Diabetes mellitus occurs in approximately twenty per cent of patients and is secondary to insulin resistance as a consequence of raised GH levels. Hypercalcaemia occurs in five to ten per cent of patients usually resulting from parathyroid adenomas or hyperplasia (MEN type 1). There is also a five per cent increased incidence of urinary calculi resulting from hypercalciuria, even in the absence of hypercalcaemia. Hypercalciuria occurs in eighty per cent of acromegalic patients because GH is facultative in the synthesis of vitamin D and levels of 1,25-dihydroxycholecalciferol are raised.
