Diclofenac Linked to Increased Cardiovascular Health Risks

A traditional non-steroidal anti-inflammatory drug (NSAID) called diclofenac poses a cardiovascular health risk compared with no use, paracetamol use, and use of other traditional NSAIDs, according to a study led by Aarhus University Hospital researchers.

Diclofenac is associated with an increased risk of major cardiovascular events. Image credit: Petr Vnukko.

Diclofenac is a NSAID for treating pain and inflammation and is widely used across the world. But its cardiovascular risks compared with those of other traditional NSAIDs have never been examined in large randomized controlled trials.

So Aarhus University Hospital’s Dr. Morten Schmidt and colleagues examined the cardiovascular risks of starting diclofenac compared with no NSAIDS, starting other traditional NSAIDs, and starting paracetamol.

The results are based on national registry data for more than 6.3 million adults in Denmark with at least one year of continuous prescription records before study entry in January 1996.

Participants were split into low, moderate, and high baseline cardiovascular risk. Average age was 46-49 years among participants starting NSAIDs and 56 years among those starting paracetamol.

After taking account of potentially influential factors, starting diclofenac during the study period (1996-2016) was associated with an increased rate of major adverse cardiovascular events within 30 days compared with starting other traditional NSAIDs (ibuprofen or naproxen) or starting paracetamol.

Events included irregular heart beat or flutter, ischemic stroke, heart failure, and heart attack. The increased risks applied to men and women of all ages and also at low doses of diclofenac.

Starting diclofenac was also associated with an increased rate of cardiac death compared with no NSAIDs, and an increased risk of upper gastrointestinal bleeding compared with no NSAIDs, starting ibuprofen or paracetamol, but not with naproxen.

Although the relative risk was increased, the absolute risk remained low for the individual patient.

When results were analyzed by baseline cardiovascular risk, the absolute number of events per 1,000 diclofenac starters per year also increased.

“Treatment of pain and inflammation with NSAIDs may be worthwhile for some patients to improve quality of life despite potential side effects,” Dr. Schmidt and co-authors said.

“Considering its cardiovascular and gastrointestinal risks, however, there is little justification to initiate diclofenac treatment before other traditional NSAIDs.”

The results appear in the journal BMJ.

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Morten Schmidt et al. 2018. Diclofenac use and cardiovascular risks: series of nationwide cohort studies. BMJ 362: k3426; doi: 10.1136/bmj.k3426