Adaptive coded modulation is a spectrally efficient wireless transmission scheme when the transmitter has perfect channel knowledge. We analyze how the performance of adaptive coded modulation schemes deteriorate when only partial channel state information is available due to imperfect channel prediction. The results hold for flat Rayleigh fading, constant transmit power, perfect coherent detection in the receiver, an arbitrary number of independent receive antenna elements, maximum ratio combining,and any linear fading predictor based on periodically transmitted pilot symbols.