Sunday Brunch: healthcare, underrepresentation and the flaw of averages

Sunday Brunch: healthcare, underrepresentation and the flaw of averages

Increasing diversity in clinical trials is one of the foundations of health equity

In 1950, the U.S. Air Force took physical measurements from 4,000 pilots across 140 dimensions and took the averages of those measurements to design the 'perfect cockpit'. This robust data-driven approach however did not translate well into flight missions. Once the new cockpits were introduced, previously capable pilots were suffering uncontrolled crashes. So what was going on?

A young analyst, Lt. Gilbert S. Daniels, found that not a single pilot fitted within the middle 30% range across 10 key dimensions. This insight led the Air Force to abandon the average as the design standard. Instead, they adopted a new principle of 'individual fit' by making cockpit components adjustable to accommodate diverse pilot sizes. The notion of an 'average person' was discarded as an inherently flawed concept unable to account for human complexity. The 'flaw of averages.'

And yet that very principle has been central to clinical drug trials for decades.

Look at the efficacy and side-effects for an 'average group' in a trial and apply that to the broader population. In recent years the concept of personalised and precision medicine has come to the fore. That is something for another blog. In today's Sunday Brunch I'll focus on the composition of clinical trials.

Historically, that 'average group' has been far from it.

For example, older Black and Hispanic Americans are twice and 1.5 times as likely, respectively, to have Alzheimer’s than their white counterparts, but the majority of clinical trials have historically featured white patients.

Sex differences are important too. Until the NIH Revitalization Act of 1993, a 1977 FDA guideline banned most women with 'childbearing potential' from clinical trials.

The FDA has noted previously that minorities, the elderly and women have historically been underrepresented in clinical trials. Separately, analysis has shown that a 'standard drug dose' typically leads to higher blood concentrations and longer drug elimination times in women contributing to more frequent adverse drug reactions in women.

That has improved greatly with an FDA drug trials snapshot (2015-2019) showing that male and female participation has become more balanced. However, on a global basis, 76% were described as 'white', with only 7% as 'Black or African American' - the US 2021 census showed more than 12% of the US population were 'non-Hispanic black'.

Back in April 2022, the FDA issued draft guidance 'Diversity Plans to Improve Enrollment of Participants From Underrepresented Racial and Ethnic Populations in Clinical Trials'.

After two years of comments, the FDA is late in issuing final guidance on how and when drug and device companies should submit diveristy action plans for clinical trial research with the document still under review at The White House.

Understanding the particular needs of communities and their involvement in drug trial and discovery is an important part of actually providing access - an important part of health equity.

Before we look a little closer at what is being proposed by the new FDA rules, let's start off with defining what health equity actually is.

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What do we mean by 'Health Equity'?

The World Health Organisation describes health equity as being achieved when "everyone can attain their full potential for health and well-being."

It is quite a broad definition. Let's look at it the other way around. What are the factors that can prevent people achieving their full potential for health and well-being? What are the differences between different people? What are the disparities?

Here is what US Congress had to say about it in the 'Health Equity and Accountability Act of 2022': Health disparities are a function of not only access to health care, but also the social determinants of health that directly and indirectly affect the health, health care, and wellness of individuals and communities, including:

  • the environment
  • the physical structure of communities
  • nutrition and food options
  • educational attainment
  • employment, socioeconomic status
  • race, ethnicity
  • sex, gender identity
  • geography
  • language preference
  • immigrant or citizenship status
  • sexual orientation
  • disability status

Taking all of the above into consideration, we arrive at the following overview:

A 2022 actuarial study by Deloitte concluded that health inequity in the US accounted for roughly US$320 billion in annual healthcare spending potentially ballooning to more than US$1 trillion by 2040 if that inequity was not addressed.

As well as the obvious direct link to UN SDG goal 3, health equity can support and be supported by the other UN SDGs too. The social determinants of health, as mentioned previously, are clear across goals 1-11. Goal 11 itself, "sustainable cities and communities" is particularly pertinent in bringing many social determinants together.

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