Current guidelines by the National Institute for Health and Clinical Excellence (NICE) recommend treatment with angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) for conditions such as hypertension,1 chronic heart failure,2 and proteinuric chronic kidney disease.3 In England, the prescription of these drugs has increased by 15.8% over the past four years.4 Because ACE inhibitors and ARBs are often coprescribed with non-steroidal anti-inflammatory drugs (NSAIDs) and diuretics, particularly in older people,5 we need to know more about the safety of such combinations.

In a linked paper (doi:10.1136/bmj.e8525), Lapi and colleagues used a large database that was representative of UK primary care to examine data on 487 372 patients taking antihypertensive drugs.6 They used a nested case-control design to examine whether adding an NSAID to an ACE inhibitor, ARB, or diuretic in double or triple therapy combinations increased the risk of subsequent hospital admission with acute kidney injury. Acute kidney injury is seen in more than …