Contribution of individual drugs to gingival overgrowth in adult and juvenile renal transplant patients treated with multiple therapy.

Drug regimens for transplantation often consist of multiple therapeutic agents and may result in drug-induced gingival overgrowth (DIGO). The aim of this study was to investigate the contribution of individual drugs in renal transplant patients. 147 adults (19-84 years) and 60 juveniles (3-18 years) were scored for DIGO and other clinical variables. Duration of treatment, dosage of drugs per kg body weight and serum cyclosporin levels were recorded. 44% of adults and 27% of children had DIGO. All patients were receiving prednisolone. More adults than children were administered cyclosporin, the reverse was true of azathioprine (p<0.01). Explanatory models were evaluated by stepwise ordinal polynomial logistic regression. Statistically significant explanation (p<0.05) of DIGO was afforded by prednisolone, nifedipine and azathioprine concentrations in adults and by cyclosporin, nifedipine and azathioprine concentrations in juveniles. Prednisolone and azathioprine were inversely related to the degree of DIGO. Plaque and irregularity scores, lip coverage and mouthbreathing status showed significant additional explanation in adults, replacing nifedipine and azathioprine in the final model. Irregularity was additionally explanatory in children, but no other clinical variables. A larger proportion of the variance of DIGO was explained by the available variables in children than in adults (pseudo r2=0.50 versus 0.25). The degree of DIGO in renal transplant patients is influenced by the dosage of a number of individual components of multiple drug therapy independently of the presence of local clinical factors.