There's one small problem for those excusing CASA's appeal to "prudent caution": one of CASA's own published Aviation Medicine case studies.
It's the one describing "Jim's" stroke at age 76, which finally grounds him (just in case this, my first PPRUne post, does not permit URLs, and any of you need to search).
In this case study, CASA describes grounding a pilot who has a stroke, at the age of 76. This means, by CASA's own documentation, CASA continued to renew Jim's Class 1 medical certificate (with conditions) when Jim was aged 75, and diagnosed with Type 2 diabetes, and known to have high cholesterol and high blood pressure.
Here are some "medical" stats:
1. The absolute annual risk of one quite severe medical condition (mild death, with recurring symptoms) for the average 75 year old Australian male is about 4%. Just go to the ABS and take a look at the life tables to confirm. 5% annual chance of death is reached at about age 77 for the average Australian male.
2. Life expectancy for people with Type 2 diabetes is substantially reduced, possibly up to 10 years. If I need to find credible data, I will, but I am sure the forum medical experts will have such data on-hand and should be happy to quote.
3. Thus, the absolute annual risk of death for 75 year old "Jim" with diabetes, plus CASA-documented high cholesterol, plus CASA-documented high blood pressure is "significant" / "non-trivial". You don't need advanced maths/stats to know that it's "significantly higher" than the 4% annual risk for the average 75 year old male. As a guide, IFF the life expectancy for a Type 2 diabetic Australian male is, say 75, then Jim had a 50% total chance of already being dead at the age CASA renewed his Class 1 medical certificate. Despite my limited medical expertise, I am confident that death is regarded as an incapacitating condition with substantial negative consequences, even among lay-people. And that's before we consider what other non-death incapacitations diabetic old "Jim" might also be at a higher risk of suffering (it's debatable whether we should lump in the full risk of Jim's actual factual stroke with the general elevated risk factors already identified for Jim - it's a veritable smorgasbord of possibilities for his age and documented conditions).
I have read the Ambekar and Adamczyk studies, and it is not credible to contend that CASA's approach between Clinton's case and Jim's case is objectively consistent from a statistical safety-driven standpoint. The only way to get close (from a statistical risk viewpoint) is to assume that the consequences of (just a) recurrence of a DAVF after having been "nominally cured" (ie. Clinton's current state) is worse than the consequences of actual death. I don't need to be a specialist in anything, or beat my chest about experience/qualifications to state authoritatively that the incapacitation consequences of DAVF recurrence cannot be worse than the incapacitation consequences of death.
So, for those of you who think CASA's approach in these two cases is "consistent", please explain what stats, studies and numbers you are using to justify your "trumps". For me, it's just about the numbers - and using population-level stats, plus CASA's own published information and cited studies, their approach to pilot incapacitation risk/safety cannot be described as consistent in these two cases.
It's also obvious that if the default approach is: " we're not sure, so we'll ground if in doubt and defend initial decisions no matter what", then pilots have a strong vested interest in never revealing anything voluntarily to their regular GP or "DAME". That's objectively a sub-standard outcome.
And a CASA medical officer who effectively instructs an "independent expert" doesn't seem confident that his own conclusions will be confirmed. This behaviour is indefensible [in a decision review scenario].