Unbalanced and poorly researched health reporting is often criticised for the effect it can have on people’s health choices. That effect can be very difficult to quantify, but a paper published this week in the Medical Journal of Australia estimates that an extra 28,000 Australians stopped taking cholesterol-lowering statins after an Australian Broadcasting Corporation (ABC) documentary.

Statins are widely-prescribed drugs that are used to lower the levels of dangerous LDL cholesterol in the blood. According to the Australian government’s most recent estimate (PDF), they were the most commonly prescribed drug in Australia in 2011. Any change in the number of people taking statins therefore has a huge impact, affecting thousands of people.

Fodder for alarmism

Statins are associated with a range of side effects, mostly minor but some more severe. That makes them an ideal subject for sensationalist reporting. The association between statins and an increased risk for diabetes recently made headlines, despite the fact that this risk was already well-established.

The “increased risk of 50 percent” reported widely would be better expressed as an increase from two people out of 200 with diabetes to three people out of 200, said Stephen Evans, a professor at the London School of Hygiene & Tropical Medicine, in a public statement. There’s also the problem that the same lifestyle factors cause both an increased risk for diabetes and the cardiovascular disease that leads people to need statins. This makes it difficult to be certain that the increase in diabetes risk was definitely caused by the statins.

The range and nature of the side effects mean that each doctor prescribing statins needs to weigh up the costs and benefits. For people who are at high risk for dying from a heart attack or stroke, that risk will outweigh potential concerns about side effects like diabetes.

ABC became concerned that its documentary, The Heart of the Matter, hadn't portrayed the facts well. An investigation concluded that it had breached ABC standards of impartiality, and the programme was withdrawn. However, the investigation report (PDF) emphasizes that the documentary included a disclaimer stating that “the views expressed in the program were not intended as medical advice and they should consult with their doctors regarding medications.” Did people pay attention to this disclaimer?

Abandoned prescriptions

Researchers at the University of Sydney and Australian National University were able to access robust records of how many people filled prescriptions for statins. The records were those kept by Australia’s Pharmaceutical Benefits Scheme (PBS), which subsidizes medicine for all citizens and permanent residents. The researchers took a random, anonymised sample of 10 percent of these records.

Looking simply at how many statin prescriptions were filled before and after the documentary aired in October 2013 wouldn’t necessarily give a very accurate picture, because there are many factors that could affect the number of statin prescriptions in a given month.

One major concern is that there is seasonal variation in all prescriptions in Australia, because the PBS limits how much people are expected to contribute in co-payments every year. The result is that people can get more free prescriptions in November and December. Prescription levels then drop in January and February when people have to pay again.

To guard against these problems, the researchers looked at data from a large time range, starting in July 2009 and ending in June 2014. They could then observe what the normal patterns looked like and how those changed after the documentary was aired. There’s still the possibility that something else could have caused the change, but the wider time range makes it less likely.

To add another level of control, the researchers also looked at the number of prescriptions for proton pump inhibitors (PPIs), which are often prescribed for the same groups of people that use statins. If PPI use changed at the same rate as statin use, that could indicate something other than the documentary causing the change. However, if only statin use changed, that’s another finger pointing at the documentary.

Because people are sometimes just slack about taking their medication, the authors decided to consider someone as having discontinued their statins only if they stopped collecting their prescriptions for at least 105 days. After that period of time had elapsed, the researchers could then trace the data back to the week when that individual first neglected their prescription.

Thousands quit their meds

In the week the documentary aired, the records showed that statin prescriptions dropped by 2.6 percent. Given the size of the population, that was a highly significant result, translating to approximately 14,000 fewer Australians filling their prescriptions. Extrapolating from that week’s results, the researchers estimated that around 60,000 Australians could be affected.

However, there’s also a constant rate of people discontinuing statin use for the range of normal reasons that people have for changing their prescription medication. Before the documentary, 18 people out of every thousand were stopping their statins; after the documentary, that figure increased to 26 people out of every thousand.

Out of the 60,000 estimated Australians who stopped taking statins in that time period, approximately 32,000 would have stopped anyway if the normal pattern had continued. The extra 28,000 people who stopped at that time was a significant increase with the documentary being a highly likely explanation. Many of the people who stopped were in high-risk health groups, taking multiple cardiovascular medications and sometimes diabetes medications too.

Although so many extra people stopped their statins at that time, the rate of discontinuation slowly dropped month by month, returning to its previous average by 18 weeks after the documentary. By contrast, there was no change in how many people stopped taking PPIs after the documentary.

Preventable fatalities

If the estimated 60,000 people who stopped taking statins that October continued along the same path and refused to start taking them again, the result could be a marked increase in the number of strokes, heart attacks, and other related conditions—as high as an extra 2,900 preventable, and potentially fatal, incidents, write the authors.

It’s impossible to say whether it definitely was the documentary that caused the change without finding each individual and asking them what made them stop filling their prescriptions. It’s also important to remember that not all of those 60,000 people are thought to have stopped because of the documentary. However, the evidence does seem to point in the direction of the media scare for approximately half of those cases.

This isn’t to say that the media shouldn’t report critically on health information, said Emily Banks, one of the authors of the paper, in a public statement. “The media has a critical role to play in questioning the status quo and in helping people to make sense of health information. These findings demonstrate the power of the media and how serious the consequences can be if reporting is not balanced and informed.”

In summary, people need to discuss medical decisions with health professionals, but it's also vital that health reporting is balanced, measured, and clear.

Medical Journal of Australia, 2015. DOI: 10.5694/mja15.00103 (About DOIs).