Thousands of arthritis patients could have a hidden deadly lung disease, a study has claimed.

Rheumatoid arthritis, an autoimmune condition that affects more than 400,000 people in the UK, is best known for causing joint pain and inflammation.

But new research has linked it to a serious complication: rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

This can cause severe scarring and inflammation in the lungs, making it hard to breathe.

An international expert consensus statement, published in medical journal The Lancet Respiratory Medicine, has identified the key risk factors for developing RA-ILD.

'Rheumatoid arthritis doesn't just affect the joints, it can also affect the lungs in ways that can significantly impact a person's health and quality of life,' said Dr Joshua Solomon, lead author of the study and director of interstitial lung disease at National Jewish Health.

One in six rheumatoid arthritis patients will develop some sort of lung abnormality, research shows. One in ten will get RA-ILD.

If caught early, it can be treated with medications that control inflammation, slow lung scarring and preserve breathing.

Common therapies include immunosuppressant drugs as well as anti-fibrotic medications, which work to preserve lung function.

When caught late the disease can lead to more severe outcomes and ultimately be deadly.

Symptoms include an unexplained, persistent dry cough and shortness of breath during physical exertion, as well as general fatigue and weakness.

Other, rarer, signs of the disease include velcro-like crackles in the lungs, clubbing of the fingers and toes and a hoarse voice.

Being male, over 60 and having a history of smoking can all raise the risk of RA-ILD. Having more severe rheumatoid arthritis symptoms can also contribute to its development.

To address this, experts say, more patients should be screened for the condition if they match high-risk criteria.

'These recommendations provide practical guidance to help clinicians identify lung disease earlier, monitor patients more effectively and determine when treatment may be appropriate,' said Dr Solomon.