Medication errors and adverse drug events in kidney transplant recipients: incidence, risk factors, and clinical outcomes.

STUDY
OBJECTIVE: To determine the incidence, risk factors, and clinical outcomes associated with clinically significant medication errors or adverse drug events in kidney transplant recipients.
DESIGN: Retrospective observational study.
SETTING: Transplant center at an academic medical center. PATIENTS: A total of 476 adults who received kidney transplants between June 2006 and July 2009.
MEASUREMENTS AND MAIN RESULTS: Severe or significant medication errors and adverse drug events (medication-related problems [MRPs]) were identified by medical record review. Only patient-induced medication errors (e.g., took wrong dose or frequency of drug, took drug not prescribed) were captured. Clinical outcomes included patient and graft survival, infections (including cytomegalovirus), readmissions, and acute rejection episodes. Thirty-seven (8%) of the 476 patients developed a clinically significant MRP. Univariate and confirmatory multivariate analyses revealed that female sex, African-American race, pretransplantation diabetes mellitus, delayed graft function, and retransplant recipients were independent risk factors for developing an MRP. Patients with MRPs had significantly higher rates of acute rejection (11% vs 30%, p=0.004), cytomegalovirus infection (15% vs 30%, p=0.033), and 30-day readmissions (5% vs 16%, p=0.018). Graft survival was also significantly lower in patients who had MRPs (p<0.001).
CONCLUSION: Patient-induced medication errors and associated adverse drug events were common in kidney transplant recipients. General and transplant-specific risk factors were associated with the development of these MRPs, and MRPs were associated with increased risk of rejection and graft loss.