Heel pad thickness in acromegaly

A precisely defined method of measuring thickness of heel pad is described. Errors in radiographic technique may significantly alter the measurement. Heel pad thickness in 52 control subjects and 79 patients with untreated acromegaly is analysed. In these samples of control and acromegalic poplations, minimum misclassification is achieved as follows: allocate to acromegalic group if heel pad thickness exceeds 23 mm in males and 21·5 mm in females. Heel pad thickness is related to body weight. The effect of age is less important when weight is taken into account. Some improvement in separation of controls and acromegalics is obtained when a statistical technique of discriminant analysis is applied to the measurements of heel pad and body weight. Thickness of heel pad in acromegaly is probably related to the severity of the disease. It is greater in patients whose disease is of long duration (more than 15 years) than in patients who have had the disease for less than five years, and is correlated with serum level of growth hormone. Heel pad thickness is reduced in some patients whose serum level of growth hormone is diminished by more than 50 per cent as a result of 90Y pituitary implantation.