It would be pretty much same fuel flow at 250 kts indicated at 8,000ft as it would have been at 250 kts indicated at 37,000ft. Probably about 4,500lbs/hr. So, the fuel consumption in pounds per hour would be similar at both altitudes.
The big difference would be in the True Airspeed. 275-ish at 8000ft and about 480kts at 37,000ft. So, the fuel consumption in pounds per mile would be much more at the lower altitude.