Currency and clinical trials

How Bretton Woods shaped the first modern RCT

When Austin Bradford Hill and his colleagues set out to study the effects of streptomycin on tuberculosis in 1947, they already had good reasons to believe the drug would be effective. Experiments with guinea pigs had shown promising results, and clinical data from humans suggested streptomycin might improve outcomes for TB patients. Under normal circumstances, this would have made it difficult to split patients into ‘control’ and ‘treatment’ groups to test the effectiveness of the drug. As Bradford Hill argued, ‘it would certainly on ethical grounds have been impossible to withhold the drug from desperately ill patients.’

Unless, of course, there wasn’t enough streptomycin to go around in the first place.

This was precisely the situation that post-war Britain found itself in. Not only was there limited streptomycin in the country, there was little opportunity to get more of it. Acquiring the drug required US dollars, and Britain didn’t have enough of them.

Why were dollars such a problem? It was a consequence of the so-called Bretton Woods system. In 1944, as the Second World War drew to a close, delegates from Allied nations had gathered in Bretton Woods, New Hampshire, to plan the postwar global economy. The agreement pegged national currencies to the US dollar – which was itself tied to gold – making the dollar essential for international trade¹.

This new system didn’t make life easy for Britain. It had emerged from the war in deep debt, with depleted reserves of foreign currency. Under Bretton Woods, the UK would need US dollars to get hold of important goods, including American pharmaceuticals like streptomycin. But strict currency controls were in place, so the British government had to ration what its limited dollar reserves were used for.

This meant that there wasn’t enough streptomycin – or the American currency required to buy more of it – to treat all severely ill TB patients in Britain. When George Orwell contracted the disease later in 1947, he was only able to obtain streptomycin thanks to his US book royalties, which gave him access to dollars.

Faced with an impossible situation, Bradford Hill and his colleagues made a decision that would end up transforming medicine. Since it was impossible to treat everyone, they chose to allocate the available doses at random so they could learn something about the effectiveness. As Bradford Hill later put it:

it would, the Committee believed, have been unethical not to have seized the opportunity to design a strictly controlled trial which could speedily and effectively reveal the value of the treatment

That choice would result in the first modern randomised controlled trial (RCT), a groundbreaking methodology for determining cause-and-effect in medicine. And it all started with a wartime debt, a dollar shortage – and a 1944 meeting at Bretton Woods.

Cover image: Mackenzie Marco via Unsplash

1. Bretton Woods also created the International Monetary Fund (IMF) and the World Bank. Moneyland by Oliver Bullough provides a fascinating overview of Bretton Woods and its aftermath if you’re interested in discovering more.