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Peter Gill's blog

Comparative effectiveness research or lack thereof

Peter Gill
Last edited 15th January 2012

An earlier TrustTheEvidence.net blog post on the geometry of evidence described the importance of network meta-analyses. These indirect methods of analysis compare the results from two or more studies that have one treatment in common when comparative effectiveness (CE) research is lacking.

What is comparative effectiveness research? To quote the US Federal Coordinating Council for Comparative Effectiveness Research Report to President Obama in 2009, it is defined as the:

“generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat and monitor health conditions in ‘real world’ settings”

Additional studies that compare one drug to placebo are not incredibly useful when we already know they work. The real challenge of evidence-based practice is determining which treatment to use when all ten available drugs are better than placebo. How do clinicians decide which one to prescribe? All too often decisions are built on studies lacking active comparators. This is not high quality care for patients.

A recent study published in PLoS ONE evaluated trials registered in ClinicalTrials.gov that focused on the top 25 topics identified as priority areas by the US Institute of Medicine (e.g. treatment of atrial fibrillation). The authors looked at studies conducted in the US between 2007 and 2010 and determined the prevalence of CE research.

Despite the importance of this research methodology, only 22% of studies were CE studies and their characteristics varied substantially based on the funding source. Primarily industry-funded studies had the shortest duration of follow-up and were more likely to report positive findings compared to studies with any government funding.

As usual, children get left out. Industry-funded studies were less likely to enroll children when compared to government or nonprofit funded trials. The lack of controlled trials in children is already a problem and there may be a perceptions among drug manufacturers that testing drugs in children brings the risk of increased liability.

The authors hypothesise that the increase in CE research will lead to an increase in the number of studies that fail to support new interventions. Not good for big pharma, but why?

First, trials with inactive comparators (i.e. placebo) are more likely to achieve favourable findings. On the contrary, CE studies tend to produce conservative results regarding the superiority of a therapy compared to other active treatments.

Second, industry-funded the majority of drug and device CE studies meaning that most were designed and conducted by the company marketing the product. There is substantial evidence that these studies are more likely to report positive findings supporting the use of a product. The PLoS ONE study provides further evidence that even in CE research industry-funded studies were more likely to report an outcome favouring the use of the intervention.

But it’s not all doom and gloom. The US has allocated $1.1 billion to CE research. This added investment of noncommercial funding will be critical to provide unbiased answers and evaluate under-studied populations (e.g. children). It’s about time we provide with stronger evidence.

The recent post on whether Christmas is bad for you inspired further questions on the evidence behind holiday season myths. There is a common misconception that poinsettias (Euphorbia pulcherrima for the botanists) are poisonous. Grandparents tell stories to new parents that they must be vigilant to ensure that children don’t ingest the plant’s leaves.

But what is the evidence?

A study published in 1996 in the American Journal of Emergency Medicine sought to provide an answer. The authors evaluated 849,575 plant exposures reported to the American Association of Poison Control Centers. Poinsettia exposures accounted for 22,793 cases, or nearly 3%, of which nearly all occurred in December and January. Not surprisingly, 94% of poinsettia exposures were in children.

But were they poisonous? No. None were fatal. In fact, only 4% of patients required treatment in a health care facility and fewer than 7% developed toxicity. Most reactions were mild - children that ingested leaves may experience diarrhea and vomiting or have an allergic reaction to the skin.

Poinsettias are not toxic. They don’t stalk family homes waiting for the opportune time to poison children with their attractive red leaves. Children that accidentally ingest poinsettia leaves rarely require treatment. In fact, the real concern is that they may be a choking hazard.

Well what are the real hazards around Christmas time? The Children's Hospital of Philadelphia website highlights the harms that children need to worry about. An unsuspecting culprit took the top spot: alcohol. Alcohol is a serious hazard in children that can lead to major health problems if ingested by children, even in small quantities. Be wary of leaving empty glasses around the house that could break and be ingested by children.

Similar to alcohol if you are in a cold enough climate, windshield washer fluid and antifreeze are serious hazards. The sweet tasting liquid that looks like Kool-Aid can lead to blindness, seizures, heart-rhythm changes and even death if ingested.

Other quintessential botanical Christmas symbols that are poisonous: holly. A handful of berries from the Illex opaca shrub can produce nausea, vomiting, diarrhea and drowsiness in children. The toxicity of kiss causing mistletoe is not supported by the evidence with most cases having a similar outcome as with poinsettia exposure. But with all substances, beware of large amounts.

Be on the look out for disc batteries (coin shaped circular ones) that can be a choking hazard if swallowed. If they become stuck in the esophagus or stomach, they can begin to leak their caustic contents and cause severe burns.

Irrespective of the hazard, most children swallow these objects when they are left unattended. When enjoying the holiday season this year, keep an eye on the curious children putting objects in their mouth and dispel the old urban myths that lack evidence. Happy Holidays.

Emergency contraception: emotion, evidence and bubble gum

Peter Gill
Last edited 18th December 2011

Earlier this year, the FDA recommended that emergency contraception, or Plan B, should be available without prescription to girls under 17 as it is currently available by prescription only to this age group. In an unprecedented move, the US Health and Human Services secretary Kathleen Sebelius vetoed the FDA's recommendation to make Plan B available without prescription to all women of childbearing age in the US. Mr. Obama said the secretary felt a 10- or 11-year-old should not be able to buy emergency contraception “alongside bubble gum or batteries."

What is Plan B or emergency contraception? Plan B is a pill that consists of the hormone progestin that works by preventing an egg from being fertilised. It must be used within 120 hours after unprotected sex, is safe and effective with few side effects and none dangerous.

Unlike some misconceptions, the availability of emergency contraception dose not change rates of sexual activity or increase the frequency of unprotected sex among adolescents.

Unintended pregnancies are an emotional and controversial issue, invoking deep-rooted religious, political and ideological beliefs. The US has one of the highest rates of unintended pregnancies with nearly half of all pregnancies unintended. In particular, adolescent birth rates in the US are much higher than rates in other developed countries.

Side stepping the issue of induced abortion, what is the effect of unintended pregnancy on women? A recent Lancet editorial discussed the results of a comprehensive review into the mental health outcomes of women after having an induced abortion. The key study finding was that having an unwanted pregnancy leads to an increased risk of mental health problems, not having an induced abortion.

The US should be leading the battle to reduce unintended pregnancies. Indeed the American Academy of Pediatrics (AAP) “encourages abstinence plus comprehensive sexuality education as the best way to help prevent unintended pregnancy and sexually transmitted diseases.” Further, they support the availability of emergency contraception, or Plan B, for adolescents.

Given that only 20-25% of health care providers discuss emergency contraception with adolescents, the restriction of Plan B to prescription only to adolescents under 17 seems a major barrier to access.

What is the likelihood that a 15-year-old who had unprotected sex is going to get a prescription for Plan B? She will be able to purchase acetominophen (i.e. Tylenol or Paracetamol) without a prescription, a medication that can potentially cause fatal liver damage and lead to liver failure if used inappropriately, yet she cannot purchase Plan B to prevent an unintended pregnancy.

Rather than rely on evidence, emotion wins. But the real loser are adolescents under 17 who may face life-long mental health problems. When emotion wins, we all lose.

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