Paying for Participation in Placebo-Controlled Clinical Trials?

by Mario Rizzo  

A couple of weeks ago I received a letter from the Harvard Medical School inviting me, among many others, to participate in a placebo-controlled trial of the efficacy of omega-3 (fish oil) supplements and high dose Vitamin D in preventing disease. The trial would last for five years.  

I thought about it for a few minutes. But it seemed very risky. Why?  

Based on my reading of the evidence (as presented in the popular press but also in a few journal articles that I have read) I am convinced that these supplements are highly likely to be efficacious. In fact, I current supplement with 1200 IUs of Vitamin D and 3 grams of omega-3 per day.  

If I were to enroll in the trial I would have to give that up and take the chance that I would be taking a placebo. Why should I do that?  

The only reason I can think of is to be socially beneficent. I could help establish more definitively whether, in fact, this supplement regimen is beneficial. On the other hand, I am just one person – and one person or less won’t make much of a difference.  

But the expected cost to me personally is significant. So “beneficence” would really be an altruism of sorts. This is a significant difference.  

More importantly, those people most likely to participate in the study are those who are less informed, I should think, about health matters. They are probably less likely to follow healthful practices in the first place. I do not know how this will affect the results. It could be that scientists will find a greater or lesser effect in this group.  

The point is that this problem affects participation in those cases, especially, where people are generally healthy now and simply want to stay that way. If, on the other hand, people have a hard-to-treat disease and the trial gives them a possible access to a drug that they cannot obtain in any other way, participation would be much more likely.  

Is it time for people in clinical trials, such as the one to which I was invited, to be paid or given some other benefit? I realize that this may compromise certain criteria of randomness. But no system is perfect.

10 thoughts on “Paying for Participation in Placebo-Controlled Clinical Trials?

  1. I think you haven’t accounted for the fact that the supplements you’d get from the study are free to you. So the choice for a person like you is actually between paying for a 100% certainty of getting the supplements you want, or having some uncertain liklihood of getting those supplements, but getting them for free. I’m not saying that it would change your mind since I presume that the cost of the supplements doesn’t strain your budget and you seem to believe that the benefit they provide is quite high. However, for someone more skeptical of their benefit and/or on a tighter budget, I can certainly see why they would participate for free.

  2. Hi Mario, I got the same invitation and declined for similar reasons, plus one extra: they would force me to switch from salmon, which I currently eat to get omega-3s, to supplements, which generally become rancid and toxic before they are eaten.

    Fish is a great source of omega-3s, but supplements are not. See:

  3. Mario,

    The conventional wisdom is that people who participate in such tests have greater knowledge about health and are more responsible (i.e., likely to follow the regime). This is one reason for bias in such trials. There was a long article in th NYT magazine about such tests a couple of years ago.

  4. I think your post is a clinical trial of sorts. You’re trying to identify those opinions or facts about your life which when revealed draw Brad DeLong out of the wood work to call you an insane sociopath!

  5. The existence of people like you, who already do the activity in question before entering a medical trial, poses an interesting question in itself. Suppose that high vitamin D and omega-3’s do support health. After you join the trial, say you’re assigned to the treatment group (not the control). Your health remains constant, because your behavior has not changed. That would seem to dampen the perceived impact of the treatment. Or maybe you’re assigned to the control group. Then your health declines because you’re no longer dosing yourself. That would seem to amplify the perceived impact of the treatment. If you’re equally likely to be assigned to either group, and the number of subjects is high enough, then maybe these two effects cancel out. But it might raise other problems in data analysis.

  6. I would avoid fish oil supplements, and eat fish, walnuts, etc. instead. (I’d also avoid vitamin pills/capsules and eat a well balanced diet. The one exception: vitamin C powder, if you consume bottled water. Put one pinch in the bottle; the nasty chemical–which I can’t spell or pronounce– neutralizing effect lasts for an hour.)

  7. Dr. Rizzo,

    You asked, “Is it time for people in clinical trials, such as the one to which I was invited, to be paid or given some other benefit?”

    It is more common than not for drug companies to pay people for their participation in clinical trials. The most common reason for the payments are to compensate for the time required for office visits. Typical rates are $70 to $150 per 1 to 4 hour office visit. Many sleep studies pay $300 to $1,000 for an overnight stays.

    Second, you are referring to Vitamin D3, not Vitamin D (which also can be D1, D2, D4, D5). Their functions are different. The Harvard/NIH VITAL study isn’t always clear on it, but they are studying the dose of 2,000 IU’s of D3.

    Third, you seem to be making the assumption that the case for supplementation with Vitamin D3 is proven and needs no further research. I guess some scientists, such as Dr. JoAnn E. Manson, think otherwise–the jury is not in. We have gone through the same thing regarding the risks and benefits of many vitamins. Dr. Manson believes it is not certain whether healthy people have higher D3 levels or higher D3 levels make people healthy (i.e. correlation does not imply causation).

    Fourth, you are assuming “most” participants would be uninformed. Many people in the general public might be uninformed, but assuming most participants would be uninformed sound like elitism. Many members of the public are uninformed because they are passive (they also might know nothing of dark energy, dark matter, and dark flow). Volunteering for a study is active participation–not passive. It is likely nearly 100% of participants will be well aware of the potential benefits of Vitamin D3 & Omega-3 supplementation (at very least from the process discovering and joining the study).

    The study participants just might be skeptical of supplementation. They might prefer eating more fish, watching their diet, and exercising, and even getting some sun (i.e. vitamin deficiency bad AND over-supplementation bad). The reasons why people might join the study are numerous, but being uninformed is doubtful. Who else would join the study? The participants are not monetarily compensated. Free markets require incentives. If people are doing it for the good of society, I would think they would want to know about the actual benefits to society and the risks to themselves. If they are doing it for the benefit of free D3 and omega3, then they likely believe the risks of not supplementing D3 & Omega3 are lower than what you believe. They are not doing it solely for the obligation of popping a placebo every morning for five years.

    I believe people that are most likely to participate in the study are actually more informed on health matters and more likely to follow healthy practices (like eating right and excercising). It might be better to compensate participants in this study to entice people who are less informed and less concerned about health matters to participate.

  8. Good point, however most trials I have dealt with do offer some type ofd compensation ranging from 50 to 120 dollars per study visit. Also, the possibility of placebo does exist and in a double blind study you’d have no way of knowing whether you were on placebo or not. However, 5 years is a long time for free supplements if you did get active product. It may be worth it if you knew the exact ratio of probability of receiving active vs placebo. Also, were you not concerned about extreme high dose of vitamin d causing long term side effects? Maybe they’re testing that as well. Bottom line, studies do pay for participation, burt its labeled as time and travel costs at a significant markup.

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