Links Between COPD and Hepatitis C

Editor's Note: This article, written by Respiratory Therapist John Bottrell, was originally published on our sister community COPD.net.

Hepatitis C is generally not listed as a COPD comorbidity. However, researchers have spotlighted an increased COPD rate among the hepatitis C population. There’s also an elevated rate of hepatitis C among the COPD population. So, could this be a coincidence? Or are there actual links between these two diseases? Here is some of what researchers are learning.

What does the research show?

Hepatitis is an inflammation of your liver. It's a disease of the liver. Hepatitis C is a virus that causes hepatitis. So, hepatitis C Virus (HCV) refers to the virus and the disease it causes.

Studies are limited in this area. However, here’s what the ones that exist show:¹

• One study showed that 8% of those living with COPD have HCV.
• Of that 8%, 44.4% had risk factors for HCV exposure. These include blood transfusions, surgery, dialysis, etc. This is compared to 12.1% of people living with COPD who do not have HCV.
• One study showed that 34.7% of people with HCV had a lower FEV1. You can read about FEV1 in our COPD.net article “What is Pulmonary Function Testing?”. Simply put, FEV1 is an indicator of lung function and can help with the diagnosis of COPD.
• One study showed that loss of lung function correlated with the extent of liver damage that was done due to hepatitis.
• Of those diagnosed with HCV, 17.6% have COPD. This is much higher than people in the general population.
• Of those diagnosed with HCV, 14.7% have asthma. This is much higher than people in the general population.

These are just a few of the study results thought they tend to show a link between both diseases.

Why might HCV contribute to COPD?

Researchers are not really sure that there truly is a link. Although one theory may be systemic inflammation. COPD is the result of your immune system. It’s a response to something harmful that you inhaled, such as cigarette smoke. This response results in the release of inflammatory chemicals. This is what causes inflammation of your lung tissue. It’s what gradually causes lung damage and a diagnosis of COPD.

These inflammatory chemicals are also suspected of getting into your blood system. A name for this is systemic inflammation. These chemicals may irritate other systems in your body. It is this, so the theory goes, that may explain COPD comorbidities. A comorbidity is a disease that may exist alongside COPD, such as hypertension (high blood pressure), heart disease, anxiety, depression, etc.

HCV may also cause systemic inflammation. Chemicals may travel through your blood system to your lungs. So, this systemic inflammation may cause inflammation of lung tissue. Over time this may lead to the loss of lung function (declining FEV1) in some people which could result in an eventual diagnosis of COPD.

There is one particular inflammatory chemical that may be involved here. The one I’m thinking of is Interleukin 8 (IL8). This has been linked with the type of airway inflammation in COPD. It has also been linked with liver inflammation in HCV.

Other considerations

Keep in mind that this systemic inflammation theory is just one theory. Also, keep in mind that I have simplified this to make a complex process easy to understand. There are other theories to explain the potential link. I won’t get into these here. I just wanted to make the point that there is a potential link.

Does COPD cause HCV?  I do not believe researchers think COPD would directly cause HCV. However, some people with COPD may be exposed to risk factors for catching the virus. Such risk factors are surgery, blood transfusions, or dialysis. Those procedures are generally considered safe. Still, the risk is there.

Again, the link might just be a coincidence. Still, there is enough of a link to merit further studies. Is COPD responsible for the link? If so, better strategies may be necessary to decrease the risk. Is HCV responsible for the link? If so, perhaps strategies are needed to help screen HCV patients for COPD.