I understand that the OP's question pertained solely to EU requirements, but FDA expectations were referenced above. My experience and understanding of FDA's approach to this question is partly different from that of the esteemed prior answerers.
The prior answers are correct in that real time aging is mandatory to verify the results of accelerated aging. The difference is in regard to marketing the device prior to completion of at least some of that real time aging.
I'm at home without access to my annotated files, but see
this device-type-specific guidance as an example. Refer to the last paragraph of Section E.
Note the important caveat that this paragraph applies only to devices with established materials and designs.
Given this caveat, FDA accepts 510(k)s...at least in my experience...that declare device-sterility and device-functionality shelf lives, and include labeling stating the shorter of those two lives,
based only on validated accelerated aging. There is no requirement to have
completed any degree of real time aging prior to marketing. FDA however does expect the 510(k) to include a statement that real time aging is
underway and will be followed by testing at appropriate time-increments (for instance, typically annually for a five-year-expiration-date sterile disposable) to verify the shelf life declaration, with the results of satisfactory completion of that verification testing placed in the device's records for possible later FDA review.
Regarding the requirement for validation of the accelerated aging process used, my understanding is that this validation must occur
before the accelerated aging process that results in determination of the shelf life to be declared in the 510(k). This importantly is why the guidance applies only to established materials and device types.
The real time aging that is conducted to verify the accelerated aging is not this validation.
