of cerebral small vessel disease – independent of factors such as age, sex, smoking status, and cholesterol levels, according to a prospective, population-based cohort study.
"Depression, postural instability, cognitive and functional impairment are known consequences of cerebral small-vessel disease, and are frequently described extrapulmonary manifestations in patients with COPD," wrote Dr. Lies Lahousse from Ghent University Hospital, Belgium, and colleagues. "However, it is unclear whether COPD is associated with incident cerebral small-vessel disease."
Patients with COPD had a significantly higher prevalence of cerebral microbleeds, compared with patients with normal lung function, even after accounting for age, sex, smoking status, atherosclerotic macroangiopathy, antithrombotic use, total cholesterol, triglycerides, and serum creatinine (odds ratio, 1.7; 95% confidence interval, 1.15-2.47; P = .007).
Patients with COPD also had a more than threefold increase in the prevalence of microbleeds in deep or infratentorial locations (OR, 3.3; 95% CI, 1.97-5.53; P less than .001), according to data published online July 19 in the American Journal of Respiratory and Critical Care Medicine.
When a longitudinal analysis was conducted in patients without microbleed at baseline, COPD independently predicted a sevenfold increase in risk of deep or infratentorial microbleeds (OR, 7.1; 95% CI, 2.1-24.5; P = .002) over a median time interval of 3.42 years.
"Our results are in line with two previous cross-sectional studies that showed that patients with COPD had a significantly increased volume of cerebral white matter lesions, which is another marker of cerebral small vessel disease, and known to be associated with microbleeds in a deep or infratentorial region," Dr. Lahousse and associates said.
Although the increased incidence of microbleeds in patients with COPD was independent of smoking status, the researchers did find a significantly higher prevalence of cerebral microbleeds among individuals who had smoked.
The study involved 165 patients with COPD and 645 patients without COPD who were enrolled in the Rotterdam Scan Study, a population-based cohort study using MRI scan to examine age-related brain changes.
Previous research had shown an increased prevalence of atherosclerotic macroangiopathy in patients with COPD, but that was taken into account in the analysis.
The authors therefore suggested that COPD may affect large and small blood vessels, and that stiffening of arteries and arterioles may be the result of systemic inflammation in COPD as well as hypoxia caused by airflow limitation.
"Although severity of airflow limitation may not entirely reflect disease activity, our results suggest that cerebral small vessel disease is more present in COPD patients with more severe airflow limitation," the investigators noted.
Given the potential cognitive and functional consequences of microbleeds, the study authors suggested that the results could help with identification of vulnerable patient groups and point to the need for more research into preventive strategies.
The study was funded by the Fund for Scientific Research Flanders project and the Netherlands Organization for Scientific Research.