Peek-a-Boo: Unmasking blinded studies

I love Halloween … the pumpkins, the corn stalks, the hay rides, the hot apple cider and, of course, the trick-or-treaters.

From walking my two dogs, I have come to know most of the kids in my neighborhood. So, I enjoy matching each child to the character they have chosen to portray. Usually it’s fairly easy. Although, as I get older, I find that I am increasingly out of touch with current film and TV heroes.

However, at least once each Halloween, someone comes with a costume so elaborate or a mask so life-like that their identity is totally obscured. Most eventually tell me who they are but a few leave me wondering for the rest of the night. This year, there was one ghastly, ghostly, grim reaper who had me totally stumped. I still am unsure whether it was a boy or a girl behind that very scary mask with the articulating jaw.

Before our usual Monday morning staff meeting, everyone was talking about the best costumes they had seen. My description of the unknown grim reaper led to a discussion of masks in general. This, somehow, reminded one of our clinical research associates about a discussion she had with one of our investigators about masking, or blinding, during clinical trials.

Dr. Sanders is the owner of a multi-specialty practice in a rural community not far from our office. She has participated in many clinical trials during her career and firmly believes that it makes her a better veterinarian. For that reason, she strongly encourages the other veterinarians in her practice to participate whenever possible.

A few months ago, Dr. Sanders was asked to participate in a study to evaluate a new therapy for a common feline problem. While previous commitments would not permit her to participate, she knew that another veterinarian in her practice could. In fact, Dr. Byrne’s training and experience in feline medicine made him a perfect match for the study. Dr. Byrne eagerly agreed to participate and blocked out time in his calendar for the investigator meeting.

On the day after training, Dr. Byrne screened his first cat, Oscar, a domestic shorthair owned by Mrs. Clark. Dr. Byrne had spent quite a while explaining the study to Mrs. Clark because she had a seemingly endless series of questions. Even after she signed the consent form, he suspected that she would have still more questions as the study progressed. Dr. Byrne’s suspicions were soon confirmed.

“I still don’t understand why you won’t tell me what Oscar is getting;’ Mrs. Clark exclaimed. “I don’t like giving him a pill when I don’t know what’s in it. It makes me wonder whether this study is on the up-and- up.”

“I understand your concern, Mrs. Clark;’ Dr. Byrne said. “But there is a very good reason I can’t tell you. Even I don’t know which pill Oscar will get because this is a double-blinded study.”

“That sounds like the blind leading the blind, and I don’t like it,” grumbled Mrs. Clark.

Dr. Byrne chuckled. “You needn’t worry about that. A double-blind study ensures an objective evaluation of the drug being tested by removing possible bias. In other words, if either you or I knew … or even suspected … which pill Oscar were receiving, we might assess Oscar’s progress, or lack of progress, differently. And that could result in inaccurate study data which, in turn, could result in an ineffective drug getting approved by the US Food and Drug Administration. You wouldn’t want that, would you?”

“Oh no,” Mrs. Clark said as she furrowed her brow and shook her head. “But I still don’t understand why you just don’t give every cat in the study the same medicine. You know, the one being tested. Then, you could ask the owner if it worked or not. Wouldn’t that give you the answer you’re looking for?”

“That study design is called ‘open-label’ and it’s sometimes used when study participants, like you and me, cannot be blinded to the treatment.”

“So, why can’t we do that here? I want to know what the treatment is,” Mrs. Clark said emphatically.

Dr. Byrne thought for a few seconds. “Let me explain it this way. You actually do know what the treatment is. I described the test drug to you when we reviewed the protocol before you signed the consent form. I also explained how the drug works and why Vetco Pharmaceuticals thinks that it will cure the problem Oscar is having.

“The only thing you don’t know is whether Oscar will receive the test drug or a placebo. And, incidentally, I won’t know either because our technician, Tammy, is the only person in the office who will know who gets what. That’s what the protocol requires.”

Just then, Dr. Sanders knocked on the exam room door and walked in. “How’s everything going in here?”

“Mrs. Clark would like to know which treatment Oscar will receive. I explained that the study design requires that both of us be blinded to the treatment to reduce the possibility of bias in either of our assessments of how Oscar is doing,” said Dr. Byrne.

“You’re absolutely correct,” agreed Dr. Sanders. She then turned to Mrs. Clark. “One of the benefits of this study is that, if you feel at any time that Oscar is not improving, we can remove him from the study and treat him with a different medicine. One way or another, we’re going to help Oscar get better. However, by participating in this study, you could be helping lots of other cats get better, too.”

“Ah, that makes me feel much better. You know how I feel about cats. So, when do we start?”