Some BP drugs likely to increase lung cancer risk

Some drugs widely prescribed for treating high blood pressure could be associated with an increased risk of lung cancer by almost a third, claims a research.

The study, led by Professor Laurent Azoulay at McGill University in Canada, found that angiotensin converting enzyme inhibitor drugs (ACEIs) to lower blood pressure are associated with an increased risk of lung cancer compared with the use of another group of blood pressure drugs called angiotensin receptor blockers (ARBs).

The risk is particularly elevated among people using ACEIs for more than five years and increased 31 per cent in patients who used ACEIs for more than 10 years.

The drugs work by blocking an enzyme which narrows blood vessels, and raises blood pressure.

Although the magnitudes of the observed estimates are modest, the researchers point out that ACEIs are one of the most widely prescribed drug classes, "so these small relative effects could translate into large absolute numbers of patients at risk".

To understand the association, published in the journal The BMJ, the team analysed primary care records for nearly one million patients who started taking a new antihypertensive drug between 1995 and 2015.

Patients were at least 18 years of age, with no previous cancer, and were followed up for an average of 6.4 years, during which 7,952 cases of lung cancer were identified (a rate of 1.3 per 1,000 persons).

After taking account of factors that could potentially influence the findings, including age, sex, weight (BMI), smoking status, alcohol related disorders, and history of lung diseases, use of ACEIs was associated with an overall 14 per cent increased risk of lung cancer.

Earlier the researchers estimated that the risk of lung cancer could be through the build-up of protein-like chemicals called bradykinin and substance P in the lung.

These chemicals have been found on lung cancer tissue, and bradykinin may directly stimulate the growth of lung cancer.

However, previous observational studies examining this association are limited and report inconsistent results.