PEOPLE suffering from a group of smoking-related lung diseases are less likely to die if they take a particular drug every day, a study has found.

The study said this drug is the only one shown to have improved the survival rate of patients with chronic obstructive pulmonary disease (COPD).

In the four-year study, patients who took the drug, called tiotropium, had their risk of dying reduced by 16 per cent, compared to those who did not.

The drug also relieved patients' symptoms and improved their quality of life.

Patients on the drug had the functioning ability of their lungs improve by 10 per cent; those who did not take it did not show improvement.

They also suffered from 14 per cent fewer attacks of breathlessness a year, and were 14 per cent less likely to require hospitalisation from such attacks.

More than 5,000 patients from 37 different countries, including 36 patients from Singapore, took part in the study.

On top of their usual medication, about half of the patients took the drug, while the rest were given a placebo.

In Singapore, about 60,000 people suffer from COPD, a group of lung diseases which usually results from smoking, including chronic bronchitis and emphysema.