Poisoning the Well - A Wash-up on the Cochrane Debacle.
The Cochrane Collaboration is an independent, international group which performs systematic reviews of medical trials to eliminate bias and identify poor design. They are very well regarded and, at least until now, have provided an impartial lens on the efficacy of medicines, reducing the distorting influence of researcher bias, and spin from big-pharma and the alternative health sector.
Recently however, to immediate outrage, the Cochrane’s Hepato-Biliary Group dropped a massively contrary, some would say bizarre review of the direct acting antivirals (DAAs) which are currently curing thousands of people of hep C in Australia.
After assessing 138 randomised clinical trials of 51 different DAAs (a large percentage of which did not reach market) they declared that there was no strong evidence that the treatments led to ‘improved survival and fewer complications’. This is another way of saying that there is no confirmed effect on morbidity and mortality. Another way of saying that the drugs don’t work.
This, of course, is nonsense. Very unhelpful nonsense.
Because Cochrane is so respected and influential, there was some shock at the announcement. This was followed by a no-holds-barred global response from practically everyone involved in the treatment of Hep C.
In a reply from a group of Australian specialists, Dr David Iser described the report as ‘factually incorrect’. He pointed to the short term nature of the studies reviewed and the futility of attempting to derive long term outcomes from something not designed to assess such outcomes. ‘Patients should not be swayed by this flawed report and should not defer seeking treatment based on this study,’ he said.
The Cochrane review does highlight the short follow-up periods of most of the studies analysed, but pushes ahead with its scepticism regardless. From my humble position, as a lay person in the matter of statistics, it seems obvious that their work was premature. In five years, perhaps, such an effort may prove useful, once there is actual longitudinal data from which to work. More than once have I heard people express curiosity on the long term effects of DAAs, but there will be a time for that investigation, and that time is not now.
The simple truth, to quote Iser again, is that ‘there is abundant evidence that SVR following treatment of hep C improves survival, and reduces deaths from cirrhosis and liver cancer’. The real world truth, plainly apparent to anyone working in the field, is that the treatment is tremendously effective, and I wonder if the people at the Cochrane Hepato-Biliary Group may somehow have lost themselves in a whirlpool of statistics and forgotten to peek out the window of their ivory tower.
Their review even contains an element which borders on absurdity. In the past, researchers from Imperial College in London performed a systematic review of 31 studies assessing the survival rates of people on the older peginterferon/ribavirin regimen. They concluded that, if treatment was successful (as it was a certain percentage of the time) they could expect to have their risk of death reduced by 50-80% over five years.
One of the authors of this review responded to the Cochrane Collaboration by inquiring if they thought ‘that being cured of hepatitis C by the new drugs is somehow different ... to being cured by the old interferon-based treatments... For most experts, curing Hepatitis C should have the same clinical consequences, no matter what treatment is used....”
Another strange inclusion to the review reads thus: it is questionable if an eradication of hepatitis C virus in the blood leads to no hepatitis C in the body. I wonder if this may harken back to the time when owing, I think, to some anomalous blood test results, it was theorised that the virus may find hiding places in the thyroid gland or in muscle mass. It seems irrelevant today. There may still be the occasional false positive caused by - it has been ventured - dead virus particles in the bloodstream, but to date, I know of no cases of the virus suddenly reappearing down the track from some hidden reservoir in the body.
The review also pointedly refers to the high price of the drugs, seeming to imply that their value may have led to undue pressure from pharma companies on the operation of the studies - which Cochrane describes as low quality and at ‘high risk of bias’. Certainly, these are concerns, and no one is saying that expensive pharmaceuticals have never reached the market without proper investigation, but in the case of DAAs they have chosen the wrong target. Whatever the processes used to assess the drugs, the horse has bolted. All the evidence we need are in the their spectacular results.
At the time of writing most of the furore has died down, but I do worry that this Cochrane report may turn out to be a time bomb. Because of the organisation’s respectability, it is often used by governments to decide whether or not to fund treatments. This creates a risk of swaying the opinion of cautious decision-makers, leery of forking out large sums to treat hep C with DAAs. It is not unimaginable that a life-saving decision could turn on the contents of this review and as such it is not merely a deeply flawed document, but a tremendously irresponsible one as well.
The Golden Phaeton