Effect of data normalization for age on the correlations between corneometric values and serum molecule levels in plaque-type psoriatic patients.

Corneometry has been considered useful both to evaluate disease severity and to monitor psoriatic patients during treatment. However, a limitation of this technique is that the patient's age influences the corneometric determinations, thus reducing their clinical usefulness. The aim of this study was, therefore, to establish whether age normalization of the corneometric results may provide more reliable data for clinical use. Corneometric levels were determined in 10 plaque-type psoriatic patients, under standard conditions. Eight serum variables, including transforming growth factor-beta 1 and seven soluble membrane molecules, were assayed with commercially available immune-enzyme methods in the same patients, whose age and PASI scores were also recorded. The age normalization procedure improved all the correlation coefficients calculated on the lesional or non-lesional corneometric values versus the PASI scores as well as versus the other serum variables. This approach may render corneometric determinations more useful to evaluate disease status or treatment effect in patient groups with plaque-type psoriasis.