‘Diagnosis creep’ threatens validity of guidelines

Are we expanding guidelines too far and diagnosing patients with conditions they don't have?

---

 

Australians are increasingly facing ‘diagnosis creep’, where disease definitions are widened and people are unnecessarily turned into patients, experts say

Dr Ray Moynihan (PhD), senior research fellow at Bond University, said expanded disease definitions were often decided upon by panels muddied by conflicts of interest, and had the potential to be harmful.

Writing in Australian Prescriber, Dr Moynihan quoted the former president of the UK’s Royal College of GPs, Dr Iona Heath. “Whenever I see the sort of guidelines that are, right now, driving overdiagnosis and overtreatment, I think of this: our responsibility not to follow the rules,” Dr Heath has said.

The psychiatry handbook, the DSM-5, had been widely criticised for expanding the scope of a number of disorders, Dr Moynihan said, but the same phenomena had played out multiple times with the development or expansion of prediabetes, hypercholesterolemia, gestational diabetes, hypertension and osteoporosis.

And his own research had revealed that people on panels deciding guidelines often had extensive financial links to industry, Dr Moynihan said.

A 2013 analysis by he and his colleagues looked at conflicts of interest on panels that had affected the way disease definitions were constructed, finding almost all decided to widen the definition.

“What was particularly obscene was the fact that the people who sat on the hypertension panel were directly tied to companies that sold hypertension drugs. It’s no surprise, but it’s such an egregious conflict of interest,” Dr Moynihan said.

Twelve of 14 panels were chaired by someone with industry ties, and the average number of companies a member with disclosures was tied to was seven.

“However hard it is, this is why doctors need to be suspicious about the disease definitions and the diagnostic thresholds that are given to them via guidelines,” Dr Moynihan warned.

But contradicting guidelines could raise concerns about possible legal ramifications, and it was time for medical bodies such as the RACGP to give this serious attention, he said.

One fear among doctors is that they might miss something, so there’s a tendency to do more than is necessary, and diagnose and treat more than necessary to mitigate that fear of litigation, he said.

“But if that fear of litigation is genuinely standing in the way of us addressing too much medicine, then we have to confront it.”

Professor Paul Glasziou, director of Bond University’s Centre for Research in Evidence-Based Practice, agreed it was time for the RACGP to seriously vet guidelines that changed disease definitions.

The numerous and changing guidelines impact on GPs, who then have to interpret which definition to use, making it very difficult for the average practitioner to grapple with what it all means in context, he said.

“We either need a system where there is a lot more generalist input to guidelines and clearer rules about the development of guidelines … or else we need to train up all GPs to be more critical. Probably a combination of both is ideal,” Professor Glasziou said. 

He commended the RACGP for holding the line against introducing new broader definition for gestational diabetes to Australia in its 2014 guidelines.