Predicting time on the waiting list for HLA matched corneal grafts

Recent studies report the beneficial effect of HLA matching for the long-term prognosis of penetrating keratoplasty (KP). This improvement in prognosis, however, has to be weighed against the additional waiting time while a HLA compatible graft is found. Precise estimation of this additional waiting period is a prerequisite for informed consent on the waiting policy. A mathematical model based on survival analysis and HLA haplotype frequencies was used to estimate time on the waiting list for each of 1400 HLA typed patients registered at the Lions Cornea Bank North Rhine Westfalia (NRW). Additionally, the waiting period for each patient was retrospectively determined. Both values were tested for correlation. This analysis was performed for acceptance of up to two mismatches on HLA-A, -B and -DR. The median predicted waiting period was compatible with the median waiting period in retrospective simulation. Correlation of both entities was statistically significant also. Predicted time on the waiting list as derived from the patient's HLA genotype and a comprehensive database of HLA haplotype frequencies is thus a valuable tool for management of HLA-matching in KP.