Bmj Research Paper Year
Discrepancies in bone marrow stem cell trials
Do stem cells taken from the bone marrow and injected into patients with heart disease improve heart function? Lots of people believe so, and meta-analyses by the Cochrane Collaboration show a significant positive effect.
But individual trials produce conflicting results, for no very obvious reason. Darrel Francis, professor of cardiology at Imperial College in London, says: “Some things in the early trials didn’t add up and when we went to the journals that published them, we were fobbed off. So we decided to look at discrepancies in all the published trials.” Discrepancies were defined as two or more reported facts that cannot both be true because they are logically or mathematically impossible.
The team’s paper, published in The BMJ, concluded that the more discrepancies a paper contained, the more positive its results. “This field of therapy appears to be most effective in the hands of researchers whose reports contain factual impossibilities,” say Francis and colleague Graham Cole. “Indeed, when the factual impossibilities disappeared, so did any effect of the therapy.”
They expected a sharp reaction from researchers with many discrepancies. “We tried to soften the blow by not naming the hundreds of report authors directly,” Francis says. “But it was authors with few discrepancies, and small or zero effect sizes, who criticised the study most vocally.” This includes the Cardiovascular Cell Therapy Research Network, funded by the US National Institutes of Health with $30 million, whose data coordinator, Lem Moyé of the University of Texas, told people to disregard the …
Oxygen saturation targets in infants with bronchiolitis
Bronchiolitis is a common infection in infants, often caused by respiratory syncytial virus. A minority of children require admission to hospital, where oxygen levels are monitored and supplemental oxygen provided if oxygen saturation falls below a threshold. The question is: where should that threshold lie?
Steve Cunningham of the department of child life and health at Edinburgh University and colleagues designed a double blind trial in which infants were randomised to targets of 90% or 94% oxygen saturation.1 “That sounds a small difference but it captures a lot of patients,” he says. “We wanted to know what it means in terms of outcomes if you go for 90% rather than 94%. The other question is what does it mean for services?”
The answer is that there is no clinical difference. Time to resolution of cough—the primary outcome—was the same in both groups. “The other outcomes were better in the lower oxygen group,” he says. “The kids started feeding sooner and the parents’ perception, which is pretty important, was that the kids got better sooner.” This suggests that higher oxygen levels may be detrimental, possibly because they speed virus replication.
The findings have service implications because they mean that fewer patients will require supplemental oxygen and in those who do the time it is needed is reduced from 27.6 hours to 5.7 hours. For paediatric hospitals bronchiolitis is a huge issue every winter. “There’s a six-week period, between mid-November and the end of December, when the whole thing is gridlocked,” Cunningham says. A lower oxygen threshold can reduce that pressure and in future may enable oxygen at home rather than in hospital—as is already done in some places …