If the PA billed an E/M and not a procedure, then there's no global period, so there's nothing to be considered "incident to". Even if he did bill an actual procedure, the global period doesn't apply to the MD, because you billed the PA's individual NPI as the rendering provider, and the MD will have a different individual NPI.
However, the MD's visit will be considered Established and not new, because he is the PA's supervising physician, so they will be considered part of the same practice and same specialty. Hope that helps!