A recent study found that patients with chronic obstructive pulmonary disease (COPD) are more likely to have coronary heart disease (CHD) compared with those without COPD.
A cross-sectional study published in PLoS One found that patients with chronic obstructive pulmonary disease (COPD) were more likely to have coronary heart disease (CHD) than people without COPD. The study also aimed to find a range of factors associated with CHD in patients with COPD and controls.
The study sample came from 2 previous patient-control studies: the MicroCOPD study and the follow-up phase of the GeneCOPD study. The MicroCOPD study was conducted from 2012 to 2015 and the GeneCOPD follow-up took place from 2013 to 2016; the latter included patients with COPD and controls from the first GeneCOPD study in 2003 to 2004. The study sample consisted of 775 participants: 347 patients with COPD and 428 controls.
Patients and controls attended visits at the outpatient clinic at the Department of Thoracic Medicine of Haukeland University Hospital in Bergen, Norway. All participants took lung function assessments. Forced vital capacity and forced expiration volume in 1 second was measured. Pulmonary CT scans were also done.
Mean (SD) age of the patients with COPD and controls was 69.0 (7.9) years and 64.8 (8.5) years, respectively. Patients with COPD were older, less likely to have normal body composition, had smoked more frequently, and were more likely to use both cholesterol and blood pressure lowering drugs. Patients with COPD also had a higher calcium score, emphysema burden, and percentage with diabetes.
The patients had varying categories of COPD according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) critera: 11.2% had GOLD category I, 53.5% had GOLD category II, 25.9% had GOLD category III, and 9.5% had GOLD category IV. Patients with COPD were likelier to have confirmed coronary stenosis compared with patients without COPD (12.6% vs 5.7%), with male sex and age most associated with significant coronary stenosis.
Patients with COPD had a significant increased risk of having a calcium score (CaSc) greater than 100, with an odds ratio (OR) of 1.68 (95% CI, 1.12-2.53), with prevalence associations of male sex, age, and statin use. There were 55.9% of patients with COPD who had a CaSc value greater than 100 compared with 31.6% of the controls.
Patients with COPD had an OR of 2.4 (95% CI, 1.35-4.27) for having coronary stenosis on the coronary CT scans; however, after adjustment, the association was reduced and was not statistically significant (OR, 1.80; 95% CI, 0.86-3.78).
There was no statistically significant association between predictors and characteristics among patients with COPD—including GOLD category, emphysema score, and COPD exacerbation frequency—and coronary stenosis or CaSc.
There were some limitations to this study. Causality cannot be established from a cross-sectional study. The study sample size may have been low and there was a chance of type II errors. Not all subjects included in the study had a complete set of the CT scans. The study population may have had a heavier COPD burden than the general population. Finally, CaSc is a surrogate marker for atherosclerosis in the coronary arteries; a CaSc score of zero does not fully exclude the presence of significant coronary stenosis in patients with chest pain syndrome.
The researchers concluded that the current study findings confirm the risk of patients with COPD having CHD but did not identify specific phenotypes at risk.
Svendsen CD, Kuiper KKJ, Ostridge K, et al. Factors associated with coronary heart disease in COPD patients and controls. PLoS One. 2022;17(4):e02265682. doi:10.1371/journal.pone.0265682