IGF1 and acromegaly: When glucose-suppressed plasma GH levels during OGTT and normal age-corrected IGF-I values were used to define the biochemical remission of acromegaly according to recent criteria of endocrinologic cure [52], the 5-year hormonal normalization observed in 9 studies reporting 528 patients was 43% (range 15–60 months) [38, 42, 44–47].