Kernrechtsfrage
Whether the lower courts violated the duty to investigate by relying on outdated or insufficient medical evidence in the revision procedure.
Extrahierter Entscheid
Yes. Because both treating doctors indicated a deterioration and the available record did not reliably establish the medical situation up to the decisive date, further clarification was required.
Extrahierte Begründung
Under the inquisitorial principle, the administration and court must fully clarify relevant facts. If the treating physicians' reports were considered inconclusive, an additional medical assessment had to be obtained; otherwise, assuming unchanged health was not sufficiently established.