Clinical studies on children have become a regular feature in medical journals, but a new review of such trials has found that about half of them, especially the industry-funded ones, appear to be biased.
The review by a team from the Johns Hopkins Hospital, Maryland, found that 40 to 60 per cent of the studies either failed to take steps to minimise risk for bias or to at least properly describe those measures.
The researchers, who examined 150 randomised controlled paediatric trials - all published in well-regarded medical journals - said their findings should be taken as an eye-opener and advised medicos to be critical readers of studies, even in highly respected journals.
The report, published in journal Pediatrics, showed that experimental trials sponsored by pharmaceutical or medical-device makers, along with studies that are not registered in a public-access database, had higher risk for bias.
So were trials that evaluate the effects of behavioural therapies rather than medication, the report stated.
"There are thousands of paediatric trials going on in the world right now and given the risk that comes from distorted findings, we must ensure vigilance in how these studies are designed, conducted and judged," said lead researcher Michael Crocetti, a pediatrician at Johns Hopkins Children's Centre.
"Our review is intended as a step in that direction."
The researchers said results of clinical trials, when peer-reviewed and published in reputable medical journals, can influence the practice of medicine and patient care.
But, a poorly designed or executed trial can lead researchers to erroneous conclusions about the effectiveness of a drug or a procedure, they said.
Citing the degree of bias risk in the studies they reviewed, the researchers cautioned pediatricians to be critical readers of studies, even in highly respected journals.
The investigators advised that when reading a report on a trial, pediatricians should not merely look at the bottom line but ask two essential questions: How did the researchers reach the conclusion? and Was their analysis unbiased?
Doctors should apply "smell tests", common sense and skeptical judgement about whether the conclusions fit the data, especially when a study boasts dramatic effects or drastic improvement, they said.