Common painkillers may hide major risks, says a new study.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to alleviate pain.
In fact, according to the National Institutes of Health (NIH), about 30 million people in the United States take NSAIDs each year.
However, due to ethical concerns, these risks cannot be evaluated in clinical trials.
The European Society of Cardiology therefore carried out an extensive review of existing research that concluded that nonaspirin NSAIDs should not be prescribed to individuals at high risk of heart disease, nor should they be sold over the counter without issuing an "appropriate warning of their frequent cardiovascular complications."
Now, a new study focuses on one NSAID in particular: diclofenac. Scientists led by Morten Schmidt, at Aarhus University Hospital in Denmark, set out to investigate the cardiovascular risks of taking this common painkiller, which some rank as "the most widely used [...] NSAID in the world."
Schmidt and team examined 252 national studies for information on over 6.3 million Danish people over a period of 20 years in 1996–2016. On average, the participants were aged 46–56.
During the study period, the researchers examined the cardiovascular risks of taking up diclofenac and compared them with the risks of starting paracetamol, ibuprofen, or naproxen.
After accounting for potentially confounding factors, the researchers found that within 30 days of taking up diclofenac, the rate of major cardiovascular problems — such as arrhythmia, ischemic stroke, heart failure, and heart attack — was much higher compared with other NSAIDs.
Specifically, the risk of such adverse cardiovascular events was 50 percent higher among those who started taking diclofenac, compared with those who did not take it. Compared with taking paracetamol or ibuprofen, taking diclofenac raised cardiovascular risk by 20 percent.
Additionally, write the authors, "Diclofenac initiation [...] increased the risk of upper gastrointestinal bleeding [...] by approximately 4.5-fold compared with no initiation [and] 2.5-fold compared with initiation of ibuprofen or paracetamol."
The cardiovascular threat also increased with the risk at baseline. In other words, the higher the risk of heart problems when the patients started taking the drug, the higher the risk of actually developing heart problems over the course of the treatment.
"Diclofenac poses a cardiovascular health risk compared with non-use, paracetamol use, and use of other traditional nonsteroidal anti-inflammatory drugs," explain the authors.
Although the study is observational, they say — which means that no conclusions can be drawn about causality — the large sample size and the quality of the research is sufficiently "strong evidence to guide clinical decision-making."
"Treatment of pain and inflammation with NSAIDs," explain the authors, "may be worthwhile for some patients to improve quality of life despite potential side effects."
"Considering its cardiovascular and gastrointestinal risks, however, there is little justification to initiate diclofenac treatment before other traditional NSAIDs."