Nonmodifiable characteristics associated with nonadherence to immunosuppressant therapy in renal transplant recipients

Purpose. Relationships between adherence to immunosuppressant therapy and adult renal transplant recipients' age, time posttransplant, race, and sex were evaluated to identify factors that predict nonadherence. Methods. Pharmacy refill data were used to measure adherence. In a primary analysis, stepwise regression was used to assess the relationship between independent variables (age, sex, time posttransplant, and race) and adherence. In a secondary analysis to provide categorical summaries, stepwise regression was used to assess the relationship between independent variables (age quartiles, sex, time posttransplant quartiles, and race) and adherence. Results. In the primary analysis, age and time posttransplant were significant predictors of adherence rate (p < 0.05), with adherence rate decreasing as age and time posttransplant increased. In the secondary analysis, age quartile 4 (>= 60 years) and time posttransplant quartile 1 (<= 4 years) were significant predictors of adherence (p < 0.01), with adherence rates lower among age quartile 4 and higher among posttransplant quartile 1. Conclusion. In patients who had received renal transplants, the rate of adherence to immunosuppressant therapy decreased as patient age and time since transplantation increased.