Lymphoproliferative disorders after adult kidney transplant: epidemiology and comparison of registry report with claims-based diagnoses.

BACKGROUND: Posttransplant lymphoproliferative disorder (PTLD) is a major complication of kidney transplant.

STUDY DESIGN: Retrospective cohort study comparing PTLD incidence rates using US Medicare claims and Organ Procurement and Transplantation Network (OPTN) data, examining risk factors for PTLD in OPTN data, and studying recipient and graft survival after PTLD diagnosis.

SETTING & PARTICIPANTS: All adult first-transplant patients who underwent deceased or living donor kidney-only transplants in 2000-2006 (n = 89,485) followed up through 3 years posttransplant.

PREDICTORS: Recipient and donor characteristics, HLA mismatches, viral serologic test results, and initial immunosuppression.

OUTCOMES: OPTN-reported or Medicare claims-based PTLD diagnosis, recipient and graft survival after OPTN-reported PTLD diagnosis.

MEASUREMENTS: Adjusted HRs for PTLD diagnosis estimated using a Cox proportional hazards model; probability of survival free of all-cause graft failure estimated using the Kaplan-Meier method.

RESULTS: The incidence rate of PTLD during the first posttransplant year was 2-fold higher in Medicare claims (0.46/100 patient-years; 95% CI, 0.39-0.53) than in OPTN data (0.22/100 patient-years; 95% CI, 0.17-0.27). Factors associated with increased rates of PTLD included older age, white race (vs African American), induction with T-cell-depleting antibodies, Epstein-Barr virus seronegativity at the time of transplant, and cytomegalovirus seronegativity at the time of transplant. The adjusted risk of death with graft function was 17.5 (95% CI, 14.3-21.4) times higher after a report of PTLD, and the risk of death-censored graft failure was 5.5 (95% CI, 3.9-7.7) times higher.

LIMITATIONS: Shortcomings inherent in large databases, including inconsistencies in patient follow-up, reporting, and coding practices by transplant centers; insufficient registry data to analyze acute rejection episodes and antirejection treatment; no available data for potential effects of different types of PTLD treatment on patient outcomes.

CONCLUSIONS: Despite the limitations of data collected by registries, PTLD clearly is an important complication; both mortality and death-censored graft failure increase after PTLD.