Diabetes mellitus is an increasingly prevalent condition among corneal donors and recipients, with more than one-third of donor corneas originating from individuals with diabetes. This disease can impact mitochondrial function, corneal endothelial cells, and Descemet’s membrane. It can lead to higher rates of tissue damage during Descemet membrane endothelial keratoplasty (DMEK). Many surgeons and eye banks avoid tissue from diabetic donors. Earlier studies have revealed inconsistent data on the impact of donor diabetes on graft results. Some suggest that elevated endothelial cell loss and decreased graft success, while others found no major effects.
The DEKS was established to determine whether donor diabetes status and severity affect the graft success and endothelial cell loss after low to mild-risk DMEK. The main aim was to evaluate the 1-year graft success rate, with secondary analyses evaluating the tissue preparation, intraoperative and postoperative complications, and the effect of diabetes severity on the results.
The DEKS trial was a randomized clinical trial conducted by the National Institutes of Health at 28 clinical sites and 13 eye banks in the United States. The trial included individuals aged 30 to 91 years old with low to mild risk DMEK, mainly for Fuchs endothelial corneal dystrophy, pseudophakic corneal edema, or failed prior keratoplasty. Donor and recipient diabetes status was determined using medical history and hemoglobin A1c measurement with a postmortem HbA1c test, which is used to reclassify the donors. Donor corneas were assigned in a 2:1 ratio. Postoperative follow-up involved assessments of graft clarity, endothelial cell morphology, and complications. The primary outcome was 1-year graft success, which was defined as the absence of regraft or continuous corneal clouding.
About 1421 eyes from 1097 recipients were included, with 912 eyes receiving tissue from donors without diabetes and 509 with diabetes. Baseline characteristics of recipients and donors were balanced in groups. Tissue preparation failure was high with diabetic donor corneas (6.1% vs 1.6%, P < 0.001) because of increased rigidity and adhesion of the Descemet membrane. Intraoperative and postoperative complication rates involving air reinjection for partial graft detachment were similar in the groups. At 1 year, the cumulative graft success rate was 96.3% for donors without diabetes and 97.1% for donors with diabetes, a difference of 0.7 percentage points; P = 0.63. Donor diabetes severity showed no significant impact on graft outcomes. Primary donor failure and early surgical-related failure were rare and comparable in the groups. Graft rejection occurred in less than 1% of eyes. Recipient age, indication for keratoplasty, and recipient diabetes status did not modify the effect of donor diabetes on graft result.
The DEKS study indicates that DMEK is a very successful and safe surgery for corneal endothelial dysfunction, especially FECD, with high 1-year graft success despite donor or recipient diabetes status or severity. Donor diabetes had no effect on endothelial cell loss or morphometry, which indicates that favorable outcomes are likely to remain over time. These results give strong evidence that donor corneas can be used throughout the whole diabetes severity spectrum, potentially expanding the donor pool despite regulatory limitations and traditionally limited tissue availability. While tissue preparation from diabetes donors is significantly more difficult, clinical results are comparable, allowing surgeons and patients to use diabetic donor tissue for DMEK confidently.
Reference: Price FW, Szczotka-Flynn LB, Price MO, et al. Donor Diabetes and 1-Year Descemet Membrane Endothelial Keratoplasty Success Rate: A Randomized Clinical Trial. JAMA Ophthalmol. doi:10.1001/jamaophthalmol.2025.4253
