To extend the lifetime of an offshore wind turbine, a lifetime reassessment is required to determine the remaining lifetime. In this case, the lifetime is recalculated using the combinations of environmental parameters (wind and wave effects) that actually occurred during the lifetime and which normally differ from the assumed conditions during design. The computational effort of such a lifetime reassessment is significant, as a very large number of aeroelastic simulations has to be carried out. Therefore, according to the state of the art, the number of considered combinations of environmental parameters is reduced similar to the design procedure. In this work, an alternative approach for the lifetime reassessment is investigated in detail. It keeps the full set of combinations of environmental parameters and also considers normal operation as well as idling. The challenge of the high computational effort is resolved by using Kriging meta-models instead of aeroelastic simulations. The meta-model-based approach is compared to two other methods for lifetime reassessment: First, the reference method, i.e., a full lifetime reassessment using aeroelastic simulations where all actually occurred combinations of environmental parameters are considered. And second, the approach according to IEC 61400-3. The results show that it is possible to use meta-models instead of the original simulation model for the lifetime reassessment. The computing time can be significantly reduced compared to the other two methods, while maintaining a high approximation quality in the prediction of the lifetime fatigue loads.