Sue Ieraci: Diagnosis creep

CONSIDER this paradox: at a time when we have the best access to health care and greatest longevity ever, we seem, as a population, to be more dissatisfied with our health care than ever.

As a general community, we complain about waiting times and waiting lists, we see vested interests everywhere and we perceive our health care system to be in crisis.

As a professional community, we see widespread dissatisfaction, strained resources and strained relationships.

Yet, by any objective measure, preventive and acute medicine are more successful than ever. Vaccination has transformed childhood illness, blood pressure treatment and anticoagulation have minimised stroke, and even asthma in children is on the decline.

Why, then, are we so dissatisfied?

Apart from rising expectations and risk aversion, there is another element at play here that I call “diagnosis creep”.

Where I work, one of the most common presentations is chest pain. Patients presenting with chest pain which could be cardiac are treated as urgent and high-risk until proven otherwise. This makes sound sense in the setting of a possible acute myocardial infarction (AMI), where early revascularisation makes a big difference to outcome.

With better medical care, secondary prevention, smoking reduction and blood pressure control we should be seeing a drop in the number of cases, right?

The fact is we are not doing fewer chest-pain work-ups, we have just shifted our attention to a lower risk group. Of all patients with chest pain admitted for work-up, only a small percentage are found to have AMI.

In these days of high-sensitivity troponin, “troponitis” has become a surrogate for AMI.

Once a non-ST-segment-elevation MI (NSTEMI) meant the electrocardiograph showed ST depression with raised cardiac enzymes. Now patients can be diagnosed with NSTEMI just on the basis of raised enzymes, there may not be coronary occlusion, and the risks and prognosis are not the same as what we used to call AMI. This is diagnosis creep.

Consider also the child with fever. We once worried about Haemophilus influenzae type B (HIB) — now all but vanished with vaccination. We did all those blood cultures for so-called “occult bacteraemia” (wondering if the entity even existed). With pneumococcal vaccination increasing, even this is on the way out. Similarly, few kids today get measles or mumps, or even chickenpox.

So, do we worry less about the febrile child? Well, no. We still do tests, swabs, observation — “it could be a urinary tract infection”.

This issue was recently covered in a study that looked at the publications of recent national and international guideline panels making decisions about definitions or diagnostic criteria for common conditions in the US.

What did they find? Almost all of the groups recommended changes to disease definitions that increased the number of individuals considered to have the disease. Some included a definition of “pre-disease”. None considered the potential harms of widening the definition, of making previously “well” patients ill.

Perspective is needed. If we’re getting sick less and living longer, we are probably, as a society, doing OK.

As they say on the UK Underground, “Keep calm and carry on”.
 

Dr Sue Ieraci is a specialist emergency physician with 30 years’ experience in the public hospital system. Her particular interests include policy development and health system design, and she has held roles in medical regulation and management.