At higher altitudes due to the greater pressure differential the airflow would be much higher through the same sized initial breach made by the bomb (reaching 'explosive' pressure expansion rates), possibly causing more secondary damage that could then be further propagated by the greater slipstream loads on exposed surfaces.
However I'm no expert, it could well be that the additional secondary loads would make little difference and we would see no more than current damage, most of which I'm sure was caused by the initial blast. There was the United 747 which had a cargo door failure that ripped a good part of the cabin wall open at cruise altitude, there was no visible further damage caused by secondary aerodynamic forces, and the aircraft landed fine just like this one.