Patients with lung disease are more likely to develop heart disease independent of any risk factors, according to new research.

A new study published in Orphanet Journal of Rare Diseases looked at patients who have a rare genetic condition called Alpha-1 antitrypsin deficiency (AATD) which causes lung disease similar to COPD independently of any risk factors such as smoking or age. 

More than 220 patients with AATD were recruited to the study alongside patients with COPD and a control non-lung disease population. All were assessed for present cardiovascular disease and recognized risk factors, including assessment of vascular stiffness known to increase risk for future events. Patients were then tracked for four years to see whether they developed cardiovascular disease.

The patients with the rare genetic condition AATD had the highest adjusted scores among all participants for vascular stiffness but had the lowest scores for standard associated risk factors of cardiovascular disease, and nearly half (45%) of patients had discordant scores where one was high and the other low.

Meanwhile, COPD and control participants had similar scores across the direct and indirect measures of cardiovascular disease risk.

Furthermore, despite the AATD participants having lower risk factors associated with developing cardiovascular disease including being younger and a higher proportion who had never smoked, 12.7% of participants developed cardiovascular disease after four years of follow-up.

“This long-term study has enabled us to see the relationship between lung disease and heart disease in a unique way by following a group of patients with this rare genetic disease,” says Robert Stockley, professor and consultant in acute and respiratory medicine at the University of Birmingham and senior author of the paper, in a release. “Our study has shown that there is an increased risk for people with lung conditions of going on to develop cardiovascular conditions and that only looking at conventional factors such as age and smoking doesn’t give the full picture of the relationship between these two essential systems in the body.”

Potential Target for Treatment

Participants also gave blood which was tested for an enzyme linked with lung damage in AATD patients.

There were significantly higher levels of the enzyme Proteinase 3 in the AATD patients, but the study found that there was a link between elevated levels of the enzyme and vascular stiffness and, hence, cardiovascular disease risk. 

The team believes that the Proteinase 3 enzyme may have a more direct impact on the development of heart and lung disease through the breakdown of fibers that support the large arteries and lungs and that Proteinase 3 inhibitors could be a novel therapeutic to prevent cardiovascular disease, especially in AATD patients.

“The role of Proteinase 3 acts as a powerful link between lung and heart disease. The action that the enzyme has in attacking elastin fibers found in the lungs and major arteries suggests that inhibiting its action could have a dual effect to slow both lung and cardiovascular diseases,” says Louise Crowley, clinical research fellow and PhD researcher at the University of Birmingham and corresponding author of the paper, in a release.

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