• adherence;
  • pharmacoeconomics;
  • medication;
  • renal function

Study Objective

To determine the influence of pill burden and drug cost on outcomes after renal transplantation.


Retrospective medical record review.


Kidney and pancreas transplantation center.


Sixty-eight adults who underwent kidney or kidney-pancreas transplantation during 2007.

Measurements and Main Results

The median pretransplantation pill burden was 15 pills/day, which increased to 25 pills/day at 1 month after transplantation and returned to 16 pills/day by 1 year after transplantation. Pretransplantation pill burden was lower than the burden at 1, 3, 6, 12, and 24 months after transplantation (p<0.05). The mean pretransplantation drug cost of $1918/month was lower than the cost at 1 month after transplantation ($2564/mo, p=0.04) but was similar thereafter. Higher pretransplantation pill burden was associated with increased serum creatinine concentration at 6 months after transplantation (r=0.288, p=0.017). Higher pill burdens at 1 month (r=0.364, p=0.002), 3 months (r=0.332, p=0.006), and 6 months (r=0.374, p=0.002) were associated with increased 3-month serum creatinine concentration. Higher drug costs were associated with increased serum creatinine concentrations throughout the study.


Higher pretransplantation pill burden and higher drug cost may be associated with poor renal function after transplantation. Further study addressing factors associated with nonadherence is needed.