>> There are many possible reasons for non-diagnosis and the criteria for diagnosis may well vary across communities. <<
There lies the crux of the matter. Just for starters I have three different DX from three rheumy consultants and one doctor disagreeing with the lot - i.e. coming up with a fourth DX! If ALL members of the forum were to consult with the same rheumy, undergo the same tests with the same labs, X-Rays from the same radiographer being read by the same consultant radiologist etc etc then one may have a great study - would be impossible to do!! So, all one could do would be to collect, sift and categorise information provided by members of this forum. Decide 'what' information and make it as broad as possible.
At present we seem to have a couple of such studies underway. When done, then each member could print it out and take along to their rheumy, doctor, et al - present it to em an see where it might lead...

Molly
Keeping on Keeping on