Deterioration of glucose tolerance in hypertensive patients on prolonged diuretic treatment.

Glucose tolerance was investigated in 51 hypertensive patients before and after 1 and 6 years of treatment with oral diuretics. Glucose tolerance was unchanged after 1 year but had deteriorated significantly after 6 years' therapy. In a comparable group of 16 patients tested at similar intervals in which diuretic therapy had been given only for 3 of the 6 years there was no change in glucose tolerance, suggesting that prolonged oral treatment with thiazide diuretics is diabetogenic.